https://cpw.cvlcollections.org/files/original/05333172993d46ffdcb263ed7e24796c.pdf 91cc29e504859e4288379fc798669a6b PDF Text Text C O L O R A D O P A R K S A N D W I L D L I F E 2012 Colorado Angler Survey Fact Sheet Fishing Regulations Review Purpose of the study: To determine the spatial distribution of angling pressure for various species, across Colorado and collect data to help predict demand for sport fish species around the state over the next 30 years. Methods: Between March and August 2012, we mailed a survey to 3,000 individuals who had purchased Colorado fishing licenses in 2011. Half were residents (5% senior, 12% combination, 50% annual and 33% 1-day licenses) and half were non-residents (76% annual and 24% 1- or 5-day licenses). We had a valid sample of 2,577 anglers and received a total of 1,404 responses to the survey (54% adjusted response rate; 56% of residents and 44% of non-residents). Highlights of results: Key findings of this survey were:  Among anglers of all types, the 3 most commonly targeted species were rainbow trout, brown trout and cutthroat trout. All anglers desired an increase in opportunity for these species over other species.  Frequent and moderate anglers were more satisfied with their fishing experience in Colorado than infrequent anglers. Moderate and frequent anglers were very satisfied with the variety of fish and waters they could fish in Colorado. Infrequent anglers were not satisfied with the number and size of fish they caught and the complexity of the fishing regulations in Colorado.  Annual, resident license purchasers fished for an average of 24 days in 2011; annual, non-resident license purchasers fished for an average of 17 days. Senior license purchasers fished for an average of 13 days and combination license purchasers fished for an average of 15 days.  Resident anglers were very satisfied with the variety of fish and water available to them to fish, and their ability to eat the fish they caught. Residents reported the highest level of dissatisfaction with the number and size of fish they caught and the availability of wild fish.  Non-residents were satisfied with the variety of fish and water available to them, and their ability to eat fish they caught. Non-residents were more satisfied with all aspects of fishing than residents.  Colorado anglers spent the highest mean number of days fishing for carp, wiper and striped bass, and bluegill, but these were the least commonly targeted species. The three most commonly targeted species (brown trout, cutthroat trout and rainbow trout) averaged the fewest days fished.  The Colorado population between 51 and 70 years old will decrease over the next 30 years and the population between 71 and 90 years old will increase. This change will not likely affect demand for species or types of access, but may increase participating in fly angling and demand for trout species.  Demographers predict that the white, non-Hispanic population in Colorado will decrease, while the Hispanic population will increase in the next 30 years. White and Hispanic anglers prefer similar species to target and locations in which to fish, but Hispanic anglers are much more likely to keep their catch, which may lead to increased harvest pressure on trout stocks in Colorado in the future.  Colorado is predicted to attract immigrants from California, Texas and Arizona in the next 10 to 20 years. This type of in-migration is unlikely to change demand for species or access in an appreciable way. There may be a slight increase in demand for warm-water game fish such as walleye, but this is likely to be overshadowed by desire for cold-water species found more commonly in Colorado. For more information: For more information about this and other Human Dimensions surveys, please contact Stacy Lischka at stacy.lischka@state.co.us or (303) 291-7279. COLORADO PARKS AND WILDLIFE ▪ 6060 Broadway, Denver, CO, 80216 ▪ (303) 297-1192 ▪ www.wildlife.state.co.us � https://cpw.cvlcollections.org/files/original/f215b75ae427acbfc03e722ff8692154.pdf 795bce7c2411148931a22c62f5f0ca0c PDF Text Text C O L O R A D O P A R K S & W I L D L I F E ANS Boat Interdictions Zebra and Quagga Mussels Invasive mussels are being transported on watercraft! Colorado Parks and Wildlife coordinates a broad multijurisdictional watercraft inspection and decontamination network to protect waters from invasive zebra and quagga mussels and other invasive species. Recreational watercraft is the main vector of introduction for this harmful invader. Colorado is a headwater state and there are no mussels upstream. State certified inspectors repeatedly intercept watercraft infested with mussels. A total of 281 boats with attached adult zebra or quagga mussels have been intercepted coming into Colorado’s waters from out of state at watercraft inspection and decontamination stations. The infested watercraft were intercepted at Barr Lake, Blue Mesa, Boulder Marine, Boulder Reservoir, Boyd Lake, Canon Marine, Carter, Cherry Creek, Chatfield, Clear Creek, Crawford, Denver CPW Office, Dillon, Electra Lake, Eleven Mile, Frisco Bay Marina, Granby, Grand Lake, Grand Junction CPW Office, Great Lakes Marine, Green Mountain, Highline, Horsetooth, Jackson, John Martin, Lathrop, McPhee, Navajo, North Sterling, Pueblo, Ridgway, Rifle Gap, Roadside (SW Colorado), Ruedi, Shadow Mountain, Spinney Mountain, Stagecoach, Steamboat Lake, Strontia Springs, Sweitzer, Taylor Park, Trinidad, Turquoise, Vallecito and Williams Fork. Zebra and Quagga Mussel Positive Interdiction Sites in Colorado cpw.state.co.us �ZEBRA MUSSELS Where are the infested mussel boats coming from? It is often difficult to determine the exact location of infestation due to the frequency of boating use. Also, numerous interceptions are used boat purchases in which the previous boating history is not known. For these reasons, the source of infestation for more than twenty interdicted watercraft is unknown. The remainder of the infested vessels were coming from Arizona, Arkansas, California, Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Mississippi, Missouri, New York, Nevada (Lake Mead), Oklahoma, Ohio, Pennsylvania, Texas, Utah (Lake Powell), Wisconsin, and the Great Lakes. Boat Origin for Zebra and Quagga Mussel Positive Interdictions in Colorado COLORADO PARKS & WILDLIFE 6060 Broadway, Denver, CO 80216 (303) 291-7295 • (303) 297-1192 cpw.state.co.us 1/2020 � https://cpw.cvlcollections.org/files/original/460c892d98dc11518457de067e68d04a.pdf 9833b3e9fea35e77e4abfc9be7e0fe32 PDF Text Text �� https://cpw.cvlcollections.org/files/original/9e4acb8c9225b7679a47d269e446fc33.pdf d318fe9b498865f8d1288e9c2d255a2b PDF Text Text C O L O R A D O P A R K S & W I L D L I F E ANS Fact Sheet AQUATIC NUISANCE SPECIES (ANS) Program OVERVIEW Background The State Aquatic Nuisance Species (ANS) Act was signed into law May 2008. The Act defines ANS as exotic or nonnative aquatic wildlife or any plant species that have been determined to pose a significant threat to the aquatic resources or water infrastructure of the state. The Parks Board passed regulations required by the Act on February 20, 2009 and updated them since that time. The regulations require mandatory watercraft inspection, and if necessary, decontamination of all boats coming from out of state, leaving waters with known ANS and boats entering high-risk waters where inspections are required by the managing entity. The focus of the program is to prevent zebra and quagga mussels and other ANS from infesting Colorado’s water resources and threatening our water storage and distribution systems for municipal, industrial and agricultural use. The Colorado ANS Program is highly effective and a model which other states across the nation are learning from. Program Goal and Successes The goal of the program is to protect the state’s natural resources, outdoor recreation and water supply infrastructure through the prevention of new introductions of costly invasive species, such as zebra or quagga mussels, in Colorado. Western states such as Arizona, Kansas, Nebraska, Oklahoma, South Dakota, and Texas, do not have mandatory ANS prevention programs and continue to become infested with zebra or quagga mussels. Colorado has prevented the introduction of these awful invasive species due to the diligent efforts of watercraft inspection and decontamination staff, as well as monitoring, education and enforcement actions. There has never been an adult zebra or quagga mussel found in Colorado. Pueblo Reservoir was de-listed in January 2017 following 5 years of negative detections. All other reservoirs that initially tested positive in 2008 were de-listed in 2014 after 5 years of negative testing. CPW’s ANS Program has worked to stop the continued inoculation of our waters to invasive mussels being introduced by recreational watercraft. Sampling and Monitoring Sampling and monitoring is a key component to the success of the ANS Program. CPW has sampled 584 “at-risk” waters over the last decade and it was through this sampling program that invasive mussel larvae were first detected in Colorado. While CPW ANS staff monitors the state’s public waters for numerous invasive plant and animal species, the focus of sampling is on early detection of zebra and quagga mussels. There are three sampling protocols that target the three life cycles of mussels. CPW also documents native aquatic plants, mollusks and crayfish while performing monitoring activities for invasive species. Colora d o Pa r ks & Wi ldli Protect Colorad o’s Lands and Wate rs Learn How You Can Stop InvaSIve fe SpeCIeS Information and Outreach CPW and its partner agencies have implemented a comprehensive, multifaceted invasive species public education campaign. Accomplishments include distribution of tens of thousands of printed rack cards, brochures, handouts, DVDs and posted signage at offices, boat ramps and other public access points. Additionally, a media relations campaign has been launched using web, radio, print and television. www.cpw.state.co.u s Working Together: Watercraft Inspection and Decontamination (WID) Watercraft inspection and decontamination is a requirement of the ANS Act and continues to be a key component in preventing the spread of ANS into and within Colorado. CPW coordinates the vast network of WID stations that are operated by CPW, the National Park Service, Larimer County, various municipalities and private industry locations. In total, the state has collectively performed over 4.9 million inspections and 119,814 decontaminations since 2008. cpw.state.co.us �2018 Water Resources Development Act The 2018 Water Resources Development Act (S. 3021) was passed by the 115th Congress and signed into law last October. Section 1170 includes a provision which directs the U.S. Army Corps of Engineers to establish, operate, and maintain new or existing watercraft inspection stations to prevent the spread of aquatic invasive species in the Columbia, Upper Missouri, Upper Colorado, South Platte and Arizona (should be Arkansas) River Basins. The provision also authorizes the Army Corps to assist states with monitoring and rapid response efforts in the case of an infestation of quagga or zebra mussels. Green Mountain Reservoir In August 2017, the U.S. Bureau of Reclamation (BOR) detected quagga mussels in Green Mountain Reservoir. The specimen were genetically confirmed to be quaggas by an independent lab for CPW. Rapid Response was initiated by CPW and began immediately among the multi-jurisdictional partnership. Green Mountain is now listed as “suspect” for quagga mussels and containment is ongoing. Resources are needed for infrastructure, security and staffing to prevent the spread through watercraft. Green Mountain Reservoir within Summit County is owned by the BOR as part of the Upper Colorado River Collection System, and is managed for recreation by the White River National Forest. There were no detections in either 2018 or 2019. If there are no detections in 2020, the reservoir will be de-listed in 2021 per regional standards. Mussel Boat Interceptions Infested mussel boat interceptions continue to skyrocket each year. In total there have been 281 watercraft intercepted with adult zebra or quagga mussels attached since the ANS program began. In 2019, CPW intercepted 86 watercraft infested with zebra or quagga mussels coming in from out of state. In 2018, the state intercepted 51 and in 2017 the state intercepted 26 infested watercraft. This exponential growth in infested boat interceptions is directly related to the growing threat invasive species pose to water infrastructure, natural resources and outdoor recreation. The majority of the intercepted vessels were coming from Lake Powell, the State of Arizona or the Great Lakes. All boats were decontaminated to ensure all mussels were dead, and no mussels were visibly attached. An administrative solution in both the House and Senate is needed to correct the typo is Section 1170 from the nonexistent Arizona River Basin to the Senate’s intent of providing resources to the Arizona River Basin with its headwaters in Colorado. Urge the Army Corp to not delay appropriations or planning in the Upper Colorado or South Platte Basins while the Arizona/Arkansas Basin typo is corrected. Support is needed to gain the fiscal appropriations as authorized in the bill. The Stop the Spread of Invasive Mussels Act of 2019 Senator Bennet, along with Senator Daines and Senator Tester from Montana, introduced the Stop the Spread of Invasive Mussels Act of 2019. The bill authorizes the Secretary of Interior through the Commissioner of Reclamation to provide financial assistance to states or local governments for WID. The bill adds several federal agencies, such as the National Park Service, as a member of the ANS Task Force and provides authorization for all members of the ANS Task Force to conduct WID into and out of federal waters. The bill requires the ANS Task Force to report back on any regulatory changes necessary to implement WID prevention or containment. Finally, the bill corrects the typo in Section 1170 of S.3021 to authorize the Arkansas River Basin. Sponsorship and support is needed to pass this bill. The threat of invasion from zebra and quagga mussels is greater than ever due to numerous new infestations in surrounding states such as Arizona, Kansas, Nebraska, North Dakota, Oklahoma, South Dakota, Texas and Utah. Operating and Financials The Supreme Court ruling in case 13SC996 significantly reduced the source fund for the ANS Program (Tier II Severance Tax) as appropriated in the ANS Act. A broad stakeholder effort was called upon to raise funds and determine long term solutions. CPW redirected agency cash and a USFWS Motorboat Colorado Grant to pay for the 2017 boating season, along with over $1M of partnership funds. The Colorado General Assembly provided funding to the ANS Program through SB17-259 and HB18-1338 to be leveraged with federal dollars and other sources to maintain the program over the 2018–2019 boating seasons. In 2018, the Colorado General Assembly passed the Mussel Free Colorado Act (HB18-1008) to provide a new stable funding source through the creation of an ANS stamp for motorized boats and sailboats—$25 for in state residents and $50 for out of state visitors. The ANS Stamp will provide approximately $2.4M (50% of the need) annual funding to the ANS Program. The bill also increases fines for violations and allows CPW to recoup costs for decontamination of quarantined and impounded vessels. Similar to the 2017 joint resolution on ANS which passed the State Legislature unanimously, the Mussel Free Colorado Act continues to encourage federal governments, specifically the Bureau of Reclamation, U.S. Forest Service and Army Corp of Engineers, to provide the other half of the needed funds for the ANS Program since many of the highest risk waters are federally owned or managed reservoirs. How You Can Help • Contact U.S. Senators and Representatives, and the U.S. Army Corp of Engineers, and encourage them to secure an administrative solution to correct the typo in Section 1170 of S. 3021 (WRDA-2018) changing Arizona River Basin, which does not exist, to Arkansas River Basin, which was the intent of the Senate. • Encourage Congressional delegates and the Army Corp of Engineers to provide fiscal appropriations under Section 1170 of S. 3021 for the Upper Colorado, South Platte and Arkansas River Basins. This funding will be used to provide cost share for WID staff, operations, infrastructure improvements, monitoring and rapid response. • Support the passage of The Stop the Spread of Invasive Mussels Act of 2019. • Urge the U.S. Bureau of Reclamation and the U.S. Forest Service to provide funding to CPW for WID staff, operations and improved infrastructure on waters under their ownership or recreational management. • Inform municipal government, county commissioners, state legislators and federal congressional delegates of the potential economic and social impacts that could occur without ANS preventative measures. COLORADO PARKS & WILDLIFE 6060 Broadway, Denver, CO 80216 (303) 291-7295 • (303) 297-1192 cpw.state.co.us 1/2020 � https://cpw.cvlcollections.org/files/original/4a2043769cf948714aea0dd123000315.pdf 24c1a2b59eb6a5cafdd53821ba09d1eb PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Aquatic Database AQUATIC DATA MANAGEMENT SYSTEM (ADAMAS) Colorado Parks and Wildlife’s Aquatic Database Colorado Parks and Wildlife (CPW) developed a single, centralized computer database - the Aquatic Data Management System (ADAMAS) - to provide current and historic scientific data on the status and trends of the state’s fisheries. ADAMAS, which is updated throughout the year, contains information on over 13,000 lakes and stream segments, and all fish managed by CPW for anglers. The objective was to create a single, quick, reliable and easy-to-access database to help CPW managers enhance angling opportunities and provide information for aquatic scientists and other government agencies researching topics that could benefit Colorado anglers across the state. The actual database is housed on a server in Denver. However the majority of work on the database is conducted by the data analyst within the Aquatic Research Unit at the CPW Fort Collins Research Center. CPW fish biologists and other fishery professionals - including federal agencies, academics and consultants – continually contribute data to ADAMAS. The database holds all the raw data collected annually from surveys across the state and allows CPW biologists, fishery managers and researchers to monitor changes to effectively manage Colorado’s fish resources for anglers. ADAMAS History In the 1980’s, CPW began to standardize survey and data collection methods, allowing for data from all over the state to be stored together. A database would replace paper files, which typically were lost when biologists retired. CPW leadership decided that a statewide, centralized depository for the entire database would benefit everyone. The first rendition of the database, called the Stream and lake Databank, was comprised of only related tables. It has continued to evolve and develop into its present form. The database, now residing on a centralized installation of Microsoft SQL DBMS, is made up of hundreds of related tables. While new data is constantly being added and older data is corrected, the actual database design and structure are also constantly evolving to accommodate new data and assessment techniques. The database currently houses information on over 36,000 individual survey records and over 6 million individual fish, going back all the way to 1875. COLORADO PARKS & WILDLIFE • 1313 Sherman St., Denver, CO 80203 • (303) 297-1192 • cpw.state.co.u �ADAMAS Users  CPW biologists use it to monitor fish populations and manage angling opportunities.  Consulting companies use it to complete federally required environmental assessments.  Aquatic research scientists use it on a wide range of projects, from fish health, and water quality, to the effects of climate change and other environmental issues related to fish.  Water managers use it to inform water management plans and decisions  The general public utilizes the Colorado Fishing Atlas, which links to the ADAMAS database for information on stocking, species distributions and regulations.  Scientists who make a formal data request to the data analyst (who coordinates the review and approval of all requests and compiles the data necessary. ADAMAS Contributors Eighteen area biologists, four senior biologists, four Aquatic Species Conservation biologists and seven aquatic research scientists contribute data to the database annually. Scientific Collection Permit holders must also submit their data for inclusion into the database in order for any subsequent permits to be processed. This includes federal agencies, academic institutions and private consultants. ADAMAS Support A data analyst within CPW's Aquatic Research Section manages ADAMAS, updates and organizes the information, provides technical support for using the data, and coordinates the data request process. The analyst also coordinates the development of new software and provides information to professional fishery scientists focusing on fish health, adaption to climate change and other environmental factors. ADAMAS Funding: A Sportfish Restoration Program Grant from the U.S. Fish and Wildlife Service and CPW. � https://cpw.cvlcollections.org/files/original/c41ec16c27f76b616f1ed481cd8558c1.pdf ef049897b6e2a97cb7257940da02b4cf PDF Text Text �� https://cpw.cvlcollections.org/files/original/f84705cf55f1bd024dd26ea917d31cc1.pdf b872c5ec2dbdc345834aa49d483918a0 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Blue Mesa Lake Trout ACHIEVING LAKE TROUT AND KOKANEE FISHERY OBJECTIVES THROUGH LAKE TROUT HARVEST Can trophy lake trout and kokanee be maintained through increased harvest of small lake trout? Kokanee fry survival has declined since lake trout began naturally reproducing within Blue Mesa Reservoir beginning in the early 1990's. This decline was due to higher predation from the expanding and now larger population of predatory-sized lake trout (Figure 1). Anglers value opportunities to fish for both kokanee and lake trout. Kokanee provide the greatest draw for overall catch and harvest while lake trout provide the greatest draw for their trophy potential. Lake trout over 50 pounds and 44 inches in length have been caught. However, lake trout require plentiful kokanee as prey to achieve such large size (Figure 2). Improving kokanee fry survival by reducing predation from small lake trout is necessary for maintaining abundant kokanee and associated benefits to anglers seeking to catch and eat kokanee or seeking trophy lake trout. Recent study: managing for coexistence of kokanee and trophy lake trout Unsustainable levels of predation by lake trout can lead to rapid declines in kokanee abundance and in lake trout growth and body condition. Immediately following a 90% decline in kokanee abundance during the 2000’s, CPW initiated fall netting efforts for lake trout in 2009 to recover kokanee while still providing for a trophy lake trout fishery. Additional harvest of lake trout is needed to achieve these management objectives. Recent research demonstrated that increased removal of primarily small, young lake trout could improve kokanee fry survival, the overall abundance of kokanee, and produce more trophy lake trout. It is possible that this increased harvest could be achieved through a lake trout harvest incentive program, but may require additional netting if angler harvest is not sufficient. Figure 1. Reconstructed population trajectory of predatorysized lake trout over time (years) based on abundance estimates from netting (SPIN) and mark-recapture surveys. A harvest incentive tournament can lead to improved angler involvement and efficient fisheries management: Fall netting by CPW supplemented angler harvest by removing ~1,200 lake trout annually from 2009 through 2017 while returning trophy-sized lake trout to the water. Angler harvest averaged ~6,000 lake trout annually over this period (Figure 3). As a result of these joint efforts, the abundance of predatory-sized lake trout has decreased recently (Figure 1) and kokanee survival and abundance has improved. However, recent lake trout monitoring surveys indicate that numerous small lake trout are now growing larger and expected to switch to preying on fish. CPW feels there is an opportunity to further encourage angler harvest through a lake trout harvest incentive program which could more efficiently remove enough small lake trout such that netting would not be required. Ninety-six percent of lake trout harvested by anglers and netted by CPW were smaller than 24 inches in length. Figure 2. Average number of kokanee (KOK) per predatory-sized lake trout (MAC) present in Blue Mesa Reservoir over time (years) in relation to when state-record fish were caught. Lake trout harvest incentive tournament details:  Only heads from lake trout less than 24 inches will be accepted.  Tournament dates: February 1 st through July 31st, 2020.  Prizes for most heads turned in: $1,000 for most, $500 second most, $250 third most.  Prize for each tagged fish turned in: $250 (tags are not visible).  Twenty $200 prizes randomly selected with one chance for each head turned in.  Head drop off locations: Iola, Elk Creek, and Lake Fork Marinas; Gunnison and Montrose CPW offices.  Call (970) 641-7070 or email dan.brauch@state.co.us for more information. Figure 3. Estimated total harvest of lake trout (MAC) during different periods by anglers over time (years) in relation to CPW fall netting. References: Hansen, A.G., and D. Brauch. In review. Long-term population dynamics of lake trout in Blue Mesa Reservoir, Colorado: guidance for an angler harvest incentive program. CPW report. Pate, W.M., B.M. Johnson, J.M. Lepak, and D. Brauch. 2014. Managing for coexistence of kokanee and trophy lake trout in a montane reservoir. North American Journal of Fisheries Management 34:908–922. COLORADO PARKS & WILDLIFE • 300 W. New York Ave., Gunnison, CO 81230 • (970) 641-7070 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/54b0637d38234e14c3babd1c7283b6f5.pdf ceae0bd0614c51e321eb2aa81ff3e646 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Brown Trout Life History EVALUATING BROWN TROUT POPULATION STRUCTURE AND LIFE HISTORY IN THE SOUTH PLATTE RIVER Brown Trout Ecology Brown Trout are native to Europe, Western Asia, and Northern Africa, and have been introduced to every continent except Antarctica. Across their native and introduced ranges, Brown Trout show a large diversity in life-history traits. For example, some Brown Trout stay within a small section of stream their entire life. Some populations consist of fish that spawn only once, while in other populations, fish spawn multiple times over their lifetimes. There are also populations that are anadromous, where fish move up freshwater rivers from the ocean to spawn, as well as adfluvial populations, where fish migrate between rivers and lakes. Along with these differences in life history, the physical appearance of Brown Trout varies greatly, which could be related to genetics, habitat use, diet, and fish age, among other factors. However, the connection between life-history traits, factors affecting physical appearance, and management in North America is not well studied. Black (top), intermediate (middle), and red (bottom) spotting patterns of Brown Trout from the Middle fork of the South Platte River. Brown Trout were first introduced to the United States in 1883, and subsequently introduced into Colorado in 1890. Different source populations were used to establish these wild Brown Trout fisheries, including lake populations from Scotland and river populations from Germany. Brown trout populations in Colorado are generally considered a mix of these two, and exhibit physical and behavioral characteristics of both as part of their life histories. Understanding Brown Trout life history is an important aspect of managing these populations throughout the state. Brown Trout in the South Platte River The Brown Trout population in the Middle Fork of the South Platte River near Hartsel is of interest to both anglers and mangers due to the unique angling opportunities provided by both Spinney Mountain Reservoir and the state wildlife areas along the South Platte River. Between 2006 and 2011, a stream restoration project was completed in a small section of the Middle Fork of the South Platte to create deeper pools for overwinter habitat and to hold big fish throughout the rest of the year. Between 2013 and 2016, CPW biologists and researchers conducted a tagging study to investigate habitat use by Brown Trout throughout the river. Fish were tagged with passive integrated transponder (PIT) tags containing a unique identification number that can be used to track the location of fish through physical recaptures and scanning during population estimate, and by river-spanning COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us �antennas placed in the river that can detect the tags when the fish move past their location. These antennas record the date and time when movements are made year-round. Over the course of the study, three Brown Trout spotting patterns were identified: those with only black spots, those with red spots, and an intermediate spotting pattern between the two. To determine if spotting pattern explained observed movement patterns or the life history of the Brown Trout population in the Middle Fork of the South Platte River, additional data was collected in 2016, including stable isotopes, a technique used to identify chemical signatures in the fish tissue and characterize their diets and where feeding occurred, scales for aging fish, and genetic samples. South Platte River Brown Trout Population Structure and Life History A total of 1,259 Brown Trout were PIT-tagged over the three year study. Brown Trout with typically black spots and larger sizes moved longer distances, crossing all four of the stationary antennae at least once during the study. Although some PIT-tagged fish made long-distance movements, most moved less than 9 miles, with the majority of the fish moving 1 mile or less, suggesting many were river residents. Larger movements were made in the fall (September through October) as well as the spring (March through May). Fall movements occurred during the Brown Trout spawning period, whereas spring movements occurred when the ice was melting. Brown Trout primarily used the section of river at the upstream end of the study area, and Spinney Mountain Reservoir. When Brown Trout chose to move, they generally moved between these two locations fairly quickly, bypassing the habitat in between, including the deep pools in the restoration section, to reach favorable spawning areas or overwinter habitat in the reservoir. Brown Trout with black spots were older than Brown Trout with red spots, and fish with an intermediate spotting pattern fell between the two, suggesting spotting pattern changed as fish got older. Isotope data indicated that black spotted fish and red spotted fish each eat different foods and reside in different parts of the system. Black spotted fish spend most of their time within the reservoir, entering the river to spawn in the fall, and the red spotted fish live primarily within the river. Fish with an intermediate spotting pattern are likely transitioning from life in the river to life in the reservoir as they get older. Genetic testing indicated that the Brown Trout with black spots, red spots, and the intermediate spotting Average age (95% confidence intervals) of Brown Trout with pattern were related and form one adfluvial Brown black, intermediate, and red spotting patterns from the Middle Fork of the South Platte River. Trout population. Brown Trout in the Middle Fork of the South Platte River rely on both the river and the reservoir to complete parts of their life history (e.g., spawning and juvenile rearing versus overwinter habitat and growth), and change spotting patterns as the fish age and use these different habitats. Management of Brown Trout This study allowed biologists to better understand the life history of Brown Trout in the South Platte River. Based on the suite of data collected, these Brown Trout represent one population with an adfluvial life history incorporating characteristics of lake and river source populations historically used to establish Brown Trout in Colorado and North America. The connection between the reservoir and the upstream spawning habitat is important to the life history of the Brown Trout in this system, providing habitats needed to complete different parts of their life cycle. This information will help inform management of the fish in both the Middle Fork of the South Platte River and Spinney Mountain Reservoir, promoting their persistence, and ultimately providing more angling opportunities in both systems. Additionally, knowledge of the life history can be used to guide future river restoration activities in this and other rivers around the state to maximize their success. Associated Literature Avila, B. W., E. R. Fetherman, M. C. Kondratieff, E. E. Richer, D. A. Kowalski, M. R. Baerwald, A. Goodbla, and J. Spohn. In preparation. Brown Trout population structure and life history in the South Platte River, Colorado. COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/2577a24426f85cc5bf1957ef02899a8f.pdf c88b3efce30a00c8c671ff495b370edf PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Dual Disease Resistance in Rainbow Trout EVAUATING RESISTANCE TO BACTERIAL COLDWATER DISEASE AND WHIRLING DISEASE IN COLORADO’S TROUT Bacterial Coldwater Disease (BCWD) Bacterial coldwater disease (BCWD) is caused by the bacterium Flavobacterium psychrophilum. Found worldwide, BCWD causes significant complications and death in hatchery trout populations. Outbreaks typically occur at temperatures between 39 and 50F. Infected fish show a broad range of clinical disease signs including lesions, spiral swimming, “black tail”, spinal deformities, and pale or necrotic gills. Mortality can be high if left untreated, and antibiotics are commonly used to treat BCWD. As an alternative, the USDA National Center for Cool and Cold Water Aquaculture (NCCWA) developed a Rainbow Trout strain that is resistant to F. psychrophilum. With the help of Utah Division of Wildlife Resources, psychrophilum-resistant Rainbow Trout (PRR) were incorporated into the CPW hatchery system to help manage BCWD outbreaks. Lesion caused by F. psychrophilum infection Whirling Disease (WD) Whirling disease (WD) is caused by the parasite Myxobolus cerebralis. Spinal deformity, M. cerebralis infection Signs of infection include skeletal deformities, “black tail”, and “whirling” or spiral swimming. WD cannot be treated, and susceptible fish typically die within their first year. M. cerebralis has a complex multi-stage life cycle, making it extremely difficult to remove from aquatic environments. One option for management is to use M. cerebralis-resistant fish. The Hofer strain is genetically resistant to M. cerebralis, however, it is domesticated and shows reduced survival in the wild. To increase survival, CPW crossed the Hofer with wild Rainbow Trout strains. The resulting crosses (HxC, Hofer by Colorado River Rainbow; HxH, Hofer by Harrison Lake Rainbow) are resistant to M. cerebralis, and survive and reproduce in the wild. Stocking M. cerebralis-resistant Rainbow Trout has helped reduce WD in aquatic systems throughout Colorado. Evaluating Dual Resistance via Dual Exposure to BCWD and WD CPW uses the PRR to reduce mortality in the hatchery due to F. psychrophilum outbreaks. However, it is unknown if the PRR are resistant to M. cerebralis. Stocking PRRs with no resistance to M. cerebralis could result in high losses from WD, as well as increased M. cerebralis prevalence. Conversely, although resistant to M. cerebralis, the HxH shows increased mortality in the hatchery during BCWD outbreaks. This study examined if crossing the PRR with the HxH resulted in fish that are genetically resistant to both F. psychrophilum and M. cerebralis. Dual exposure laboratory, Colorado State University COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us �Injecting fish with F. psychrophilum The PRR, HxH, and HHP, the first generation cross between the PRR and HxH, were used for the dual exposure experiment. To test genetic resistance to both pathogens, fish were exposed to F. psychrophilum, M. cerebralis, or both. Fish were exposed to F. psychrophilum using injections under the skin, and to M. cerebralis using bath exposure to triactinomyxons, the waterborne infectious stage of the parasite. Mortality from F. psychrophilum occurs within 28 days of exposure, and was the first measureable endpoint of the experiment. Fish were then reared for six months to allow development of myxospores, the countable form of M. cerebralis in fish, and disease signs and myxospore counts were obtained from the fish remaining at the end of the experiment. The PRR experienced the lowest cumulative mortality when exposed to F. psychrophilum, showing that it was more resistant to F. psychrophilum than either the HxH or HHP. However, with higher myxospore counts than either the HxH or HHP, the PRR did not show any resistance to M. cerebralis. The HxH had much lower myxospore counts and was more resistant to M. cerebralis than the PRR. However, as had been observed in the hatchery, the HxH did not exhibit any resistance to F. psychrophilum. The myxospore counts for the HHP were intermediate to those of the HxH and PRR, and the HHP experienced high cumulative mortality when exposed to F. psychrophilum, showing that it had not gained resistance to F. psychrophilum from the PRR. Coinfection with F. psychrophilum and M. cerebralis increased mortality in the PRR, HxH, and HHP compared to single-pathogen exposure. Left: Cumulative percent mortality (CPM) for the HHP, HxH, and PRR across six treatments, 1) control (no pathogen exposure), 2) F. psychrohilum only (Fp), 3) exposure to F. psychrohilum followed by exposure to M. cerebralis (Fp Mc), 4) M. cerebralis only (Mc), 5) exposure to M. cerebralis followed by exposure to F. psychrophilum (Mc Fp), and 6) mock injection with TYES media (TYES). Right: Myxospores per fish head as a measure of M. cerebralis infection for the HHP, HxH, and PRR in each of the six treatments at the end of the experiment. Management Implications The results of this experiment suggest that it was not possible to create fish that are resistant to both F. psychrophilum and M. cerebralis using the HxH and PRR. In a follow up experiment, we exposed pure strains and their crosses to F. psychrophilum and found that the first generation cross between the Harrison Lake Rainbow Trout and the PRR showed reduced mortality and resistance to F. psychrophilum. Therefore, it may be possible to produce Rainbow Trout that are resistant to both pathogens, though their resistance to M. cerebralis still needs to be evaluated. More research is needed to determine if other strains not included in these experiments can be used to create fish resistant to both pathogens. Until then, hatchery outbreaks of BCWD in susceptible fish such as the HxH can be reduced by maintaining high water quality, flows, and reduced densities to prevent stressful rearing conditions. Using PRRs in hatcheries where F. psychrophilum outbreaks are common will help reduce mortality from BCWD on the unit, but due to their susceptibility to WD, these fish should not be stocked in aquatic systems in which M. cerebralis is established. Associated Literature Fetherman, E. R., B. Neuschwanger, B. W. Avila, and T. B. Riepe. 2020. Sport Fish Research Studies. Annual Report. Colorado Parks and Wildlife, Aquatic Research Section. Fort Collins, Colorado. COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/30da1495064c352dac20ff058539b04f.pdf 90a326d115e70e34e6d2bb086c99d358 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Electric Fish Barrier Research Background There are over 105,000 irrigation structures on rivers and streams across Colorado, most in fish bearing waters. Fish loss in irrigation canals is known to be a large problem in the western U.S. but the impact on fish populations in Colorado is unknown. The South Canal is an irrigation ditch near Montrose, Colorado that diverts an average of 857 cubic feet per second from March to November from the Gunnison River for agriculture. The construction of a hydropower plant was expected to increase mortality of fish in the canal so an electric fish barrier was installed at the diversion structure in 2012. Research Objectives The objective of this work is to evaluate if electric fish barrier technology can reduce the loss of sport fish in irrigation canals in Colorado by monitoring fish populations in the South Canal and documenting tagged fish that cross the barrier. Electric Fish Barrier The fish barrier was operational before the 2013 irrigation season. It consists of a series of vertically suspended electrodes across the east portal of the Gunnison Tunnel. The system uses pulsed direct current (DC) to deter fish. DC is the safest type of electrical current for fish and has been shown to repel fish without injuring them. The barrier was designed to exclude broodstock rainbow and brown trout with a field strength of 1 volt per inch, a relatively low power setting for electric fish barrier designs in the United States. Pulsed DC current is size-selective; it affects larger fish more than smaller fish. Approach A total of 23,031 fish from 3 to 29 inches in length were tagged and released in the Gunnison River above the barrier. Fish were removed from the canal before the barrier was operational and annual electrofishing surveys were used to estimate fish populations and look for tagged fish. COLORADO PARKS & WILDLIFE • 6060 Broadway, Denver, CO, 80216 • (303) 297-1192 • www.cpw.state.co.us �Results and Conclusions  The electric barrier successfully prevents large fish from entering the canal and being lost to the Gunnison River population.  No fish larger than 16 inches in length have passed the barrier, and only four fish larger than 12 inches have passed through the barrier.  Smaller age 1, age 2, and some age 3 fish can pass through the barrier.  The barrier prevents 26-71% of all of the spawning sized fish from entering the canal and being lost to the Gunnison River population.  The number of brown trout in the canal declined after the barrier, but growth and survival of smaller fish that pass the barrier maintain a stable fish population.  The electric barrier successfully protects larger brood fish in the Gunnison River but more work is needed to see if it can be adjusted to better exclude smaller fish. 4,000 3,500 Brown Trout 3,000 Population Estimate Rainbow Trout 2,500 2,000 1,500 1,000 500 0 Oct 2011 Mar 2013 Oct 2013 Jul 2014 Oct 2014 Brown trout numbers have declined since the barrier was built in 2012 but small fish that pass into the canal maintain a stable trout population. 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Fish bioenergetics is the study of how factors such as metabolism, water temperature, and quality of prey regulate the ability of fish to convert energy from food into body mass or growth in weight. Much effort has been devoted to developing models that describe the bioenergetic characteristics of different species of sport fish found in Colorado’s lakes and reservoirs and elsewhere. These models help biologists address a number of critical fisheries management questions and guide efforts to improve growth within fish populations and ultimately fishery quality. For example, fish bioenergetics is useful for answering: o What limits fish growth the most: temperature, prey availability, or the quality of prey? o How much prey do predators eat? Is it too much, or can prey populations handle higher levels of predation? o What is the optimal number of fish to stock based on the available food supply in a lake or reservoir? Caloric content of fish: the currency of bioenergetics Knowing the “energy richness” of fish is important because it is an indicator of fish health, prey quality, and because energy is the common currency used to convert the amount of food eaten by a fish into weight gain or loss in bioenergetics models; this approach is similar to counting calories in the foods we eat and tracking the fate of those calories once ingested. Many factors influence the caloric content of fish, and it is possible for the same species to differ among lakes. In this study, we estimated the caloric content (number of calories in one gram of fish tissue) of key predator and prey fish found in Colorado’s coldwater reservoirs to improve the applicability of bioenergetics models to CPW’s management of these species. The average caloric content of different species examined is shown in the figure below: The most striking observation was the high caloric content of kokanee salmon, which was 2-fold or more greater on average than the other species of prey fish available to predators. For example, a lake trout in Blue Mesa Reservoir would need to eat two or three rainbow trout, white suckers, or yellow perch to obtain the same amount of energy gained from eating a single kokanee of equal size. This observation also indicates that kokanee are more efficient consumers of zooplankton, a primary food source for prey fish in our fluctuating coldwater reservoirs. Thus, kokanee help maximize fishery productivity. Overall, this research highlights the irreplaceable role kokanee play as a sport fish for anglers and as energy rich prey fish for predators in Colorado’s reservoir food webs. Managing for populations of healthy, abundant kokanee ensures the long-term maintenance of CPW’s kokanee stocking program and benefits therein to anglers seeking to catch and eat kokanee or seeking to catch predatory sport fish like lake trout that rely on plentiful kokanee for supporting high feeding and growth. Associated peer-reviewed publication: Johnson, B.M., W.M. Pate, and A.G. Hansen. In press. Energy density and dry matter content in fish: new observations and an evaluation of some empirical models. Transactions of the American Fisheries Society. COLORADO PARKS & WILDLIFE • 317 W. Prospect Rd., Fort Collins, CO 80526 • (970) 472-4432 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/791ff8c2337cef651ab3251e9d56d070.pdf 28b7830f38d58eed59e4e8c0c4b05a6c PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Fish Passage at River Structures RESEARCH AND DESIGN GUIDELINES Introduction Instream structures, such as culverts, water diversions and dams, can negatively affect fish by fragmenting populations, reducing migratory ranges, and limiting access to habitat for spawning, feeding and refugia. Many rivers in Colorado contain man-made structures that create partial (obstacles) or complete barriers depending on the fish species and life stage. Habitat fragmentation associated with instream barriers is a serious threat to Colorado’s Species of Greatest Conservation Need (SGCN) and sport fisheries. Therefore, it is important that fisheries managers (A) identify and evaluate the influence of instream structures on fish populations. Fish Passage Research Objectives The primary goal of fish passage research is to restore connectivity in fragmented river systems by: (1) evaluating the effectiveness of existing fishways; (2) evaluating the barrierpotential of common river structures; and (3) establishing fish swim performance criteria for native and sport fishes. Current Fish Passage Research Projects Active fish passage research projects include: (1) evaluation of native fish passage at existing fishways located on Front Range transition zone streams; (2) evaluation of fish passage at instream whitewater park structures; (3) laboratory studies to develop fish swim and jump performance criteria for Colorado fishes where data is lacking; and (4) development of new techniques and technologies for investigating fish movement and passage in rivers. (B) Fishway Design Fishways, or “fish ladders”, are engineered structures designed to facilitate passage around an obstacle or barrier. Fishways attempt to incorporate species- and life stagespecific swimming and jumping abilities into designs. Common elements of successful fishways include: (1) low velocity pathways that do not exceed burst speeds or endurance capabilities for target species (Figure A); (2) water depths that do not limit swimming performance (Figure B); (3) vertical drops that do not exceed the jumping ability for target species - note that many species native to Colorado do not exhibit jumping behaviors (Figure C); (4) sufficient attraction flow, or the flow that emanates from a fishway entrance, to ensure that fish can locate the fishway; and (5) maintenance of the above design elements over the expected range of streamflows. (C) COLORADO PARKS & WILDLIFE • 1313 Sherman St., Denver, CO 80203 • (303) 297-1192 • cpw.state.co.us �Fishway Examples Some examples of successful fishways include engineered rock ramps (Figure D), constructed riffles (Figure E), and vertical slot fishways (Figure F). Each type of fishway has advantages and disadvantages related to which fish species and life stages are present and the conditions of the project site. Engineered Rock Ramp Constructed Riffle Vertical Slot Diversion Crest Piney Creek, Wyoming Fossil Creek Reservoir Inlet Diversion, Cache la Poudre River (D) Rock Weirs CCC Ditch, San Miguel River (E) (F) Aquatic Habitat Types From the high-gradient, boulder-dominated, step-pool channels of snowmelt fed mountain streams to the lowgradient, well-vegetated, pool-riffle rivers of the eastern plains to the majestic, vertically-confined canyons on the arid Colorado Plateau, aquatic habitats in Colorado are as diverse as the geographic regions where they are found. Native Colorado fishes have unique morphological characteristics that are adapted to the natural conditions found in each aquatic habitat type. These adaptations affect the swimming abilities of fish, influencing how they move through and use diverse habitats. Fisheries managers must take the diversity of fish species into consideration when evaluating river structures and designing fishways. Fish Swimming Performance by Family Family Name Percidae (Perches) SGCN (#) Fundulidae (Topminnows) Cottidae (Sculpin) Ictaluridae (Catfish) Cyprinidae (Minnows) Catostomidae (Suckers) Centrarchidae (Sunfish) All illustrations of fish © Joseph R. Tomelleri 3 Prolonged Speed (ft/s) 0.4 - 1.2 Burst Speed (ft/s) NA - 2.4 Jump Height (ft) 0* Habitat Types EP 1 0 1 13 5 1 1.3 - 1.6 1.4 - 1.7 1.3 - 2.0 1.3 - 2.4 1.3 - 2.5 1.1 - 2.9 2.6 - 3.4 3.3 - 3.9 2.0 - NA 2.4 - 4.4 2.2 - 3.2 2.6 - NA 0.1 - 0.2 0* NA - 0.2 0* - 0.5 NA - 0.8 0.4 - NA EP CP, MS EP, TZ CP, EP, MS, RG, TZ CP, EP, MS, RG, TZ EP Salmonidae (Trout) 3 2.3 - 4.0 4.5 - 7.5 1.0 - 7.0 MS, RG, TZ SGCN = Species of Greatest Conservation Need, # of species/subspecies; * = fish species does not exhibit jumping behavior; NA = data were not available; CP = Colorado Plateau, EP = Eastern Plains, MS = Mountain Streams, RG = Rio Grande; TZ = Transition Zone The values reported above are summarized from multiple species within each family and are intended to support passage for juvenile life stages. Swim speeds and jumping abilities within species are size dependent. Species-specific performance criteria should be used whenever possible. The selection of target species for individual projects should be based on the management objectives for the site in question. Consultation with the local Area Aquatic Biologist at CPW is strongly encouraged during the early planning stages for any fish passage project in Colorado. The information in this fact sheet is based on the best available data and knowledge, but is subject to revision as more information becomes available. COLORADO PARKS & WILDLIFE • 1313 Sherman St., Denver, CO 80203 • (303) 297-1192 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/c60fcc7f250f17175d2f2ecc3b317b68.pdf 3514930cf864d79473c73f92f237d239 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Gill Lice in Colorado NOVEMBER 2018 Gill Lice Gill lice are an external parasite of trout and salmon found throughout the US including Colorado. These parasites have the potential to negatively influence salmonid fisheries throughout Colorado because they can impair fish growth, behavior and survival. To date, only one species of gill lice has been identified in Colorado, Salmincola californiensis. This species of gill lice is known to infect kokanee salmon, cutthroat trout, and rainbow trout throughout the state. No infection of gill lice has been confirmed on any other species of fish in Colorado. CPW continues to work on potential management actions or other approaches to minimize the negative impacts of gill lice on Colorado’s valuable native and sport fisheries. Specifically, CPW is attempting to: • Assess the current infection presence and intensity of gill lice. • Determine the extent of negative effects on fish populations throughout the state. • Identify conditions leading to high levels of gill lice. • Identify potential management actions and approaches to reduce negative impacts on fisheries. Gill Lice Background Gill lice (of the genus Salmincola), are a parasitic zooplankton that generally attach to the gills, mouths and fins of salmonid fishes (e.g., salmon, trout). Since the initiation of the gill lice project in Colorado in 2012, gill lice have been identified on cutthroat trout, rainbow trout and kokanee salmon. It is important to note that gill lice infestation does not make fish unsafe for consumption. Heavy gill lice infections can prevent fish from breathing normally, inhibiting oxygen uptake through damaged gill filaments. Gill lice infestations can also negatively affect fish behavior, immune system function, growth, warm water tolerance and ultimately survival. Gill lice were first reported in Colorado in the early 1900’s. Until relatively recently, the negative effects associated with gill lice on fish were limited to infestations in hatcheries, though the presence of gill lice in some Colorado water bodies outside of hatcheries was known. However, more recently, anecdotal evidence has linked declines in fish populations with the occurrence of gill lice, and it is important to understand these more recent observations. Specifically, kokanee salmon populations in many lakes throughout the west have completely collapsed after becoming infected with gill lice. COLORADO PARKS & WILDLIFE • 1313 Sherman, Suite 618, Denver, CO 80203 • (303) 866-3437 • cpw.state.co.us �Kokanee salmon and native cutthroat trout are ecologically and economically important fish species in Colorado that have experienced recent population declines. These populations are especially important to conserve, preserve and protect. Gill lice research is focused on identifying and developing options for limiting the spread of gill lice to these populations as well as minimizing negative effects from gill lice in native fish populations where gill lice are already present. This research will help maintain and potentially enhance these valuable fisheries and the ecologically and economically important fish species that support them. CPW research on gill lice is especially important because controlling or eliminating the parasite in wild fish populations is currently diffic ult or impossible, and this project is aimed at gaining an understanding of gill lice to address this challenge and present viable management options to reduce negative impacts associated with gill lice spread. Current CPW Gill Lice Research Projects • • • • Working with researchers and students at Colorado State University (CSU) to improve the understanding of how gill lice affect trout and salmon in the state. Investigating the current and potential consequences of gill lice on kokanee salmon and native cutthroat trout. Investigating the effects of fish size and stress on infection rates to determine potential management options. Fish stressed by high population density, low water levels, warm water temperatures or spawning may be more susceptible to gill lice. Completing experiments to determine if some fish species are more likely to become infected with gill lice. Anglers Can Help! If you would like to report gill lice in Colorado, please e-mail estevan.vigil@state.co.us or george.schisler@state.co.us at CPW. Please include information about: Species of fish caught? Where was the fish caught? How long was the fish? What parts of the fish had gill lice? Any photos. COLORADO PARKS & WILDLIFE • 1313 Sherman, Suite 618, Denver, CO 80203 • (303) 866-3437 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/c95ace870822c077ecd35815eb7952b2.pdf 89376b161cce08221286aa48471a140f PDF Text Text � https://cpw.cvlcollections.org/files/original/5827b9ce8cda1b3bf46b71d4c92a3eae.pdf 68bb3a8e5802d8ce418009a5ac8b6be4 PDF Text Text � https://cpw.cvlcollections.org/files/original/360d8200bf337afe2e96cb1615ab266e.pdf 2f914de19404675093f6939bfd896658 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Lake Trout Population Monitoring RAPID ASSESSMENT OF LAKE TROUT POPULATION SIZE IN LAKES AND RESERVOIRS How are lake trout populations monitored? Lake trout are top predators, reproduce naturally, and are important sport and food fish for anglers in Colorado’s lakes and reservoirs. Keeping close tabs on their abundance and size structure is necessary for assessing the appropriateness of harvest regulations, ensuring lake trout remain in balance with prey fish populations, and determining whether management goals are achieved. However, estimating the abundance of lake trout in our large coldwater reservoirs at the frequency needed to inform management using conventional methods such as mark-recapture is impractical. Thus, CPW researchers and biologists evaluated the utility of “Summer Profundal Index Netting” (SPIN) for application to lake trout in Colorado beginning in 2011. Developed by the Ontario Ministry of Natural Resources, SPIN is a standardized gill netting method for estimating the density of lake trout ≥12 inches over a 1-2 week period. Colorado has since adopted SPIN for monitoring lake trout populations in Blue Mesa Reservoir, Grand Lake, Lake Granby, and Taylor Park Reservoir. Survey design, implementation, and results: Standard gill nets specific to this protocol are set for two hours during daylight along the bottom in random orientation when surface temperatures exceed 64°F. You may see these nets being set or pulled at these lakes by CPW personnel during the summer months. The number of sets depends on the surface area of the lake or reservoir. Set locations cover depth intervals of 6-32 ft, 32-64 ft, 64-96 ft, 96-128 ft, 128-192 ft, 192-256 ft, and >256 ft. Sampling is also conducted in different portions of the lake or reservoir if necessary to account for differences in lake trout habitat. Catch rates of lake trout in the gill nets set in Colorado systems are compared to catch rates of lake trout in the same type of gill nets in other water bodies where estimates of lake trout density were available. The advantage of this method is the use of data from numerous other systems as a calibration tool to quantify lake trout densities and abundances in Colorado. Please see Lepak (2011) and Hansen (2018) for additional information. Management implications: Results from each SPIN survey conducted to date shows that lake trout density varies 7-fold across study systems. This indicates that processes governing the productivity of lake trout vary or operate differently in each lake or reservoir. Thus, management plans and corresponding harvest regulations must be tailored to each individual lake trout population in order to achieve desired goals for the fishery. Map of Blue Mesa Reservoir showing gill net set locations (N = 83 dots) and the associated depth interval sampled (colors) during the 2016 SPIN survey: Summary data from each SPIN survey conducted to date. Asterisks indicate the presence of Mysis shrimp in the body of water. Survey year Number of lake trout caught Mean length (inches) Density (fish/acre) Total area surveyed (ha) Abundance estimate Blue Mesa 81 129 17.2 4.51 7,559 34,071 Grand Lake* 36 87 16.5 5.14 477 2,452 Taylor Park* 36 271 16.4 7.94 1,507 11,950 Blue Mesa 81 211 16.7 3.18 8,424 26,753 Lake Granby* 71 501 16.4 23.17 6,870 159,193 Blue Mesa 83 180 17.2 2.89 8,424 24,368 Grand Lake* 36 109 17.2 6.56 477 3,131 Blue Mesa 95 313 16.3 4.60 6,496 29,857 2011 2013 2014 References: Hansen, A.G. 2018. Summer profundal index netting for tracking trends in the abundance of lake trout in coldwater lakes and reservoirs of Colorado: results from 2018. Internal CPW report. 6 pages. Lepak, J.M. 2011. Evaluating summer profundal index netting (SPIN) as a standardized quantitative method for assessing lake trout populations. Internal CPW report. 10 pages. Number of gill net sets Lake or reservoir 2016 2018 COLORADO PARKS & WILDLIFE • 317 W. Prospect Rd., Fort Collins, CO 80526 • (970) 472-4432 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/71ac50ed842107ac6c6ae6b0692a9fc2.pdf e1776d59f76ee0df746632d7554c9537 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Managing Mercury in Sport Fish TRIPLOID WALLEYE BIOACCUMULATE LESS MERCURY Mercury and Colorado Sport Fish According to the U.S. Food and Drug Administration, fish are part of a healthy diet, providing lean protein, healthy omega-3 fatty acids, iron, and more vitamin B12 and vitamin D than any other food. Although fish are an excellent source of protein, integration of mercury into lake and stream food webs results in traces of mercury being present in fish, sometimes at levels that present health concerns to people who consume fish regularly. Because mercury levels increase as you move up the food chain (i.e., ‘bioaccumulate’), concentrations are highest in top predators such as walleye. Through monitoring and research, both the Colorado Department of Public Health and Environment and Colorado Parks and Wildlife (CPW) work to help anglers maximize the benefits of consuming fish while protecting themselves and their families from mercury in the environment. How does mercury get here? Mercury is released into the atmosphere through a variety of natural (e.g., forest fires) and human-caused (e.g., burning fossil fuels) pathways. Mercury can then disperse far from its source before being deposited into lakes and streams, making it difficult to control. While national and global actions to reduce mercury pollution are essential, strategies at the local scale are needed to protect the health of Colorado’s anglers. A recent study on Narraguinnep Reservoir (southwest Colorado) conducted by CPW and researchers from Colorado State University found that ‘triploid’ walleye (have a third set of chromosomes and cannot reproduce naturally) stocked by CPW had 22-24% lower mercury concentrations on average than their naturally-reproducing ‘diploid’ counterparts (have a normal number of chromosomes). This study revealed that stocking triploid fish alone or in tandem with other mitigation strategies can lead to safer fish for anglers to eat. Map of Colorado showing waters with a current fish consumption advisory (red balloons) versus those without (green). Interactive map accessible here: https://cdphe.colorado.gov/waterquality/clean-water/rivers-lakes-andstreams/fish-consumption Why do triploid walleye bioaccumulate less mercury? The answer begins with how and why triploid walleye are produced by CPW. Every spring CPW collects eggs from wild populations of walleye to raise in the hatchery and stock fry into reservoirs that support high angling pressure. Some of these eggs are specially treated to produce triploids. Triploidy is induced by placing fertilized eggs into a hydrostatic pressure chamber for a defined period (see images to right). As a result, the fry that hatch retain an extra set of chromosomes, rendering them incapable of naturally-reproducing over their lifespan. Because triploid walleye are sterile, they can be stocked to support sport fisheries in strategic locations where natural reproduction is not wanted. As this new research discovered, the inability of triploid walleye to reproduce also affects their mercury levels. Spawning is energetically costly, particularly for female fish that need to develop eggs. As a result, diploid walleye need to eat more food to grow and successfully spawn every year when compared to triploid walleye. Since most (>95%) of the mercury present in predatory fish comes from their prey, eating less food to grow the same amount means triploid fish are exposed to less mercury, and have lower mercury concentrations. Associated Publications: Farrell, C.J., B.M Johnson, A.G. Hansen, and C.A. Myrick. In press. Induced triploidy reduces mercury bioaccumulation in a piscivorous fish. Canadian Journal of Fisheries and Aquatic Sciences. Using gill nets to capture and test triploid and diploid walleye in Narraguinnep Reservoir for mercury levels. Sequence of images depicting the process of collecting, fertilizing, treating and hatching triploid walleye eggs for stocking into key Colorado reservoirs. COLORADO PARKS & WILDLIFE • 317 W. Prospect Rd., Fort Collins, CO 80526 • (970) 472-4432 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/f5164b387abd543f95acf90bef850d4b.pdf bb4dac1ad997dd48461cb549cff313f4 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Native Cutthroat Trout SEPTEMBER 2018 Rediscovery of the San Juan River basin’s native trout © GRANT WILCOX/CPW Nine years ago, the Greenback Cutthroat Trout Recovery Team commissioned a collaborative study by researchers from the University of Colorado, along with state, and federal biologists to examine Cutthroat Trout specimens collected in the late 1800s and housed in our nations most prestigious museums. The goal of that study was to establish what the native range of these fish was prior to European settlement. While these trout look similar to each other in outward appearance, inspection of their DNA revealed that six discrete lineages historically called Colorado home – essentially one in each major drainage basin. Four lineages are still found on the landscape today: two that comprise Colorado River Cutthroat Trout west of the Continental Divide, Greenback Cutthroat Trout in the South Platte River drainage, and Rio Grande Cutthroat Trout in their namesake river basin. The authors ©KEVIN ROGERS/CPW Distinct lineages of Cutthroat Trout evolved in six major drainage basins in Colorado Specimen collected from the San Juan River by C. E. Aiken in 1874 (now at the National Museum of Natural History in Washington D. C.) reported that the remaining two lineages were thought to be extinct: the Yellowfin Cutthroat Trout historically found in the headwaters of the Arkansas River, and one native to the San Juan River that was only known from two specimens collected near Pagosa Springs during the Wheeler Survey in 1874 while mapping the territories in what is now the American southwest. After learning that a previously unknown lineage of Cutthroat Trout was native to the San Juan basin, we launched an intensive search to determine if any relict populations remained tucked away in the corners of the rugged San Juan Mountains of southwest Colorado. COLORADO PARKS & WILDLIFE • 317 W. Prospect Rd., Fort Collins, CO 80526 • (970) 472-4432 • cpw.state.co.us �Approach ©KEVIN ROGERS/CPW Armed with new genetic markers with which to identify this San Juan lineage trout, we gathered tissue samples (fin clips) from all known cutthroat trout populations in southwest Colorado. We isolated DNA and sequenced a specific mitochondrial gene to identify any candidate fish that might have the same marker as those found in the museum specimens. We then examined their nuclear DNA to determine if any Present day San Juan lineage trout from a small stream in the hybridization had occurred with headwaters of the San Juan River Rainbow Trout or other subspecies of Cutthroat Trout, or if they appeared to be pure. Results • • • Surveyed the 20 waters thought to contain pure Cutthroat Trout in the San Juan River basin Eight of those waters harbored populations containing the same mitochondrial DNA marker found in the two museum specimens collected in 1874 Examination of nuclear DNA also suggests they are a unique lineage No evidence of hybridization with Rainbow Trout or other nonnative Cutthroat Trout lineages was detected Colorado River (Blue) Cu9hroat Trout • South Pla9e San Juan Colorado River (Green) Rio Grande Rainbow Trout DNA tree comparing relatedness of Colorado’s native Cutthroat Trout lineages (from map figure) to each other and Rainbow Trout. Longer branches represent more distant relationships Management implications This represents an exciting conservation success story, and is testimony to the effectiveness of our recovery strategies for preserving native trout diversity. Though genetic tools to distinguish these fish were not available until recently, biologists recognized that hidden diversity was likely still out there, and protected populations accordingly. Our conservation efforts will now focus on replicating these populations and securing them from invasion by nonnative trout so that future generations can enjoy this rare piece of Colorado’s legacy. � https://cpw.cvlcollections.org/files/original/acc7591147ec08f6417028a37c0eadf4.pdf 238626ae2f2d421b59033e28c42437d1 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Predation on Stocked Fish ASSESSING THE PREDATORY THREAT OF INTRODUCED SPECIES TO MANAGED SPORT FISH Does predation limit the survival of sport fish stocked into Colorado’s lakes and reservoirs? All fish are vulnerable to predation by larger fish during some phase of life. If predation is high and persistent, stocked fish may not survive long enough to grow to a size that can be caught and harvested in the numbers desired by anglers. In these situations, management actions such as stocking larger fish or adjusting harvest regulations on predators could boost survival. Determining whether different species pose a significant predatory threat to stocked sport fish, and if so, how to best manage the situation, first requires an examination of the interactions among suspected predators and stocked fish. Recent study: threat of yellow perch to stocked kokanee salmon fry Yellow perch were first detected by CPW in Blue Mesa Reservoir, Colorado’s premier kokanee salmon fishery, in 2001. Yellow perch feed on Daphnia (food for kokanee), other invertebrates, but also small fish. There was growing concern and perception from the public and some angler groups that yellow perch were having a detrimental effect on the stocked kokanee fry that maintain this phenomenal fishery. CPW determined that it was important to address these concerns objectively by conducting a focused study on the subject. During 2016, researchers estimated the seasonal diet and habitat use of yellow perch and compared these to brown trout and to the habitat use and growth of kokanee fry. Brown trout have been present since the reservoir was filled in 1965 so they were a good reference species for gauging the predatory threat of yellow perch. Key results and management implications: Contrary to perceptions, yellow perch showed a limited predatory threat to kokanee fry. Yellow perch behaved similarly to brown trout by occupying nearshore areas away from offshore kokanee and eating mostly crayfish and insects throughout the year. Predation by yellow perch and brown trout on kokanee was brief and confined to the inlet during spring when fry stocked upstream entered the reservoir. The pie charts below show how quickly kokanee fry disappeared from the diet of each predator. Kokanee were 50% of stomach contents for each species the morning fry entered the reservoir, but dropped to 0% one week later. Because brown trout were more abundant and consumed more individual fry, their predation on kokanee in the inlet was 39-times greater than yellow perch. Kokanee fry outgrew 58% of adult yellow perch by June and 95% by October, further limiting predation. Yellow perch did not measurably affect the amount of Daphnia available to kokanee. This research highlights the importance of addressing uncertainties with appropriately designed studies relevant to the species and reservoir in question to guide informed management decisions. Peer-reviewed publication: Hansen, A.G., J.S. Thompson, L.N. Hargis, D. Brauch, and B.M. Johnson. Under review. Predatory threat of illegally introduced yellow perch in a salmonid dominated reservoir food web. North American Journal of Fisheries Management. COLORADO PARKS & WILDLIFE • 317 W. Prospect Rd., Fort Collins, CO 80526 • (970) 472-4432 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/0e503984062372a68f45ba344dab22ac.pdf 9f12b640fab40b7dbcd287436fe12fe7 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Rainbow Trout Stocking Evaluations INCREASING POST-STOCKING SURVIVAL OF WHIRLING DISEASE RESISTANT RAINBOW TROUT Whirling Disease Resistant Rainbow Trout Whirling disease resistant Rainbow Trout have been stocked by CPW hatcheries over the past decade to reestablish Rainbow Trout populations in waters where populations experienced significant declines due to the establishment of whirling disease in the early 1990s. The German Rainbow (GR), or Hofer, a resistant but domesticated Rainbow Trout strain, has been crossed with other Rainbow Trout strains to maintain both whirling disease resistance and wild survival characteristics. Crosses of the GR with other wild strains, such as the Colorado River Rainbow and Harrison Lake Rainbow Trout, are used for stocking various locations, for instance in rivers versus lakes, dependent upon life history characteristics of the wild strain and the management objectives for each body of water. Since these crosses are a relatively new addition to Colorado’s stocking program, the effects of fish size at stocking and variety were evaluated to determine which stocking methods result in increased post-stocking survival and recruitment in newly-established whirling disease resistant Rainbow Trout populations. Rainbow Trout Stocking Evaluations in the upper Colorado River Subcatchable Stocking Evaluations A stocking strategy that was adopted in the years after whirling disease became established in Colorado, prior to the advent of resistant strains, was the use of large (> 6 inches) subcatchable fish. This was done because larger fish were less susceptible to whirling disease infection and predation. Whirling disease resistant Rainbow Trout, a cross between the GR and the Colorado River Rainbow Trout strains (H×C), were first stocked into the upper Colorado River below Windy Gap Reservoir in 2006, with additional stocking events in 2009 and 2010. These resistantStocking Floy-tagged H×C in Colorado River strain stocking events were also conducted with large subcatchable fish, similar to previous stocking events with susceptible strains. Prior to being stocked, all fish were individually tagged using external Floy tags to identify individuals upon recapture during annual population estimates. Although some natural reproduction took place in the upper Colorado River during this time, wild fry numbers remained low and little recruitment to the adult population occurred. As a result of both the low post-stocking survival of the stocked subcatchable fish and the low numbers of fry produced by these fish, the adult Rainbow Trout population continued to decline from 91 fish per mile in 2008 to 6 fish per mile in 2011 (Figure A; Fetherman et al. 2014). RBT per mile 200 200 (A) 100 100 0 0 2008 2009 2010 2011 Figure (A) Decline in the adult rainbow trout population following subcatchable stocking and (B) increase in the adult rainbow trout population following fry stocking in the upper Colorado River. (B) 2013 2014 2015 2016 2017 COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us �Fry Stocking Evaluations Because of the continued decline in the adult Rainbow Trout population following stocking of subcatchables, fry stocking was proposed as a possible alternative to increase recruitment to the adult population. Subcatchables are often held in the hatchery for six months or more to get the fish to larger sizes for stocking, whereas fry are stocked 1.5 months after hatching, reducing the amount of time spent in the hatchery and the potential influence of the hatchery environment on post-stocking survival. Use of larger subcatchables was no longer necessary due to the inherent resistance of the new strains. H×C were first stocked as fry in the upper Colorado River in 2013, with H×C fry continuing to be stocked annually through 2016. Fry were distributed by raft in appropriate fry habitat throughout the upper Colorado River. Electrofishing estimates conducted throughout the study section showed that the H×C fry persisted as well as naturally-produced brown trout fry in the same reaches. Additionally, the number of adult Rainbow Trout per mile increased each year following the commencement of fry stocking (Figure B), suggesting that the H×C fry were recruiting to the adult population. As such, stocking H×C fry versus subcatchables appeared to be the best stocking strategy for the Colorado River, and similar rivers across the state. Stocking H×C fry in the Colorado River German Rainbow (GR) versus H×C Fry Stocking Electrofishing for stocked rainbow trout fry The observed survival of the H×C fry was promising. However, studies had shown that eventual dilution of resistance of these stocks could be a concern (Fetherman et al. 2012). Reduced resistance in future generations would be much less likely when stocking pure GR fish. Therefore, stocking pure GR as fry could be an option for establishing whirling disease resistant Rainbow Trout populations in certain situations. Comparative Survival of GR and H×C Fry In a recent collaborative study with Colorado State University, a laboratory and field experiment were undertaken to compare the post-stocking survival of GR and H×C fry. The field experiment was conducted in one mile reaches of nine Colorado streams, selected for consistency in size and physical habitat characteristics. Each stream was stocked with 5,000 GR and 5,000 H×C fry, and survival was assessed at two months, six months, and one year post stocking. After one year in the streams, the strains survived equally well. In the laboratory experiment, equal numbers of GR and H×C were stocked into tanks with brown trout as predators and held for 24 hours. Again, survival did not differ between the strains. The results of this study indicated that stocking the GR as fry may be a viable option in some streams where whirling disease is enzootic (Avila et al. In review). To test this in a larger river system, GR fry were stocked in place of H×C fry in the Colorado River in 2016, and continue to be evaluated annually for survival and recruitment to the adult population. Fry stocking and recruitment evaluations will continue in the upper Colorado River through 2022. GR fry two months post-stocking References Avila, B. A., D. L. Winkelman, and E. R. Fetherman. In review. Survival of whirling disease resistant Rainbow Trout fry in the wild: a comparison of two strains. Journal of Aquatic Animal Health. Fetherman, E. R., D. L. Winkelman, G. J. Schisler, and M. F. Antolin. 2012 Genetic basis of differences in myxospore count between whirling disease-resistant and –susceptible strains of Rainbow Trout. Diseases of Aquatic Organisms 102:97-106. Fetherman, E. R., D. L. Winkelman, M. R. Baerwald, and G. J. Schisler. 2014. Survival and reproduction of Myxobolus cerebralis resistant Rainbow Trout in the Colorado River and increased survival of the age-0 progeny. PLoS ONE 9(5):e96954. COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/ffbee92f0a8622bd8cfa52adbe21f3b1.pdf 9513ab0f594e62bc580c0b9fd97bbb4f PDF Text Text REBUILDING FLOOD-DAMAGED DIVERSION STRUCTURES TO BENEFIT MULTIPLE USES Colorado Parks and Wildlife (CPW), the Colorado Water Conservation Board (CWCB), federal agencies and other stakeholders can assist municipalities, ditch and reservoir companies and other water users in reconstructing flood-damaged water diversion structures in a manner that will maintain historical water diversions while providing for fish and boat passage. CPW stream reconstruction specialists and engineers are available to share conceptual designs for structures successfully used throughout Colorado on all sizes of streams. These designs ensure that water users can fully divert under their decreed water rights while allowing fish access to the entire reach of stream, at little to no additional costs. Designs range from the traditional concrete diversion structure with associated rock ramps to stand-alone boulder cross-vanes, or a combination of concrete diversion structures and boulder cross-vanes. TRADITIONAL DIVERSION WITH ROCK RAMP BOULDER CROSS-VANE DIVERSION TRADITIONAL DIVERSION WITH ROCK RAMP BOULDER CROSS-VANE DIVERSION �Potential benefits of these types of diversion structures include: • • • • • • Allowing full diversion of decreed water rights while facilitating fish and boat passage Increasing habitat connectivity for fish Improving recreational potential and reducing hazards Withstanding high flows (boulder cross-vane diversions on Boulder and South Boulder Creek survived the recent flooding, minus a few boulders) Serving as a temporary diversion structure during this period of high construction costs, or while the owner pursues additional financial assistance Enhancing stream health without impacting ability to fully divert and use water If you are interested in exploring this approach to rebuilding, please contact: Ken Kehmeier, Colorado Parks and Wildlife 317 W. Prospect Ft. Collins, CO 80526 ken.kehmeier@state.co.us FUNDING SOURCES INCLUDE: CWCB Emergency Loans: Available to fund repair or replacement of raw water supply structures damaged by flood, including river diversion dams, ditch rehabilitation, and measuring devices; can incorporate design elements to facilitate fish passage. Terms: 3 years of no payment and zero interest + 27 yrs of payments at current CWCB interest rates. (Contact Anna Mauss at 303-866-3441, ext. 3224; anna.mauss@state.co.us). CWCB Fish and Wildlife Resources Fund: Grants to owners of existing water supply facilities to help balance between development of the state’s resources and protection of the state’s fish and wildlife resources. Can be used for construction projects designed to directly mitigate or significantly reduce the environmental impacts of existing water facilities. (Contact Chris Sturm at 303-866-3441, ext. 3236; chris.sturm@state.co.us). U.S. Department of Agriculture: A list of USDA funding sources is attached to this fact sheet. For information on CWCB’s loan and grant programs, see http://cwcb.state.co.us/LoansGrants/Pages/LoansGrantsHome.aspx OTHER RESOURCES: Trout Unlimited can provide seed money to help with fish-friendly rebuilding efforts; assist in seeking grants for restoration projects, and provide volunteer support on projects (eligible as match for FEMA). (Contact Stephanie Scott at sscott@tu.org). U.S. Fish and Wildlife Service can provide assistance in project design, hydrologic analysis and some funding towards improving or establishing “fish friendly” passage designs, irrigation diversions, road culverts and bridges and the removal of obsolete dams and instream structures. Projects must have a fish and wildlife tie and focus on state or federal protected species. Funding decisions are based on region-wide needs, USFWS priorities and needs identified by USFWS’s various aquatic resource partners. (Contact Scott Roth at scott_roth@fws.gov or Pam Sponholtz at Pamela_sponholtz@fws.gov). �U.S. Department of Agriculture Programs – Potential uses for Colorado Flood Recovery NRCS Program Emergency Watershed Protection Program (EWPP) Emergency Watershed Protection Flood Plain Easements (EWP-FPE) Environmental Quality Incentive Program (EQIP) Wildlife Habitat Incentive Program (WHIP) Wetland Reserve Program (WRP) Relevance to Flood Recovery Financial and technical assistance for sediment and debris removal, stream bank and channel stabilization, or dike/levee repairs. Some limited potential to assist with stream channel repairs associated with irrigation structures. Financial and technical assistance to purchase a permanent easement and restore the floodplain to natural conditions where it is a more economical and prudent approach to reducing a threat to life or property. Time Frame Predominantly short term. Financial and technical assistance for Repair replacement of on farm irrigation systems. Some limited potential for off farm irrigation systems. Potential for land reclamation of ag land damaged by overland flood flows. Potential use for bank stabilization, channel modification, and vegetation establishment to develop and improve wildlife habitat. Long Term. Competitive grant process. Potential use in flood plains to convert damaged property from agricultural use to permanent wetlands. Long term. Long Term. Competitive grant process Long Term. Competitive grant process requiring submittal of application for EQIP assistance through local NRCS office. Who Is Eligible Public and private landowners are eligible for assistance but must be represented by a project sponsor. Sponsors are a local unit of government. Private landowners within the floodplain. How To Apply The Sponsor applies for NRCS assistance via a letter to the NRCS State Conservationist within 60 days of the flood. Sponsor and NRCS work with affected land owners to identify and prioritize recovery funding needs. Agricultural landowners apply directly to NRCS local offices. A project sponsor is required for projects involving the conversion of residential or other developed land uses from the floodplain. The Sponsor is required to purchase the remaining property after structures are removed. For properties with residential or other land use requiring removal of structures the landowners work with a local EWP Sponsor to make an application to NRCS. Assistance provided to individuals for use on agricultural land. Individual submit an application for EQIP assistance through their local NRCS office. Assistance provided to individuals for use on agricultural and nonindustrial private forest land. Assistance provided to individuals for use on agricultural* land. Individual submit an application for WHIP assistance through their local NRCS office. What Is Provided EWPP provides varying amounts of technical assistance and 75% of cost for installing eligible recovery measures. Recovery measures may be temporary or permanent measures. Comments Project eligibility limits. Funding availability is subject to congressional appropriation. NRCS will pay up to 100% of the easement value and up to 100% of the costs for easement restoration. Project eligibility limits. Funding availability is subject to congressional appropriation. For residential housing, NRCS will pay up to 100% of the easement value and up to 100% of the structure's value if the landowner chooses to have it demolished or relocated. EQIP provides 100% of needed technical assistance and an incentive payment of typically 50%-75% of cost to construct required conservation practices. NRCS EWP-FP Program Contact: John Andrews. 720-544-2834 WHIP provides 100% of technical assistance and an incentive payment typically in range of 50%75% of cost to construct habitat improvement measures. NRCS purchases 30 year or perpetual easement and shares cost of constructing measures necessary to restore wetland functions. NRCS EWPP Program Contact: John Andrews 720-544-2834 Program availability for new contracts may be altered by pending legislation to reauthorize the Farm Bill. NRCS EQIP Program Contact: Dawn Jackson. 720-544-2805 Applications for new projects are on hold pending legislation to reauthorize the Farm Bill. WHIP fund availability is aligned to National & State priorities. Preble’s Mouse habitat is a priority issue in the flooded areas. NRCS WHIP Program Contact: Dawn Jackson. 720-544-2805 Program availability for new contracts may be subject to pending legislation. NRCS WRP Program Contact: Dawn Jackson. 720-544-2805 �FSA Program Emergency Conservation Program (ECP) Relevance to Flood Recovery Time Frame Financial assistance for debris removal, Predominantly short term. fence restoration, grading, shaping and releveling ag land, and restoring conservation structures. Who Is Eligible Assistance provided to individuals for use on agricultural lands. How To Apply Individuals submit an application for assistance through their local FSA Office. What Is Provided ECP provides financial assistance up to 75% of cost for installing eligible recovery measures, or up to 90% for Limited Resource producers. Emergency Loan Program Provides emergency loans to help producers recover from production and physical losses due to drought, flooding, other natural disasters or quarantine. Owners or operators of land located in a county declared by the President or designated by the Secretary of Agriculture as a primary disaster area or quarantine area who suffered at least a 30% loss. Individuals submit a loan application through their local FSA Office. Producers can borrow up to 100% of actual production or physical losses, to a maximum amount of $500,000. Interest rates vary with a loan term of one to twenty years. Must apply within 8 months of the county’s disaster or quarantine designation. Comments FSA ECP Program Contact: Jenny Peterson 720-544-2895 FSA Emergency Loan Program Contact: Gary Wall 720-5442892 � https://cpw.cvlcollections.org/files/original/7014bb786a6cd324b733b3b45939f554.pdf 298c51e4bfdd0b887b75e5457680c3ad PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Renibacterium salmoninarum Transmission Research TRANSMISSION OF RENIBACTERIUM SALMONINARUM (BACTERIAL KIDNEY DISEASE) IN HATCHERY-REARED FISH Prevalence of Renibacterium salmoninarum in the US. Highest detections occur in the Pacific Northwest and Midwest. Renibacterium salmoninarum, the bacterium that causes bacterial kidney disease (BKD), was first described in Scotland in 1930, and first detected in the US in 1934. BKD is now found in trout and salmon throughout the US and worldwide, and can cause significant mortality in infected populations. In the US, the bacterium is most commonly detected in Coho and Chinook Salmon in the Pacific Northwest, and Brook Trout and Brown Trout in the Midwest. The transfer of infected eggs and the practice of pasteurizing fish by-products for fish feed (now discontinued) are suspected to have contributed to the worldwide spread of the pathogen. R. salmoninarum can be transmitted in two ways, presenting challenges for prevention and management. Horizontal transmission of the bacteria is not completely understood. However, fish may become infected through direct contact with another infected fish, ingestion of contaminated fecal matter, or contact with a contaminated water source from which the bacteria enters through the gills, eyes, gut, and external injuries of the fish. Vertical transmission occurs during the spawn. Bacteria in the female find their way into the eggs during egg development. There is no method for safely disinfecting the inside of the eggs, and using iodine to disinfect the egg surface during hatchery spawns is not effective for preventing vertical transmission. Horizontal and vertical transmission of R. salmoninarum. R. salmoninarum is a regulated pathogen in Colorado. Current regulations prevent the transfer or stocking of infected fish. While infrequently found in Colorado since the 1960’s, it has recently been detected in six state and federal hatcheries. In 2015, R. salmoninarum was detected in the CPW Glenwood Springs Hatchery. To eradicate the pathogen and prevent stocking infected fish, the hatchery was temporarily depopulated. R. salmoninarum was also detected in other CPW hatcheries rearing valuable brood stocks of whirling disease-resistant Rainbow Trout and Native Greenback Cutthroat Trout, and depopulation of these hatcheries was not an option. Recent management options have focused on methods to prevent vertical transmission during fish spawning, although other approaches are also being examined. Management Options for Controlling Bacteria Transmission Lethal spawning has been evaluated in Rainbow Trout and Cutthroat Trout brood stocks at the CPW Poudre Rearing Unit (PRU) and Fish Research Hatchery (FRH). Eggs are fertilized and collected as normal from brood fish during the spawn. After being spawned, adult fish are euthanized and tested for R. salmoninarum. Eggs from positive parents are then culled so that only eggs from negative parents are retained on the unit for stocking and management purposes. This technique has shown promise in preventing vertical transmission. However, more research was needed to understand the transmission rates of R. salmoninarum, develop management and regulatory protocols to decrease the prevalence of the pathogen within hatchery brood stocks, and limit the dissemination of positive progeny to other waters and hatcheries in Colorado. COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us �Treatment Adults Progeny Antibiotics administered orally or by injection have been shown to reduce bacterial Control 10 Tanks 67 Families concentrations in fish. Erythromycin (Erymin 79 Families 334 Fish 200), an antibiotic approved for use in fish, 3 Tanks was injected into Rainbow Trout at the CPW 12 Families FRH to determine if its use could reduce R. Erymin 200 12 Tanks salmoninarum levels in spawning fish and control vertical transmission to progeny. Male 64 Families 0 Tanks 200 Fish and female brood fish were injected with the 64 Families antibiotic three times prior to spawning. The 25 Tanks injections reduced bacteria levels in the Key injected fish to below detectable levels. 0 Families 2 Tanks However, progeny that tested positive for R. Negative Positive salmoninarum were produced by both treated and control fish that had tested negative for the bacteria. Additionally, positive control adults produced negative progeny. Results also indicated that the male may play a role in vertical transmission in inland trout, a significant finding as only females were previously known to contribute to vertical transmission of the bacteria. This study revealed several unknowns regarding pathogen transmission that needed to be answered for effective management in Cutthroat Trout. CPW and Colorado State University are currently conducting two studies to better understand transmission rates in Native Greenback Cutthroat Trout. Transmission Studies in Native Greenback Cutthroat Trout Horizontal Transmission Horizontal transmission of R. salmoninarum within a hatchery may pose a risk to fish throughout the unit, as well as feral fish in the river below a unit if the bacteria are present in the hatchery effluent. In summer 2019, two sentinel cages were deployed in six locations at PRU and at three time periods encompassing a range of optimal temperatures for bacterial growth (10-18°C). Each cage housed 10 Cutthroat Trout. After 30 days, fish were collected and tested for R. salmoninarum. Only one fish out of a total of 360 tested positive. The cage containing the positive fish had been deployed near highly-positive Rainbow Trout. These results suggest the rate of horizontal transmission to fish both on, and in the river below a positive unit may be insignificant, even when conditions are optimal for the bacteria to persist. Vertical Transmission Eggs from unique male-female pairs of Cutthroat Trout were collected during the spawn at PRU in May 2019. Adult fish were tested for R. salmoninarum after being spawned to determine the potential infection status of the progeny created from these spawns. Thirty-two tanks of progeny are being reared at the FRH: one containing progeny from a male negative × female negative pair, six from a male positive × female negative pair, four from a male negative × female positive pair, and 21 from a Progeny collected from positive adults male positive × female positive pair. Progeny from each tank will be tested for R. salmoninarum and associated antibodies, indicating that the progeny had mounted an immune response to the bacteria at some point prior to the testing, at six months and one year of age. The results will be used to understand vertical transmission rates, male and female contributions to vertical transmission, and the bacterial load at which transmission occurs from parent to offspring. Overall, the results from the transmission studies will be used to inform future management options. Results from these transmission studies will be available in 2021. Associated Literature Fetherman, E. R., G. J. Schisler, and B. W. Avila. 2018. Sport Fish Research Studies. Federal Aid Project F-394-R18. Federal Aid in Fish and Wildlife Restoration, Job Progress Report. Colorado Parks and Wildlife, Aquatic Wildlife Research Section. Fort Collins, Colorado. Fetherman, E. R., B. Neuschwanger, T. Davis, C. L. Wells, and A. Kraft. In review. Use of Erymin 200 injections for reducing vertical transmission of Renibacterium salmoninarum in a Rainbow Trout brood stock. Diseases of Aquatic Organisms. COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/6be1c6ecbb80ea396a819a49b0f2e804.pdf 878f70cdb2a145b5b27a160feefac477 PDF Text Text The "Three Species" Background H istorically, the bluehead sucker, the flannelmouth sucker and the roundtail chub - the so-called three species inhabited much of the upper Colorado River Basin below 8,500 feet in western Colorado. Today, the three species occupy only 50 percent of their native range in the state. Colorado wildlife managers are concerned about the range contraction and the invasion of non-native suckers, which hybridize with the native suckers. Dam construction that obstructed fish movement, increased water diversions and reservoirs replacing free flowing streams as habitat may have influenced the range contraction. The remaining free-flowing water habitat below reservoirs has also changed - colder temperatures, less fluctuation in water levels and reduced sediment. Four related native fish - the bonytail chub, the razorback sucker, the humpback chub and the Colorado pikeminnow - experienced greater range reductions and are federally listed endangered species. Colorado wildlife researchers want to prevent additional federal Listings. Three Species Research Objectives To prevent a federal endangered species listing for these three native fish species and the resulting restrictions on state management options, Colorado Parks and Wildlife (CPW) will create a conservation plan to protect and enhance the remaining populations. Under that plan, CPW could expand and repatriate tJ1e three species, using hatchery produced offspring from captive broodstock. CPW has several research projects underway. CurrentThree Species Research Projects Field work to address the various objectives was initiated in 2012. Scores of randomly chosen sites witJ1in tJ1e historic range have been visited in 2012 and 2013 lo determine whether three species fishes are present. H undreds of genetic tissue samples an d hundreds of fin ray bones have been collected and are undergoing analysis. O ngoing research projects include: Bluehead sucker Determine current distribution of the three species in comparison to historic distribution. Assess genetic purity and diversity in sucker populations and make recommendations for numbers and sources of native sucker broodstocks housed at CPW's Native Aquatic Species Restoration Facility (NASRF) in Alamosa. Evaluate the extent of sucker hybridization occurring in several major drainages and assess differing outcomes compared to drainages experiencing lesser rates of hybridization. Flannelmouth sucker Evaluate spawning locations in tributaries, fidelity to spawning locations, and rearing habitats in the White River basin above Kenney Reservoir (a relatively intact native fish community), in collaboration with Colorado State University (CSU). Exanline population age structure and growth patterns using thin-sectioned fin ray bones to determine flow and temperature conditions leading lo successful spawning an d recruitment of native suckers in flow-impaired streams compared to streams with better flows. Roundtail chub Help develop field keys for sucker and hybrid sucker identification. Collaborators in the present research include Colorado State University, University of Wyoming, and Colorado Parks and Wildlife. COLORADO PARKS & WILDLIFE • 6060 Broadway, Denver, CO 80216 • (303) 297-1192 • cpw.state.co.us �Highlights of Recent Three Species Research and Management Bluehead sucker genetic analyses suggest that there is considerable genetic exchange among populations, leading to the acquisition of two broodstocks representing CPW's Northwest and Southwest Regions. Flannel.mouth sucker genetic analyses also revealed populations that exchange genetic material and tl1at exhibit considerable genetic diversity at the individual population level. One broodstock from tl1e Northwest Region has been acquired. Another will likely be obtained for tl1e Soutl1west Region in tl1e future. Additional genetic analyses are underway using a second method to confirm the results of prior research. Roundtail chub broodstocks have been held at CPW's NASRF facility for a number of years preceding the current research effort. Offspring from tl1e broodstocks are stocked in soutl1western Colorado and on tl1e Jicarilla Apache Indian Reservation in New Mexico. Cutting fin ray bone All of the three species are considered to be relatively longlived, witl1 specimens exceeding 20 years of age known for each species. Large, mature flrumelrnouth suckers tagged using passive integrated transponders (PIT) in the Colorado River in 2003 have been detected eight to ten years later as tl1ey passed over stationary PIT tag antenna between 2011 and 20 13. Fin rays are known to be suitable structures for aging these longlived fish, comparable to using otolitl1s - the bone from the inner ear - which require lethal srunpling. Models to predict native sucker biomass from two-dimensional strerun hydraulic modeling were developed for western Colorado rivers in the 2000s. In the srune study, bluehead sucker abundance was found to be a reliable indicator ofbaseflows adequate to sustain the entire native fish assemblage. Sample points in northwest Colorado tn Magnified fin ray bone section Sample points in southwest Colorado 1M COLORADO PARKS & WILDLIFE • 6060 Broadway, Denver, CO 80216 • (303) 297-1192 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/652756f4d711a35e8bf1ed49fbe6712a.pdf a0559d0c4804f24d9ff379084192cb1d PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Tiger Trout Research TRANSFORMING UNDESIRABLE FISH INTO QUALITY FISHING OPPORTUNITIES FOR ANGLERS What are tiger trout and how can Colorado’s lakes benefit? Many of Colorado’s coldwater lakes contain fish species, such as suckers and minnows, which provide little value to anglers, compete with managed sport fish, and have the potential to reduce water quality. However, these undesirable fish may be valuable prey items. Sterile fish that have the ability to grow to predatory size quickly and eat the unwanted fish could act as a biological control agent and provide a unique fishing opportunity. Being unable to reproduce, sterile fish can be closely managed through stocking and harvest regulations. Tiger trout, a sterile hybrid between male brook trout and female brown trout, have the potential to fill this role. Tiger trout have already been stocked in some Colorado lakes. Our understanding of what tiger trout eat and how well they grow and survive in lakes with different species of undesirable fish remains limited, and should be fully investigated as a management tool. Fine-mesh net full of fathead minnows. Flushing the stomach of a young tiger trout to evaluate diet (this fish was eating insect larvae). Three-year-old, 5 ½ lb tiger trout from a lake containing fathead minnows. Study objectives Factors such as number of tiger trout stocked per acre of lake and the presence of small-bodied minnows versus largerbodied suckers may affect the ability of tiger trout to grow quickly enough and survive long enough to eat and suppress the population of undesirable fish. The objective of this research is to quantify the feeding, growth and survival of tiger trout stocked into lakes with different species of undesirable fish. Results will help CPW prioritize which lakes receive tiger trout, inform appropriate numbers to stock, and calibrate expectations on the effectiveness of tiger trout as a biological control agent. Informed stocking translates into (1) efficient use of the limited number of tiger trout produced by our hatchery system, (2) a greater chance tiger trout will perform well at the onset of stocking, and (3) more rapid development of a quality fishing opportunity for anglers. Early results Preliminary observations suggest that tiger trout grow well and can suppress populations of undesirable fish in lakes containing small-bodied minnows. For example, based on catch rates in nets (number of fish captured per hour of soak time), fathead minnows were much more numerous in three lakes where tiger trout were either absent or only present for one year (blue bar in figure to right) compared with two lakes where tiger trout were present for 2-3 years (red bar). In addition, tiger trout grew from an average of 4.0 inches at time of stocking to 19.2 inches after just 3 years in one of the lakes. Continued study and monitoring is needed to validate this apparent strong influence of tiger trout. COLORADO PARKS & WILDLIFE • 317 W. Prospect Rd., Fort Collins, CO 80526 • (970) 472-4432 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/ba6815cdabc369ce60019b13994d7615.pdf ec3be8a63caf95b53865248862ebfd3e PDF Text Text What is Toe Wood? “Toe wood” is a term that describes the use of large woody materials such as log stems, root wads and limbs for stabilizing stream banks and enhancing fish habitat (Figure A). The “toe” is the region at the base of the bank most prone to erosion where it transitions from a vertical to horizontal plane. Using large wood to restore streams is not a new concept. Toe wood evolved from the use of root wads to stabilize streambanks and was originally called “root rap,” derived from the term “riprap,” with the earliest applications from the 1960s (Rosgen 2019). Toe wood is useful for temporarily stabilizing banks until riparian vegetation becomes established, creating a “living,” vegetated streambank for long-term stability. CPW research has documented the direct benefits of toe wood functioning as fish habitat by improving habitat complexity, increasing fish population abundance and biomass, and enhancing pool depths. Specifically, toe wood-treated pools were deeper (Figure B; average difference = 1.5 ft), held more quality (>14“) adult Brown Trout (× 19), higher Rainbow Trout biomass (Figure C; × 8.1), and higher total Brown Trout abundance (× 2) than pools without large wood. In addition, total fish population abundance (× 1.5) and biomass (Figure D) were highest in toe wood pools (Kondratieff and Richer 2022). Our research has demonstrated the effectiveness of toe wood as a bank stabilizing technique and for riparian vegetation establishment, providing increased shading, overhead cover, and terrestrial insect habitat, thereby indirectly benefitting fish populations (Figure E). (A) (B) (C) (D) �Why Toe Wood? Human activities have led to an overall reduction in the amount, size, and sources of wood found in natural channels. Many studies have demonstrated the value of large wood for fish habitat in streams. Wood deposited on outside channel bends or within pools can induce scour, enhancing pool depths in streams. In contrast, wood deposited in the middle of stream channels in riffles or glides can induce deposition leading to island formation and development of complex side channels. Wood deposited on floodplains creates roughness that traps and promotes deposition of rich, nutrient-laden fine soils that benefit riparian plant species. Toe wood can be used to improve physical habitat conditions and increase carrying capacity for fish if it addresses limiting factors such as a lack of low flow refugia (i.e., deep pools), undercut banks, or habitat complexity. A major benefit of using toe wood as an alternative to other toe-stabilizing techniques like rock or boulder materials is that wood is a natural, biodegradable material. Over time, wood decomposes providing food, nutrients, carbon inputs, and other ecological benefits back to the stream and riparian ecosystem that boulders, rock, or concrete riprap materials do not provide. Toe wood installations can be done using completely natural and native materials without the use of steel bolts, cables, anchors, or large ballast boulders. This serves as an economic advantage of toe wood for use in trout streams found within the Rocky Mountain region as sources of woody materials are readily available in close in proximity to project sites, reducing processing, transporting, and hauling costs. Limitations Toe wood is not recommended for use in every river setting in the same way that naturally occurring large wood is not found in every stream. Some places where toe wood is not recommended include deep canyons or other places where floodplains are non-existent, including highly-confined river channels. Toe wood should not be installed immediately upstream of bridges, culverts, and other locations where dislodged wood pieces can hang up on structures downstream causing blockages or obstructing river flows. River locations where there are multiple user groups such as kayakers and rafters might not be good candidates for installing toe wood for human safely reasons since wood in streams can form dangerous hydraulic conditions that can increase drowning risk. Other design considerations that might limit the use of toe wood in certain river settings include consideration of the buoyancy, quality, and type of wood materials available. Toe wood installed in locations that are subject to high levels of angler or cattle foot traffic should include fencing or other exclusionary devices to limit disturbance to erosion-prone outside banks and protect riparian plantings. (E) Kondratieff, M. C., and E. E. Richer. 2022. Stream Habitat Investigations and Assistance Annual Report. Colorado Parks and Wildlife, Aquatic Wildlife Research Section. Fort Collins, Colorado. Rosgen, D. 2019. Natural channel design for river restoration. In P. Maurice (Ed.), Encyclopedia of water: science, technology, and society, pp. 11431155. Hoboken, New Jersey: John Wiley & Sons, Inc. DOIhttps://doi.org/10.1002/9781119300762.wsts0100 � https://cpw.cvlcollections.org/files/original/74c4ead606dbdae253e157badf93cf16.pdf 9c4277d3c8f165f48c9bc3203c87fabc PDF Text Text   �    � https://cpw.cvlcollections.org/files/original/bd9a3036655f4c4532d5092a9fcc3326.pdf f266b9b4625d8e39271ae74d0b26c3ef PDF Text Text , C O L O R A D O P A R K S & W I L D L I F E Whirling Disease Research September 2013 Whirling Disease Research Objectives Colorado Parks and Wildlife (CPW) has made whirling disease research a high priority for more than 20 years as part of the agency’s mission to conserve and perpetuate wildlife resources. When whirling disease first appeared in the state in the 1980s, CPW researchers started exhaustive projects to control the spread of whirling disease, limit the damage to fisheries and develop other solutions. The CPW work also includes cooperative investigations with researchers in other states to coordinate resources. Whirling Disease Background Whirling disease is caused by a microscopic parasite that infects trout and salmon, resulting in severe deformities and death in young fish. The disease gets its name from the abnormal whirling or erratic tail chasing movements of some infected fish. Symptoms also may include a black tail in young fish and a deformed skull or spinal column in adult fish. There is no known cure for fish infected with the parasite. Impacts of Whirling Disease in Colorado A shipment of trout from a private, out-of-state hatchery accidently brought the parasite to Colorado in the 1980s. By the mid-1990s, whirling disease had spread throughout most of the state’s major river drainages. Whirling disease has impacted rainbow, brook and cutthroat trout populations throughout Colorado, and is known to occur in high mountain lakes above 12,000 feet. The parasite also infected most of the state’s coldwater hatcheries, reducing production and fishing opportunities for anglers. Whirling disease doesn’t infect humans and eating an infected fish isn’t harmful. CPW Whirling Disease Studies The cooperative investigations initiated by CPW have led to the development of several effective control strategies in CPW hatcheries, which stopped the spread of whirling disease through stocking operations. Research continues into protecting uninfected waterways and providing excellent fishing opportunities. These current CPW research projects have shown a great deal of promise: Trout Studies CPW researchers developed rainbow trout strains that are resistant to whirling disease and are evaluating their uses in stocking operations. These strains of fish are able to survive exposure to the parasite. Some of these strains are now produced in CPW hatcheries for stocking. Current evaluations are focused on determining which varieties have the best growth, survival and value for anglers. There is ongoing work to optimize the production of these rainbow trout strains in our state hatcheries. Other disease resistant varieties of rainbow trout are being tested for their ability to reproduce and survive in the wild to re-establish and maintain natural self-sustaining populations. Several locations that were stocked with resistant strains already show evidence of natural reproduction and survival in rivers, including the Gunnison, Arkansas and Colorado. Additional sites are being stocked in coordination with further research and management activities. COLORADO PARKS & WILDLIFE • 6060 Broadway, Denver, CO 80216 • (303) 297-1192 • cpw.state.co.us �Resistant Worm Studies The complex life cycle of whirling disease poses challenges to controlling the spread. The parasite, Myxobolus cerebralis, starts life as a water-borne spore on the bottom of waterways. Small worms, Tubifex tubifex, eat the parasite spores and become infected. The parasite multiplies within the worms. the offspring are released into the water in a microscopic free-floating stage that attaches to fish, infecting them. Recent findings: • Various lineages of worms have differences in susceptibility to whirling disease. Some of these worms are able to eat the whirling disease parasite without becoming infected. Transplanting resistant strains of worms to areas where the susceptible varieties exist may help reduce the level of infection in those areas. • Studies in the Upper Colorado River Basin and Windy Gap Reservoir dating back to 1997 found four lineages of T. tubifex, including three with lesser or no susceptibility to the disease. Ongoing research found that those three lineages have become the dominant varieties in the reservoir while the most susceptible worm lineage has declined to less than 15 percent of the population. There’s no known cause for the shift, but CPW researchers are continuing their work. Whirling Disease Life Cycle Myxobolus cerebralis Young rainbow trout Infected adult brown trout Ongoing Prevention Strategies CPW researchers worked with wildlife managers and other agencies to develop prevention strategies that are used successfully throughout Colorado to control the spread of whirling disease into additional waterways: • Protocols to keep hatcheries disease free, including periodic testing and installation of ultraviolet lights at one hatchery to kill whirling disease spores. • Policies to protect uninfected streams and rivers from receiving stocking fish from infected hatcheries. Whirling Disease In Colorado COLORADO PARKS & WILDLIFE • 6060 Broadway, Denver, CO 80216 • (303) 297-1192 • cpw.state.co.us � https://cpw.cvlcollections.org/files/original/c457d2fb759dabeb095f1d9f20360c56.pdf 67164fc05558da189b53c504957f1560 PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Whitewater Park Studies RESEARCH RESULTS AND DESIGN GUIDELINES Whitewater Park Research With over 30 whitewater parks (WWPs) either completed or in the planning phases, Colorado is the epicenter for WWP development in the United States. Although WWPs provide economic and recreational benefits for local communities (Hagenstad et al. 2000; Loomis and McTernan 2011), they may have unintended impacts on instream biota and stream functions, particularly when the hydraulic conditions formed by the WWP are different from those naturally found in the surrounding river. The impact of WWPs on habitat connectivity and instream habitat quality have been the focus of several recent studies. Although these studies have primarily focused on fish passage and habitat, impacts to aquatic insects and sediment transport may also occur at WWPs. Fish Passage Impacts The elements that create a desirable surf wave (increased velocity, decreased depth, a hydraulic jump, and a stable, often grouted stream channel) create conditions that can impede fish movement. Swimming speeds and jumping ability vary greatly between fish species. Suppression of upstream trout movement has been documented at WWP structures, but the degree of impact varied by fish size and characteristics of the individual structure (Stephens et al. 2015; Fox et al. 2016). As trout are among the strongest swimming and jumping fish species in Colorado, small-bodied and weaker-swimming fish native to Colorado streams are even more susceptible to habitat fragmentation associated with WWP development. Brown Trout Mottled Sculpin Fish Habitat Impacts Although WWPs create deep pools, observed fish densities were significantly higher in natural pools than in WWP pools (Kolden et al. 2015; Kondratieff et al. in preparation). Habitat degradation in WWPs was associated with the unnatural hydraulics created by the recreational features and conversion of riffle habitat to drops over the wave structures. Design Guidelines CPW recommends that adequate environmental safeguards be included in the design and construction of WWPs to ensure that stream functions, fisheries, and recreational fishing are not adversely impacted. Each structure must be examined on a case-by-case basis, and monitoring and adaptive management should be included in the proposed project budget. COLORADO PARKS & WILDLIFE • 1313 Sherman St., Denver, CO 80203 • (303) 297-1192 • cpw.state.co.us �Site Selection   Design and construction of WWPs should preserve the natural aesthetic qualities of the river. WWPs should be located in degraded reaches when possible and should aim to improve the natural functions of the reach rather than maintain degraded conditions. WWPs should not be constructed in natural, un-modified river channels (American Whitewater 2007). WWP sites should be selected to minimize recreational conflicts with anglers. There is increased potential for boaters to displace anglers at WWP sites, especially during the summer months. If WWP construction affects a popular fishing location, mitigation such as new fishing access or habitat improvements should be considered. Ecological Design Considerations       WWP structures must be designed to allow upstream fish passage for all life stages of native and sport fishes present throughout the annual hydrologic cycle. Fish passage is dependent on water velocity, water depth, vertical height of structures, linear distance of the passage corridor, surface roughness, and attraction flow. Hydraulic characteristics at WWP features generally conflict with ideal conditions for fish passage. Therefore, a fish passage channel separate from the WWP structure may be necessary. The passage channel should meet hydraulic design criteria for target species across a range of flows. Hydraulic modeling of the proposed structure should be conducted during the initial design phase to evaluate potential impacts to fish passage and habitat. Streambed and bank disturbance due to construction activities should be scheduled for a time of year when egg incubation is not occurring. An increase in fine sediment to the stream during incubation can suffocate developing embryos. Erosion control and revegetation plans utilizing native riparian species should be required for each project. WWP structures should not cause sediment deposition upstream or downstream of the structure. Sediment deposition can eliminate fish and benthic macroinvertebrate habitats, create favorable conditions for the spread of whirling disease in trout, and increase flooding risk if sediment deposition decreases channel capacity. Recreational In-channel Diversion (RICD) water rights can be acquired for WWPs to provide recreational experiences in and on the water. These protected flows should be managed to benefit boating recreation as well as conservation and management of native and sport fish. Flows deviating from the natural flow regime, such as water calls during spawning periods, could have adverse impacts on stream ecology (Poff et al. 1997). References American Whitewater, 2007. Whitewater Parks – Considerations and Case Studies. https://www.americanwhitewater.org/content/Wiki/stewardship:whitewater_parks Fox, B. D., B. P. Bledsoe, E. Kolden, M. C. Kondratieff, and C. A. Myrick. 2016. Ecohydraulic evaluation of whitewater parks as a fish passage barrier. Journal of the American Water Resources Association. DOI: 10.1111/1752-1688.12397. Hagenstad, M., J. Henderson, R. S. Raucher, J. Whitcomb. 2000. Preliminary evaluation of the beneficial value of waters diverted in the Clear Creek Whitewater Park in the City of Golden. Stratus Consulting. Kolden, E., B. D. Fox, B. P. Bledsoe, and M. C. Kondratieff. 2016. Modelling whitewater park hydraulics and fish habitat in Colorado. River Research and Applications. DOI: 10.1002/rra.2931. Kondratieff, M. C., K. Kinzli, and E. R. Fetherman. In preparation. Eco-hydraulic evaluation of whitewater parks as fish habitat in Colorado. Loomis, J., and J. McTernan. 2011. Fort Collins Whitewater Park economic assessment. Department of Agricultural and Resource Economics, Colorado State University. Poff, N. L., J. D. Allan, M. B. Bain, J. R. Karr, K. L. Prestegaard, B. D. Richter, R. E. Sparks, and J. C. Stromberg. 1997. The natural flow regime: a paradigm for river conservation and restoration. BioScience 47(11): 769-784. Stephens, T. A., B. P. Bledsoe, B. D. Fox, E. Kolden, and M. C. Kondratieff. 2016. Effects of whitewater parks on fish passage: a spatially explicit hydraulic analysis. Ecological Engineering 83: 305–318. � https://cpw.cvlcollections.org/files/original/c7b366871a2b0816c602da02642e6d4f.pdf 5d95d6da20aca9a41df6d679cae1ac2b PDF Text Text C O L O R A D O P A R K S & W I L D L I F E Windy Gap Fish Movement Study EVALUATING MOVEMENT IN THE COLORADO AND FRASER RIVERS PRIOR TO CONSTRUCTION OF THE CRCC Windy Gap Fish Movement Study Objectives The Windy Gap fish movement study is being conducted in Grand County in conjunction with the construction of the Colorado River Connectivity Channel (CRCC), which will reconnect the Colorado and Fraser rivers above Windy Gap Reservoir to the Colorado River below Windy Gap Reservoir for the first time since the early 1980s. Construction of the CRCC around Windy Gap Reservoir will allow fish movement and provide access to favorable habitats, such as optimal spawning locations, that have been previously unavailable to populations upstream and downstream of the reservoir. The primary objectives of the study are to evaluate fish movement patterns prior to the construction of the CRCC, and that the CRCC is being used for fish passage after construction. Evaluations are taking place on Northern Water, City of Granby, and private properties above and below Windy Gap Reservoir. To accomplish this, the fish movement study involves collaboration between these entities, as well as CPW aquatic researchers and biologists, Trout Unlimited, and Grand County Learning by Doing. Population Estimates and PIT Tagging Population estimates conducted in 2020-2022 provide baseline data on fish populations, and allow researchers to monitor and compare changes in these populations before and after construction of the CRCC. These estimates also allow opportunities to tag fish with Passive Integrated Transponder (PIT) tags used to evaluate fish movements. PIT tags use the same technology as those commonly used to identify pets, providing a unique ID for every fish that is detected by an antenna. PIT-tagged fish were released annually in the fall at two sites in the Colorado River and two sites in the Fraser River above Windy Gap Reservoir. Additionally, PIT-tagged fish were released in the spring throughout a four-mile stretch of the Colorado River below Windy Gap Reservoir. Since the study began in 2020, 4,234 fish have been PIT tagged in the Colorado and Fraser rivers, including 3,138 Brown Trout, 611 Rainbow Trout, 6 Cutbows (hybrids of Cutthroat Trout and Rainbow Trout), and 479 Mottled Sculpin. Mottled Sculpin are currently absent downstream of Windy Gap Reservoir. The CRCC is intended to facilitate sculpin distribution, increasing the diversity of the Colorado River downstream of the reservoir. Left to right: 32-mm PIT tag for evaluating Brown Trout and Rainbow Trout movements in the Colorado and Fraser rivers; 12-mm PIT tag being inserted into a Mottled Sculpin; paired stationary antennas installed on the bottom of the river used to evaluate directionality of movement; antenna station containing readers for recording tags as they pass stationary antennas; mobile antennas deployed in the Fraser River. COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us �Monitoring Movement with Stationary and Mobile Antennas Movements of PIT-tagged fish are passively monitored using two stationary antenna sites in the Colorado River below Windy Gap Reservoir and one stationary antenna site at the confluence of the Colorado and Fraser rivers above Windy Gap Reservoir. Paired antennas were installed on the bottom of the river to allow researchers to determine direction of movement, depending upon which of the two antennas a fish passes first. The antennas are connected to readers that store the date and time for every tag detected and are operated continuously 24 hours a day, 365 days a year. Antennas constructed in the bottom of rafts use GPS sensors to actively locate PIT-tagged fish in the Colorado and Fraser rivers in April, July, and October. These mobile antennas allow researchers to determine the location of sedentary fish such as Mottled Sculpin or certain age classes of Brown Trout and Rainbow Trout that move shorter distances, making it less likely that they would be detected as a stationary antenna site. Data collected by the stationary antennas have provided some valuable insights into fish movement within the study area. Generally, fish move more often at night than during the day, especially Brown Trout, likely to avoid predators. Brown Trout and Rainbow Trout exhibit seasonal movements concurrent with their spawning seasons, Brown Trout in the fall and Rainbow Trout in the spring. Movement distance and timing is also dependent on fish size. Mottled sculpin do not exhibit seasonal movements, but rather move sporadically throughout the year. Visualizing the Data Maps such as this one depicting tagged fish release sites in colored stars and the location of fish from those release sites in the same colored circles allow researchers to draw conclusions about the distances fish have moved and overall movement patterns of the populations as a whole. Using data obtained from the mobile antenna surveys, we have seen that, upstream of Windy Gap Reservoir, some fish released in the Fraser River moved into the Colorado River, and vice versa, and that long distance movements are made in the Colorado River below Windy Gap Reservoir during certain times of year. Data collected from the stationary antenna sites, mobile antenna surveys, and recaptures of tagged fish during the population estimates will be used to obtain estimates of detection, survival, and movement probabilities, by species and fish size, before and after construction of the CRCC. COLORADO PARKS & WILDLIFE • 317 West Prospect Road, Fort Collins, CO 80526 • (970) 472-4436 • cpw.state.co.us � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Fact Sheets Type The nature or genre of the resource Fact Sheet Format The file format, physical medium, or dimensions of the resource application/pdf Description An account of the resource CPW Fact Sheets Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Aquatics Research Fact Sheets Description An account of the resource One to two page summaries of aquatics research projects. Print copy located in CPW Research Library: FILE Fact Sheets Aquatics Creator An entity primarily responsible for making the resource <a href="https://cpw.state.co.us/aquatic-research">CPW aquatics researchers</a> Rights Information about rights held in and over the resource <a href="http://rightsstatements.org/vocab/InC-NC/1.0/">IN COPYRIGHT - NON-COMMERCIAL USE PERMITTED</a>