2016 Sturgeon For Tomorrow Research

Lake Sturgeon Research and Stocking Summary

By Doug Larson, Research Technologist, Michigan State University

The 2016 Black Lake research season began on April 22nd when Michigan State University (MSU) and Michigan Department of Natural Resources (MDNR) researchers captured eleven adult Lake Sturgeon ascending the Upper Black River. This was an early start compared to previous years, though the early captures did not appear to reach spawning ripeness be-fore a string of cold weather pushed them out of the river.

A total of 198 adult Lake Sturgeon were captured through the spawning season, of which 41 were captured for the first time. The largest single day capture fell on May 3rd, where the crew sampled 34 fish. The largest fish captured this year was a 6-foot 4-inch female that weighed 112 pounds. Gamete were collected from spawning Lake Sturgeon and were transported to the Stream Side Rearing Facility for fertilization and rearing. In total, there have been 1,078 unique individual Lake Sturgeon captured in the Up-per 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 sam-pling began on May 18th and continued until there were three consecutive unsuccessful capture nights, which fell on July 1st. In total, researchers cap-tured 4,053 wild dispersing larvae.

In 2016, 500 Lake Sturgeon were released into the Black River. All fish that were stocked into the Black River were implanted with a passive integrated transponder tag, which will aid future management efforts. In addition, 503 Lake Sturgeon were released into Mullett Lake, all of which were implanted with a coded wire tag.

The Sturgeon released into Black River and Mullet Lake reached an aver-age length of over 8 inches. Increased size at stock out can be attributed to both an improved feeding strategy developed and published by John Bauman, MDNR as well as longer residency time, as fish were held until mid-September in 2016.

Research efforts in 2016 focused on early mortality in larvae, largely attributed to early life predation. In addition, researchers continue to investigate the downstream passage of juvenile Lake Sturgeon through hydroelectric facilities. The research crew also began a pilot investigation into the effects of temperature and cortisol on eggs spawned inboth match and mismatch conditions. Smaller projects included an ongoing evaluation of sturgeon feeding rates in the hatchery, an evaluation of alternative foods on body size and survival of lake sturgeon, and the effect of aquatic macro-invertebrates on Lake Sturgeon Eggs and free embryos.