Yellowstone Fisheries & Aquatic Sciences Annual Report 2003 Thorofare Creek, October 2003. ellowstone National Park’s Yellowstone Lake is whirling behavior, abnormal feeding, and increased home to the premier surviving inland cutthroat vulnerability to predation, was first detected in Yellowstone Y trout fishery in North America. Two significant Lake in 1998, and in the Firehole River in 2000. This threats to the native Yellowstone cutthroat trout, discovered devastating disease further threatens already declining over a five-year period during the 1990s, irreversibly Yellowstone cutthroat trout populations. Although whirling altered the future of this thriving and diverse ecosystem. disease is currently believed to be concentrated in the Without swift, continuing action, negative effects on this northern regions of the Yellowstone Lake watershed, several trout population—a keystone energy source for numerous other tributaries have already been identified as at high risk. mammal and bird species and a recreational focus for In addition to native trout preservation, aquatics visitors—have the potential to produce ecosystemwide program goals include restoration of isolated but genetically consequences. pure westslope cutthroat trout, monitoring to track aquatic Predatory, non-native lake trout were likely illegally ecosystem health and expedite early warnings for other introduced to the lake in 1988 and not discovered until invasive exotic species, and encouragement of public 1994. They can consume 50–90 Yellowstone cutthroat trout involvement in various fisheries programs. per capita annually. Without heightened and maintained The stakes are high, raising the bar for innovative management efforts, they have the potential to decimate management and fundraising. The increased magnitude the Yellowstone Lake fishery in our lifetime. Lake trout also of the problems faced by the park’s fisheries and the occupy an ecological niche unavailable to cutthroat-eating accelerated rate at which they are occurring are straining predators, imperiling the many species, such as grizzly bears, Yellowstone’s resources. This annual report describes historic bald eagles, and river otters, that depend on the cutthroat for and continuing park aquatics programs as well as specific survival. initiatives during 2003. It is a scientific call for action— Whirling disease, a parasite that attacks the developing action urgently needed to assure cutthroat trout survival and cartilage of young fish resulting in skeletal deformity, overall fishery health in Yellowstone National Park. Yellowstone Fisheries & Aquatic Sciences Annual Report 2003 © MIMI MATSUDA Yellowstone cutthroat trout Todd M. Koel, Jeffrey L. Arnold, Patricia E. Bigelow, Philip D. Doepke, Brian D. Ertel, and Daniel L. Mahony National Park Service Yellowstone Center for Resources Yellowstone National Park, Wyoming YCR-NR-2004-03 Background 6 2003 Summary 8 Yellowstone Cutthroat Trout Preservation 10 Westslope Cutthroat Trout Restoration 16 Stream Fishery Surveys and Fish Health 18 Aquatic Ecosystem Health 21 Impacts of the New Zealand Mudsnail in Waters of Yellowstone National Park 26 Angling in the Park 28 Public Involvement 30 Collaborative Research 31 Literature Cited 33 Appendices 34 Suggested citation: Koel, T. M., J. L. Arnold, P. E. Bigelow, P. D. Doepke, B. D. Ertel, and D. L. Mahony. 2004. Yellowstone Fisheries & Aquatic Sciences: Annual Report, 2003. National Park Service, Yellowstone Center for Resources, Yellowstone National Park, Wyoming, YCR-NR-2004-03. Title page and inside back cover art courtesy Mimi Matsuda. Front cover photo captions (left to right): NPS Aquatic Ecologist Jeffrey Arnold collecting aquatic macroinvertebrates; Arctic grayling from Grebe Lake, upper Gibbon River system (photo by Timothy Bywater); NPS volunteer Phillip Hurst radio tracking cutthroat trout on the upper Yellowstone River. Back cover photo captions (left to right): NPS stream fisheries crew conducting a survey of Slough Creek; native dragonfly flame skimmer along the Firehole River (photo by Jeffrey Arnold); non-native lake trout removed by gillnetting on Yellowstone Lake (photo by Patricia Bigelow). Facing page photo caption: NPS Fisheries Technician Barbara Rowdon with a lake trout removed from Breeze Channel, Yellowstone Lake (photo by Patricia Bigelow). All photos in this report not otherwise marked are by Todd Koel. Contents BACKGROUND ........................................................................................ 2 MAP OF MAJOR SURFACE WATERS OF YELLOWSTONE NATIONAL PARK ......... 4 SUMMARY .............................................................................................. 4 YELLOWSTONE CUTTHROAT TROUT PRESERVATION.................................... 6 Maintaining long-term monitoring programs.....................................7 Removal of non-native lake trout from Yellowstone Lake ...................8 Understanding the effects of whirling disease ...................................10 Hydroacoustic surveys to document population change ...................11 Status of cutthroat trout in the upper Yellowstone River...................11 WESTSLOPE CUTTHROAT TROUT RESTORATION ...................................... 12 Population surveys ...........................................................................12 Genetics surveys...............................................................................12 Restoration potential........................................................................13 STREAM FISHERY SURVEYS AND FISH HEALTH.......................................... 14 Population surveys ...........................................................................14 Monitoring associated with road reconstruction...............................14 Surveys for fish health ......................................................................16 Genetics surveys...............................................................................16 AQUATIC ECOSYSTEM HEALTH............................................................... 17 Invasive aquatic exotic species threaten the park ...............................17 Long-term water quality monitoring ................................................17 Limnology of Yellowstone Lake........................................................19 Water quality associated with winter use...........................................19 Macroinvertebrate monitoring .........................................................20 IMPACTS OF THE NEW ZEALAND MUDSNAIL IN WATERS OF YELLOWSTONE NATIONAL PARK ........................................................ 22 ANGLING IN THE PARK.......................................................................... 24 Trends from the volunteer angler report cards...................................24 PUBLIC INVOLVEMENT........................................................................... 26 Yellowstone volunteer flyfishing program .........................................26 Long-term volunteer assistance.........................................................26 Educational programs ......................................................................26 COLLABORATIVE RESEARCH ................................................................... 27 Projects by graduate students............................................................27 Other research and collaboration......................................................27 ACKNOWLEDGMENTS............................................................................. 28 Literature Cited.....................................................................................29 APPENDICES ......................................................................................... 30 i. Fish species list ..............................................................................30 ii. Long-term volunteers...................................................................30 iii. Seasonal staff...............................................................................30 NPS PHOTO Background reated in 1872, Yellowstone National Park was for several years the only C wildland under active federal management. Early visitors fished and hunted for subsistence, as there were almost no visitor services. At the time, park fishes were viewed as resources to be used—by sport anglers and to provide park visitors with fresh meals. Fish- eating wildlife, such as bears, ospreys, otters, and pelicans, were regarded as nuisances, and many 1 were destroyed as a result. U.S. Fish and Wildlife Service personnel removing fish To supplement fishing and counteract from a Yellowstone Lake gillnet in 1981. this “destructive” consumption by wildlife, a fish “planting” program was established in Yellowstone. Early park superintendents recreational angling became a long-term, noted the vast fishless waters of the park, and accepted use of national parks throughout the immediately asked the U.S. Fish Commission country. In Yellowstone, fisheries management, to “see that all waters are stocked so that the as we understand the term today, began with the pleasure seeker can enjoy fine fishing within U.S. Army and was assumed by the National a few rods of any hotel or camp.”2 The first Park Service in 1916. Fish stocking, data fishes from outside the park were planted in gathering, and other monitoring activities began 1889–1890, and included brook trout in the with the U.S. Fish Commission in 1889, were upper Firehole River; rainbow trout in the continued by the U.S. Fish and Wildlife