2020 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 2020 Black Lake research season began on May 5thwhen Michigan State University (MSU) and Michigan Department of Natural Resources (MDNR) researchers captured 17 adult Lake Sturgeon ascending the Upper Black River. Radio Frequency Identification (RFID) data suggests that Lake Sturgeon Adults were in the river on April 27th, 2020, however, due to complications with staffing as a result of the COVID-19 pandemic, MSU was only able to monitor remotely until 5 May 2020.

A total of 140 adult Lake Sturgeon were captured during the spawning season, of which 23 were captured for the first time (16.43%). Of the first time captures, two fish showed signs of hatchery origin. The largest single day capture was onMay 6th, where the crew sampled 42 fish. The largest fish captured this year was a 5.9-foot female that weighed 90.10 pounds. Gametes were collected from spawning Lake Sturgeon and transported to the Streamside Rearing Facility for fertilization and rearing. In total, 1,190 unique individual 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 fulfill all stocking quotas with fish captured in the wild, where possible. This year, larval drift sampling began on May 26th and continued sparsely until June 7th. Due to staffing restrictions, only 5 nights could be sampled in 2020. Researchers captured 13,919 wild dispersing larvae at Site D but were not able to rear for stocking.

Due to staffing restrictions due to COVID-19, only 100 fall fingerling sturgeon were stocked in 2020. A small number of fish retained for a graduate research project were able to be allocated to Sturgeon in the Classroom so that the program could proceed in 2020. Thanks to a partnership with the Little Traverse Bay Bands of Odawa Indians (LTBB), those fish were delivered to the LTBB Hatchery on 24 July 2020. During the fall juvenile Lake Sturgeon assessment, we captured 10 fish across 4 nights.

Researchers conducted a mark-recapture assessment across four transects from the mouth of the river to Red Bridge nightly from dusk until completion during the week of August 2nd, 2020. Two fish were recaptured across three recapture nights. Efforts to derive a population estimate for 2020 are ongoing.

Research efforts in 2020 focused on factors contributing to reproductive success; particularly those that can be quantified by data collected from Radio Frequency Identification (RFID) antennas placed throughout the Upper Black River including migratory strategy, inter-annual migratory trade-offs and sperm quality. This work resulted in a publication in the Canadian Journal of Fisheries and Aquatic Sciences.

Additionally, 2020 marked the continuation of a project evaluating the factors contributing to olfactory imprinting by age-0 Lake Sturgeon. Graduate Student Jake Kimmel raised a small number of Lake Sturgeon under differing water combinations (ground water, Black River Water) to differentiate when Age-0 Lake Sturgeon imprint on their natal water. Additionally, Jake monitored the changes in amino acid consistency in the Upper Black River as this has shown to differentiate imprinting in salmonid smolts. Analysis of that data is ongoing.

Continuing research through MSU includes: the selective properties of female lake sturgeon ovarian fluid; downstream outmigration of drifting Lake Sturgeon and the consequences for recruitment; behavioral plasticity as a function of intra-species reproductive competition and its consequences for current and future reproduction; the interaction of predatory and herbaceous macroinvertebrates, fungi, antibiotics and lake sturgeon eggs; and feeding efficiency of Lake Sturgeon in the hatchery.

Despite challenges faced due to the ongoing pandemic, MSU was able to salvage the survey work for 2020. While we captured a limited number of adults, we were still able to monitor the entire adult run using RFID. Additionally, we were able to complete the entire juvenile survey, and managed to salvage the Sturgeon in the Classroom program.