RTR (prime contractor) and its partners were one of three vendors selected to provide biological and environmental services to the U.S. Army Corps of Engineers – Walla Walla District as part of a 5-year Multiple Award Task Order Contract of Indefinite Delivery, Indefinite Quantity (MATOC IDIQ). As part of this contract, 25 Task Orders (TO’s) were issued of which RTR was awarded the majority (14 TO’s), totaling over 6 million in funding. This work included studies on Pacific lamprey and adult salmonid passage at hydroelectric dams, juvenile salmonid survival investigations, avian predation research and management implementation, as well as numerous other studies involving fish of conversation concern in the Columbia River basin.

Over the past three decades, RTR and its partner (Oregon State University) have been the principal investigators of avian predation on ESA-listed juvenile salmonids in the Columbia River basin. Funding for these studies has come from many different agencies, but primarily from the federal government (i.e., U.S, Army Corps of Engineers, Bonneville Power Administration, U.S. Bureau of Reclamation, NOAA Fisheries). Our early work on these studies quantified the number and percentage of out-migrating juvenile salmonids that succumbed to bird predation in the Columbia River basin and elsewhere along the Pacific Coast of North America. After identifying the bird species and colonies posing the greatest threat to salmonid survival, we worked with the resource management agencies to develop and implement management plans to reduce bird predation on salmonid smolts. Currently, we are conducting research, monitoring, and evaluation of these plans to inform adaptive management to maximize the benefits to salmonid survival in managing birds, while at the same time, not putting the managed bird populations at risk.

RTR (prime contractor) and its partner (Biomark) investigated the feasibility and efficacy of using Passive Integrated Transponder (PIT) tag detection arrays at key locations in the Sacramento-San Joaquin River Delta to estimate the numbers and run timing of juvenile salmonids moving through that system. The locations of interest in the Central Valley were deeper in water depth than most sites previously monitored, and in some cases, were subject to tidal influence that reversed the direction of flow. To monitor the deeper locations as part of this study, our partner developed a PIT-tag antenna housed in a hydrofoil that was deployed vertically from a barge. Multiple hydrofoils were then deployed side-by-side to increase the horizontal sample volume. In addition, a traditional bottom-mounted antenna was positioned under each hydrofoil barge. The combination of hydrofoil and bottom-mounted antennas allowed us to evaluate the efficacy of each deployment approach to monitor PIT-tagged juvenile fish in water deeper than 3m.