Status and trends in the Lake Superior fish community, 2020

By: , and 



The Lake Superior fish community within Management Unit WI-2 was sampled in July 2020 with daytime bottom trawls at 11 nearshore stations. The 11 locations sampled were long-term monitoring sites that had been annually sampled since 1974. In 2020, the number of species collected at each site ranged from 0 to 13, with a mean of 6.3 and median of six. All comparisons to 2020 results were limited to past collections from Management Unit WI-2. Mean total biomass was 10.5 kg/ha which was similar to the average observed over the past 10 years (10.3 kg/ha), less than averages over the past 20 and 30-years, 15.3 and 19.8 kg/ha respectively, and higher than the average observed from 1974-84 (4.7 kg/ha). Average biomass in 2020 was highest for Bloater (6.2 kg/ha), Lake Whitefish (2.3 kg/ha), and Cisco (0.9 kg/ha). Rainbow Smelt biomass averaged 0.3 kg/ha. Year-class strength, as measured by age-1 densities, was well below the 5, 10, and 25-year averages for Bloater, Cisco, Lake Whitefish and Rainbow Smelt. Bloater averaged 1 age-1 fish/ha, Cisco, 0.2 age-1 fish/ha, Lake Whitefish, 15 age-1 fish/ha, and Rainbow Smelt 6 age-1 fish/ha. Cisco survival to age-1 has been near non-existent since the 2014- and 2015-year classes and the last moderate sized year class was in 2009. This lack of survival has yet to be adequately explained and continues to be a major concern of fishery managers due to Cisco’s importance in ecosystem dynamics and value to the commercial fishery.

Study Area

Publication type Report
Publication Subtype Organization Series
Title Status and trends in the Lake Superior fish community, 2020
Year Published 2022
Language English
Publisher Great Lakes Fishery Commission
Contributing office(s) Great Lakes Science Center
Description 21 p.
Country Canada, United States
Other Geospatial Lake Superior
Google Analytic Metrics Metrics page
Additional publication details