Distribution and Movement Patterns of Chinook Salmon Returning to the Yukon River Basin in 2000-2002

The National Marine Fisheries Service's Alaska Fisheries Science Center uses the NOAA Technical Memorandum series to issue informal scientific and technical publications when complete formal review and editorial processing are not appropriate or feasible. Documents within this series reflect sound professional work and may be referenced in the formal scientific and technical literature. In the process of converting the original printed document into Adobe Acrobat .PDF format, slight differences in formatting can occur; page numbers in the .PDF may not match the original printed document; and some characters or symbols may not translate. This document is being made available in .PDF format for the convenience of users; however, the accuracy and correctness of the document can only be certified as was presented in the original hard copy format. iii ABSTRACT A radio telemetry study was conducted on Yukon River chinook salmon from 2000 to 2002 to provide information on stock composition and timing, migration patterns, and the location of important spawning areas. Feasibility work in 2000-2001 determined that drift gill nets were effective for capturing adequate numbers of fish in the lower river, and that the fish responded well to the capture and tagging procedures based on their subsequent upriver movements. A large-scale tagging and basin-wide monitoring program was conducted in 2002. Most (751, 97.8%) of the 768 fish tagged resumed upriver movements, with 270 fish harvested in fisheries and 481 fish tracked to upriver areas using remote tracking stations and aerial surveys. Stock composition estimates were developed for the 2002 chinook salmon return based on the distribution of daily releases of radio-tagged fish weighted for abundance and adjusted for fish harvested in fisheries. The chinook salmon run was composed primarily of Tanana River (20.9%) and upper basin (66.0%) stocks. Canadian-origin fish comprised the largest component of the return (53.4%), with most traveling to reaches of the Yukon River (50.7%) and only small numbers to the Porcupine River (2.7%). Canadian fish in the Yukon River returned to large headwater tributaries (35.5%), small tributaries associated with the main river (4.6%) and reaches of the Yukon River main stem (10.6%). Chandalar River and Sheenjek River fish (5.9%) were important U.S. stocks in the upper basin. Tanana River fish were predominantly Chena River, Salcha River, and Goodpaster River stocks (18.8%), with small populations located in other tributaries. Middle basin fish traveling to the Koyukuk, Melozitna, Nowitna, and Tozitna rivers were a minor component …