Whitefish Biology, Distribution, and Fisheries in the Yukon and Kuskokwim River Drainages in Alaska: a Synthesis of Available Information Alaska Fisheries Data Series Number 2012-4

Whitefish species in Alaska are subject to intensive subsistence fisheries everywhere they occur, commercial fisheries in certain places, and limited sport fisheries. Our understanding of whitefish biology comes primarily from studies of the same or similar species in other places, although some biological studies have taken place locally. Whitefish fisheries in the Yukon and Kuskokwim River drainages in Alaska have been documented in numerous anthropological and social science publications and in subsistence harvest surveys, but usually without species distinctions. Scientific sampling work since the 1960s has been reasonably effective at describing the species that are present and their distributions within the two drainages, but our understanding of populations, migrations, and demographic distribution among habitats is poor. We are just beginning to understand that major spawning migrations into upstream reaches of the drainage occur each summer and fall, juvenile and non-spawning fish dominate the lower reaches of both rivers and the coastal areas, and mature and spawning fish dominate the upper reaches. A small number of whitefish spawning areas have been identified in gravel substrate reaches of main-stem and tributary rivers in both turbid and clear water. Genetics work with whitefish species has focused more on taxonomy and biogeography issues than for management applications. With two exceptions in the entire Yukon and Kuskokwim River drainages, population abundance data are absent. Our ability to protect essential habitats for whitefish populations is growing with the improved understanding of their spawning destinations and life histories. Our ability to monitor whitefish population trends and to make effective harvest regulations, however, is very limited at this point.