Great Lakes Fishery Commission

Updated 2024-11-26 20:16:08

Lake Superior -> 6.0 Lake Sturgeon -> Adult Lake Sturgeon Abundance

6.1.1 In each tributary, there are 1,500 adults capable of spawning with a ~1:1 (male:female) sex ratio or there are 400 adults annually spawning with a 1:1 to ~4:1 (male:female) sex ratio.

The Fish Community Objective for Lake Sturgeon in Lake Superior is "Rehabilitate and maintain spawning populations of lake sturgeon that are self-sustaining throughout their native range." In A Lake Sturgeon Rehabilitation Plan for Lake Superior, self-sustaining is defined as a population with a minimum of 1,500 mature adults, a roughly equal sex-ratio, 20 or more year-classes of adult-fish, evidence of annual reproduction through collection of viable eggs, and measurable recruitment of age 0-5 fish.  The indicator used to evaluate progress towards reaching the fish community objective for lake sturgeon is in each tributary where historic spawning was documented there are 1,500 adults capable of spawning with a roughly 1:1 (male:female) sex ratio or there are 400 adults annually spawning with a 1:1 to ~4:1 (male:female) sex ratio.  Populations meet indicator criteria in 2 of 19 historic spawning tributaries (Bad River, Wisconsin, and Sturgeon River, Michigan).  Mature adults are found in spawning runs in 11 Lake Superior tributaries, but not all meet full indicator criteria. There are no spawning assessments on many tributaries.

The Minnesota Department of Natural Resources conducts annual spawning Lake Sturgeon surveys on the St. Louis River using boat electrofishing and dip-netting during the spring spawning run.  Adult Lake Sturgeon are also sampled using hook-and-line sampling, standardized MNDNR Fisheries survey netting, and standardized juvenile Lake Sturgeon netting surveys.  Although, not correlated to true abundance the increasing directed effort towards Lake Sturgeon sampling since 2006 has resulted in over 1,924 individual Lake Sturgeon being sampled in the St. Louis River (Figure 1) spawning population.  Additional details on Lake Sturgeon rehabilitation efforts in Minnesota can be found here. 

Figure 1. Number of adult lake sturgeon sampled annually in the St. Louis River Estuary, Duluth, MN. Since 2006, over 2,300 lake sturgeon using a variety of techniques including boat electrofishing (49% of total catch), dip-netting on spawning grounds (41% of total catch), standardized MNDNR Fisheries survey nets (7% of total catch), angling (1.3% of total catch), and standardized juvenile lake sturgeon survey netting in Lake Superior (1.1% of total catch).