Summer ecology and behavior of the grayling of McManus Creek, Alaska

Abstract

A study of the summer ecology and behavior of the Arctic Grayling was undertaken on the summer population of McManus Creek, Alaska. An effort to determine the distribution and the patterns of the fish’s movements in the stream was made. The grayling spent the summer months in pools where they established feeding territories. Within each feeding territory a feeding range, where all feeding activities took place, was found. In each pool a hierarchial ordering based on a dominant subordinate relationship existed. This hierarchy was established and maintained by a series of displays. The grayling of McManus Creek were found to feed solely on the surface and at mid-depth. The food items consisted both of flying insects and aquatic insects, the latter making up the largest portion of their diet. It appeared that the fish relied primarily upon benthic drift for nutrition. Being visual feeders, the fish were unable to utilize the large numbers of organisms known to drift during periods of high and muddy water.