Cisco numbers up, might be a record year

Commercial and sports fishermen will be heartened to hear that the numbers of Lake Superior juvenile cisco caught in bottom trawl surveys this season are reaching epic numbers.

The surveys have been conducted by the U.S. Geological Survey (USGS).

As reported by the Minnesota Department of Natural Resources, “The number of one-year-old cisco in a haul is a huge indicator of the future adult population. Once cisco successfully reach one year of age, they’re likely to make it to adulthood (three years of age) and can live up to over 30 years old.

“Age one cisco have been hard to come by in recent years, with some years only yielding a single fish during trawl surveys around all of Lake Superior. Scientists on the USGS Research Vessel Kiyl haven’t seen numbers this high since at least 1984 and if high catches keep up, this may be a record-setting year.

“Cisco are an important prey fish for larger fish, lake trout. In recent years, Lake Superior hasn’t had as many prey fish for larger predator fish to eat. A boom in cisco is great news for the whole ecosystem.”

“Based on these findings, fisheries biologists can predict a large increase in adult numbers in three years in the commercial, sport and tribal fisheries (and maybe larger-sized predator fish!), making the USGS bottom trawl survey one of the most important surveys do to support management across Lake Superior.

“While the long, snowy winters were tough for Minnesotan’s the past two years, it may have been a boon for cisco. Colder water temperatures in the spring of 2022 may have allowed cisco egg hatching and zooplankton production (the tiny orgasms they eat as young fry) to match up well for the first time in years.”