Capture of Lake Sturgeon with Setlines in the St. Clair River, Michigan

Abstract

Setlines were constructed and used to capture lake sturgeon Acipenser fulvescens in the St. Clair River, a Great Lakes connecting waterway. Particularly strong current, steep bottom contours, and water depths exceeding 18 m make traditional sampling methods in this area problematic. We constructed six setlines, each with 25 hooks (a total of 150 hooks), for a cost of about US$60 each. Hooks were baited with a variety of cut and whole fish. Sixty-seven sets in May and Jun of 1997 caught 84 lake sturgeon. The only other fish caught was one northern pike Esox lucius. Round goby Neogobius melanostomus, an introduced exotic species, was the most successful bait used. Lake sturgeon caught on setlines ranged in weight from 0.8 kg to 45.5 kg. Most lake sturgeon were hooked in the mouth and experienced little visible damage or stress, but about 20% of the fish were hooked outside the mouth (snagged) and in a few cases considerable bleeding and tissue damage occurred. The highest incidence of snagging coincided with peak spawning activity and may be related to a behavioral change associated with spawning. We found that setlines provided an effective, low-cost method for collecting lake sturgeon in the difficult physical conditions present in the St. Clair River.