Supporting evaluation components of the Lake Huron Technical Committee’s Cisco reintroduction study: a multi-agency effort to promote Cisco recovery in the western main basin of Lake Huron (FY20)

Continue to collect baseline information of larval coregonine community validated with genetic species identification:

Sampling of the Saginaw Bay larval coregonine community was completed during the spring of 2021 using pelagic ichthyoplankton tows, beach seines, and small mesh bottom trawls. Ichthyoplankton tows were done across 40 randomly selected, depth stratified sites that were sampled weekly for three weeks from March 29 - April 16th 2021. Beach seine and bottom trawls occurred weekly near 4 sites from April 19th to May 14th 2021. Bottom trawls surveys were paired with beach seine sample at each site and were completed within 24 hours of one another. Coregonids sampled from all surveys are currently being worked up and identified to species, when possible, and will also be processed for genetic confirmation.

Assess post-stocking survival, growth, and maturity of cultured Cisco:

We were unable to perform acoustic surveys in Saginaw Bay in 2020 or 2021 due to covid protocols and unforeseen staff turnover. In the spring of 2021 key personnel (C. Olds) departed the USFWS Alpena FWCO and we no longer had the resources/expertise to conduct these surveys. This survey will be scheduled for fall of 2022 after new personnel are trained in the hydroacoustic set up on the M/V Spencer F. Baird.

Assess reproduction by cultured cisco:

This objective was addressed using the same sampling identified in objective 1. The fall of 2020 was the first year that the first year class of stocked cisco (2017 yearclass) may have reached maturity (age 3). Thus, 2021 represented the first year that wild origin cisco larvae may be available to capture, assuming the 2017 year class survived and successfully spawned in Saginaw Bay. Our early life history sampling that was done in 2021 will provide evidence if these fish were able to successfully produce larvae. Additionally, in the fall of 2021 we implemented a spawning gill net survey to sample spawning adults for the first time in Saginaw Bay. Unfortunately, due to weather and unusually warm water temps we were only able to sample for 2 nights in October of 2021. Overnight gill nets were set on rocky habitat adjacent to the shore stocking location at the end of Bessinger Road just north of Point Lookout. Despite a limited initial effort, a total of 3 hatchery origin (OTC confirmed) mature male cisco were sampled.