Supporting evaluation components of the Lake Huron Technical Committee’s Cisco reintroduction study for FY23

Kevin McDonnell (USFWS, kevin_mcdonnell@fws.gov), Amanda Ackiss (USGS), Jose Bonilla-Gomez (USFWS), Cory Brant (USGS), Dave Fielder (MIDNR), Todd Hayden (USGS), Andrew Honsey (USGS), Darryl Hondorp (USGS), Tim O’Brien (USGS), Jason Smith (Sault Ste Marie Tribe of Chippewa Indians)

Cisco (Coregonus artedi) are functionally absent from the western main basin of Lake Huron and as such restoring cisco “to a significant level” (DesJardine 1995) remains an unmet objective for Lake Huron management agencies (Liskauskas et al. 2007). In 2007 the Lake Huron Technical Committee (LHTC) developed a recovery guide for cisco in Lake Huron for the Lake Huron Committee (LHC) of the Great Lakes Fisheries Commission (LHTC 2007; Liskauskas et al. 2007). The GLFC recovery guide identified cisco as an ideal candidate for reintroduction in the Main Basin of Lake Huron to promote a native, thiaminase-free, pelagic prey species that is capable of efficiently transferring energy to pelagic piscivores while providing a prey buffer for nearshore species. The LHC formally adopted a proposal in 2015 to evaluate if cultured cisco would be able to reestablish a self-sustaining population in Saginaw Bay, Lake Huron. Saginaw Bay was historically important for cisco spawning (Goodyear et al. 1982) and once supported the largest fishery in Lake Huron (Berst and Spangler 1973; Baldwin et al. 2009). To evaluate restoration strategies in this area, the LHC requested Region 3 National Fish Hatchery System produce and stock 1 million (± 20%) cisco fingerlings annually for ten years into Saginaw Bay. Fingerling age-0 cisco have been stocked in Saginaw Bay annually, beginning in 2018, and spring age-0 and fall age-0 fingerlings will be stocked annually through 2027. Early life-history monitoring, assessment of post-stocking survival, and spawning monitoring have all been identified as key elements of the stocking program evaluation. Post stocking evaluations commenced in 2019 and have continued through 2022. In 2021 the first recaptures of a juvenile and adult hatchery origin cisco were documented in Saginaw Bay. All these fish were collected near the onshore stocking location (approx. 4km north of Point Lookout, Saginaw Bay) during a spring juvenile gillnet survey (n=1) and the fall spawning gillnet survey (n=3). Preliminary data from the 2022 juvenile gillnet survey have shown an increase in catch rates of hatchery-reared cisco compared to the 2021 survey (2021 = 0.0002 fish/ft; 2022 = 0.0014 fish/ft) and we anticipate this trend to continue as previously stocked fish grow to be more vulnerable to our sampling gear. Additional monitoring of larval production, juvenile survival and adult spawning remains critical to effectively evaluate how successful the restoration efforts have been and to provide insights that may improve future restoration strategies. We are requesting funds to build off our previous work and to continue the cisco monitoring and evaluation in Saginaw Bay for FY23. It currently remains unknown to what extent now hatchery cisco will home to their original stocking site during spawning, how much predation pressure newly stocked Cisco experience immediately, how well juvenile hatchery cisco are surviving and if any successful Cisco reproduction is occurring in Saginaw Bay. Additional funds will allow us to investigate these questions directly in FY23. Alpena Fish and Wildlife Conservation Office (FWCO) will continue to act as the lead agency for these elements with support from other state, federal, and tribal partners.