Biology of round whitefish Prosopium cylindraceum (Coregonidae) of the Anadyr River

Abstract

The recent state of the population of round whitefish Prosopium cylindraceum from the Anadyr River is described. Age composition of the catches of round whitefish remained almost without changes over the 35-year observation period. During this period, the proportion of large fishes (>380 mm in body length) slightly decreased, and the average body length of sexually mature individuals had become smaller. Possible reasons of interannual changes of the size-age composition of the catches and growth rate of the fish are discussed. A main factor determining growth variation of the fish is the abundance of chum salmon Oncorhynchus keta that migrated. The abundance of the round whitefish of the Anadyr River remains at a stable level (except the area of Markovo village) over a long time, and this population is hardly exploited.