Species Composition of Deep-Water Ciscoes (Chubs) in Commercial Catches From Michigan Waters of Lake Superior
James W. Peck
Bloaters were the most abundant chub in the total samples from each of the fishing grounds, ranging from 51% at Marquette to 87% at east Keweenaw. Kiyi made up 38-40% of the chubs sampled from west Keweenaw, north Keweenaw, and Marquette, but only 7% of the chubs from the east Keweenaw grounds. Shortjaw ciscoes comprised 6% of the chubs from the fishing grounds around the Keweenaw Peninsula and 11% of the chubs sampled at Marquette. No shortnose or blackfin ciscoes were found in any of the samples. I could not establish any definite differences in the species composition between the three seasonal sampling periods on each fishing ground. There was no observed change in bloater or kiyi composition between years but shortjaw ciscoes were more abundant in 1974 than in either 1975 or 1976 on all fishing grounds and for most seasons. I could not establish species composition by depth interval because the depth range of individual net sets on each ground overlapped. However, bloaters made up a much greater percentage of the catch on the shallower east Keweenaw grounds than they did on the deeper west Keweenaw, north Keweenaw, and Marquette grounds.