Umatilla River Basin Avian and Non-Native Fish Predation Assessment

Project objective was to 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. 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 (79 river miles). Naturally produced endemic steelhead smolt survival within the Umatilla River (from river mile 79 downstream to the mouth) have been monitored annually since 2009.



Pelican counts from aircraft were started along the Umatilla River in April of 2023. Surveys occur weekly during April-June and once a month from July-October. Few pelicans were observed from July -through March. A seasonal maximum of 588 pelicans were observed on May 24, 2024, with 2026 annual maximum of 381 pelicans observed on April 24, 2026. Pelicans were not observed during October-March in the Umatilla River (2023-2024). No flights were conducted from November-February (2025-26) because no pelicans were observed during those months in the past. Throughout the smolt migration season, many pelicans were observed actively feeding from the Umatilla River during all four years.



To estimate pelican predation on smolts, we fed PIT tagged fish to pelicans to determine PIT tag deposition rates on Badger, Foundation, and other Islands. We fed PIT tagged fish to pelicans at Three Mile Falls Dam forebay, Westland Dam, and near Pendleton (2023-2025). During 2025, we documented 1165 PIT tagged fish that were consumed by pelicans out of 1188 attempts. Few pelicans would eat PIT tagged fish at the Westland and Pendleton sites during 2025. Real Time Research crews surveyed the Columbia River Islands for PIT tags and reported their detections to PTAGIS.



We combined PIT tag deposition rates, Real Time Research’s PIT tag detection probability rates and the known number of PIT tagged released salmon and steelhead each year to estimate pelican predation on Umatilla origin smolts. Considerable variability in predation rate estimates occurred. PIT tag groups ranged from>1% to >30% predation by pelicans. In general, natural origin Chinook smolts had lower predation rates than summer steelhead smolts. The results from the PIT tag deposition rates show steelhead stocks are more vulnerable to predation,



We began tagging pelicans with cellular GPS tags to better understand their responses to management actions such as falconry and other hazing efforts (June 2026). Telemetry can provide additional information about daily, seasonal, and annual movements and the location of important areas for breeding, feeding, resting, and wintering. TWe finalized a pelican telemetry plan during this reporting period to address these questions. Proposed work was shared with CRITFC, and staff from Washington, Oregon, Yakima Nation, and the US Fish and Wildlife Service to build consensus and refine the study plan and permit application. We also contracted with an ornithologist with experience capturing and banding birds to assist our telemetry project development, permitting, and deployment. The team gained direct experience with the capture and tagging of large birds and pelicans during the summer of 2025. The pelican telemetry study plan was sent to collaborators and management agencies staff for review.



Note: This project occurred in combination with project 23-Umat-0

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.