|Document Type:||Chapter or Section|
|Type of Book:||Technical|
|Section or Chapter Title:||Appendix C: NOAA Fisheries report: Caspian tern predation on juvenile salmonid outmigrants in the Columbia River estuary|
|Book Title:||Caspian tern management to reduce predation of juvenile salmonids in the Columbia River estuary|
|Author:||T. P. Good, K. Barnas, D. M. Marsh, Michelle M. McClure, Brad A. Ryan, Benjamin P. Sandford, Edmundo Casillas|
|Publisher:||Report of the U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers, and U.S. National Marine Fisheries Service. Portland, Oregon|
• Relatively new human–constructed islands in the Columbia River estuary have provided breeding habitat for Caspian terns, where they have been able to successfully exploit juvenile salmonids as a food resource.
• The effect of Caspian tern predation varies between years, varies among salmonid species, is greatest on steelhead, and is lowest on wild yearling Chinook.
• Caspian tern predation on juvenile salmonids reduces salmon population growth rate and thus recovery; however, removing all tern predation will not, by itself, lead to full recovery of any listed salmon and steelhead stock.
• The effect of Caspian tern predation on recovery may be comparable to fish passage improvements at Columbia River dams and harvest reductions for some Evolutionarily Significant Units.
• Relocating Caspian terns to habitat closer to the mouth of the Columbia River significantly reduced predation impact on juvenile salmon.
• Additional PIT tag data needs to be collected and evaluated to validate initial predation rates at East Sand Island.
|Notes:||Full text available from U.S. Fish and Wildlife Service Migratory Birds and Habitats Program: www.fws.gov/pacific/migratorybirds/nepa.html|