The shortjaw cisco (Coregonus zenithicus) was a Category 2 candidate species under consideration for listing by the U.S. Fish and Wildlife Service (FWS) under the Endangered Species Act as amended. The shortjaw cisco was listed as Threatened by the Federal Committee On Status of Endangered Wildlife in Canada, listed as Threatened by the Michigan Department of Natural Resources, and listed as Endangered by the Wisconsin Department of Natural Resources. Although the range of the shortjaw cisco once included all of the Great Lakes, its present range in the United States is limited to Lake Superior. In the early 1920s, shortjaw ciscoes were the most numerous deepwater ciscoes (Coregonus sp.) in commercial fish catches in Lake Superior, but by the early 1970s the shortjaw cisco composed only 6% of the commercial catch in most of Michigan waters. The current status of the shortjaw cisco in Lake Superior is currently unknown. The objective of our study was to compare relative abundances (catch-per-unit-effort in standardized gill nets) of shortjaw cisco in the historic reference period (1921-1922) and in the present (1999-2000). These comparisons will be made for each of five areas of the lake, which span the entire known range in the United States.

GLSC researchers found shortjaw ciscoes in three of the four areas sampled. No shortjaw ciscoes were collected in the Apostle Islands area. From the 1920s to the present, the backtransformed mean catch-per-unit-of-effort (CPUE=catch/305 m of 64-mm and 70-mm stretched mesh gill net/night) for shortjaw cisco declined by 95% at Marquette, 98% at Grand Marais, 99% at the Whitefish Bay, and at least 99.9 % at the Apostle Islands. CPUEs for shortjaw cisco at all locations combined were greater in 1921-1922 than in 1999-2000.