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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Fish Ecology
DIET OF ARCTIC GRAYLING IN LARGE AND SMALL STREAMS OF THE NORTH SLOPE, ALASKA.
K.M. Buzby and L.A. Deegan. The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02540
In streams of the North Slope of Alaska, arctic grayling (Thymallus arcticus) segregate according to size. Adult fish primarily occupy large streams with juveniles in the smaller first and second order streams. Juvenile fish may be actively choosing these smaller streams or are excluded from the larger rivers by adult fish. We examined the stomach contents of fish from 2 first order streams and from the 4th order Kuparuk River to assess the quality of the food resources in large and small streams. The diet of fish in both small streams was heavily dependent on chironomids, often exceeding 80% of the prey items ingested. Grayling in the larger stream consumed a more varied diet consisting of chironomids and stonefly, caddisfly and mayfly larvae. The biomass consumed was comparable in all streams early in the summer. Late in the summer fish in the larger stream consumed twice the biomass despite similar numbers of prey items. Food resources in the larger stream appear to be of better quality late in the summer, which may be critical to grayling as they prepare for the arctic winter and would indicate that the adult fish are probably excluding the juveniles from the larger streams.
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