2018 Sturgeon For Tomorrow Research

Lake Sturgeon Research and Stocking Summary

By Doug Larson, Research Assistant I, Michigan Department of Natural Resources, Michigan State University

The 2018 Black Lake research season began on May 8thwhen Michigan State University (MSU) and Michigan Depart-ment of Natural Resources (MDNR) researchers captured six adult Lake Sturgeon ascending the Upper Black River. This was a very late start compared to previous years, owing to the Late-April snowstorms. Radio Frequency Identification (RFID) data suggests that Lake Sturgeon Adults were in the river on May 2nd, 2018, with ~ 40 fish reaching Klieber Dam before the river was accessible. Once the dam was able to lower the spillway, MSU staff was able to sample from May 8ththrough the end of the run on May 23rd.

A total of 200 adult Lake Sturgeon were captured during the spawning season, of which 34 were captured for the first time (17.00%). Of the first time captures, no fish showed signs of hatchery origin. The largest single day capture was on May 17th, where the crew sampled 31 fish. The largest fish captured this year was a 6.1-foot female that weighed 143 pounds. Gametes were collected from spawning Lake Sturgeon and transported to the Stream-side Rearing Facility for fertilization and rearing. In total 1,145 unique individ-ual Lake Sturgeon have been captured in the Upper Black River since 2001.

In addition to raising eggs in the hatchery, wild larval Lake Sturgeon were captured as they drifted downstream. Previous research conducted by MSU and MDNR found that wild larvae represent the highest quality genetic source stock, so MSU and MDNR make an effort to fulfil all stocking quotas with fish captured in the wild, where possible. This year, larval drift sampling began on May 23rdand continued until June 24th. Researchers captured 46,931 wild dispersing larvae at Site D, the most captured in a single season. As part of a graduate project, staff collected larval fish at two additional sites: The historical site for the sawmill and site C. In total researchers caught 103,968 drifting larvae across 32 drift nights.

In 2018, 541 Lake Sturgeon were released into the Black River. All fish that were stocked into the Black River were implanted with a passive inte-grated transponder tag, which will aid future management efforts. In addition, 537 Lake Sturgeon were released into Mullet Lake, all of which were im-planted with a PIT tag.

At the direction of the Lake Sturgeon committee and in collaboration with the United States Fish and Wildlife Service, Black Lake Sturgeon for Tomorrow, and Michigan Sea Grant, 139, 136, 133, and 136 fall fingerling Lake Sturgeon were released into the Titabawassee, Flint, Shiawassee and Cass Rivers, re-spectively as part of an ongoing rehabilitation and research effort. This project will continue at an approximate density of 125 Lake Sturgeon from the Black River Streamside Rearing Facility for the foreseeable future.

The Sturgeon released in 2018 reached an average length of over 7 inches. Increased size at stock out can be attributed to an improved feeding strategy developed and published by John Bauman.

During the fall juvenile Lake Sturgeon assessment, we captured 40 fish across 5 nights. Researchers conducted a mark-recapture assessment across four transects from the mouth of the river to Red Bridge nightly from dusk un-til completion during the week of July 30th, 2018. This assessment resulted in a calculated population estimate of 41; (95% CI; Lower: 32, Upper: 58) Lake Stur-geon in the lower 4-km of the Upper Black River.