Umatilla River Basin Avian and Non-Native Fish Predation Assessment

Estimate the annual impact of avian and non-native fish predators on ESA listed Mid-Columbia River steelhead smolts and reintroduced spring Chinook salmon smolts in the Umatilla River beginning with American white pelicans in 2023. Effects of predation on salmon and steelhead was identified as a critical uncertainty in the Columbia River Anadromous Fish Restoration Plan of the Nez Perce, Umatilla, Warms Springs, and Yakama Tribes, http://www.critfc.org. Umatilla River summer steelhead are considered a critical component of the Mid-Columbia steelhead Evolutionarily Significant Unit, which is listed as a threatened population under the federal ESA. Determine if American white pelicans are contributing significantly to the high mortality of summer steelhead smolts and reintroduced spring Chinook salmon within the Umatilla River (75 river miles). Naturally produced endemic steelhead smolt survival within the Umatilla River (from river mile 79 downstream to river mile 4) has been monitored annually since 2009 and has been below 10% during some years with survival rates below 50% most of the time. A large increase in pelicans occurred after the creation of Badger Island in the Columbia River in 1993. Subsequently, the artificial island became the location of a pelican breeding colony with estimates of as many as 5,594 breeding pelicans in 2018. Collect 156 American white pelicans during the primary smolt monitoring season, March 1 through May 31, 2023. Twelve pelicans will be collected each week for thirteen weeks. Examine pelican digestive tract contents to determine the proportion of fish consumed that are salmon and steelhead smolts. Determine the average number of steelhead and salmon smolts eaten per pelican for each of the 13 weeks of primary smolt migration (March 1-May 31). Conduct weekly bird counts to estimate the number of pelicans using the Umatilla River for feeding and resting during the primary smolt out-migration season. Use weekly pelican counts (this project), portion of salmonids consumed (this project) and pounds of fish consumed per bird per day (3.97 lbs.) to determine the total annual impact of American white pelican predation on steelhead and salmon smolts in the Umatilla River Basin during the primary smolt migration period. Determine the deposition rate of PIT tags on Badger Island and other pelican roosting areas from pelicans that feed in the Umatilla River. Feed pelicans with PIT tagged suckers and other non-game fish and non-native fish collected at the Three Mile Falls Dam Fish Trap. Query the PTAGIS database for PIT tag detections derived by future surveys of pelican nesting and resting areas conducted by other projects. ODFW fish pathologists will examine pelican digestive tracts for parasites that might impact salmon and steelhead. Identify parasites and their respective loads in pelican digestive tracts. Determine if there are salmonid related parasites at sufficient abundances in American white pelicans to significantly impact salmon and steelhead.



Worksite #1 Proposed Work:

Umatilla River- Estimate the annual impact of American white pelican predation on ESA listed Mid-Columbia River steelhead smolts and reintroduced spring Chinook salmon smolts in the Umatilla River. Collect 156 American white pelicans during the primary smolt monitoring season, March 1 through May 31 all along the worksite in the Umatilla River from the mouth to river mile 73. Examine digestive tract content to determine the proportion of fish consumed that are salmon and steelhead smolts. Conduct weekly bird counts to estimate the number of pelicans using the Umatilla River for feeding and resting during the primary smolt out-migration season. Use pelican counts and consumption rates to determine the total annual impact of American white pelican predation on steelhead and salmon smolts in the Umatilla River Basin. Examine pelican digestive tracts for parasites that might impact salmon and steelh

Provide fisheries managers with empirical data regarding the impact of American white pelicans to smolts in the Umatilla Basin. Determine if American white pelicans are contributing significantly to the high mortality of ESA listed Mid-Columbia summer steelhead smolts and reintroduced spring Chinook salmon within the Umatilla River (79 river miles). Determine if there are salmonid related parasites at sufficient abundances in American white pelicans to significantly impact salmon and steelhead. The intent is to examine the potential impacts of American white pelicans on smolt survival beginning in 2023 and transition to examining the potential impacts of non-native predatory fish on smolt survival in subsequent years.