Fish Community Survey of the Salmon and Aniak Rivers, 2025

The Kuspuk School District annually hosts a student raft trip down the Salmon and Aniak rivers within the Kuskokwim River basin in Alaska. The event is known as the “Math and Science Expedition” (MSE). Participants in the 10- to 12-day excursion include approximately 30 students in grades 7 through 12, accompanied by several adult mentors and fisheries biologists. Since 2014, students have explored fish ecology by conducting a standardized survey of the juvenile fish community at 4 or 5 stations. At each of the four stations, students deployed six G40 minnow traps baited with salmon eggs held in a perforated container. Traps are set overnight with a total soak time ranging from about 12 to 15 hours. Under supervision, individual fish are identified to species, measured for paired fork-length (mm) and weight (g), and then released. When large numbers of fish are caught at a given station, length and weight are only measured for a subset of fish in order to reduce processing and holding times. In these instances, the aim is not to exceed 80 paired weight-length measurements for Chinook and 120 for coho and other species. Fish not measured are still counted by species and recorded in order to document the total number of fish caught as an index of fish abundance at that station. Juvenile Chinook are typically age-1, and juvenile coho occur as age-1 and age-2. Dolly Varden occurs as juvenile and a dwarf forms. Catches include small numbers of juvenile sockeye and rainbow trout. For each year sampled, the KNB website includes both a spreadsheet with catch data for that one year, plus a PDF file trip report with summary analysis. Sampling was not conducted in 2020 due to COVID. Data from 2022 is not included due to sampling irregularities, though a trip report is included explaining the circumstances.