Great Lakes Fishery Commission

Updated 2024-12-13 14:19:58

Lake Huron -> 5.0 Coregonine (Lake Whitefish and Cisco) -> Cisco Rehabilitation

5.1.2. Recapture rate of hatchery-reared Cisco

Historically, Cisco (Coregonus artedi) was one of the most abundant pelagic fishes, found “out of virtually every port on Lake Huron, in the North Channel, and Georgian Bay” (George, 2019). Cisco remains relatively common in northern Lake Huron including Georgian Bay and the North Channel, but is rare in Michigan waters of the central and southern main basin (Cotrill et al., 2020; Eshenroder et al. 2021a, b). Therefore, several fishery management agencies have undertaken efforts to re-introduce coregonine diversity. These efforts helped lead to development of a science-based framework to restore coregonines that was universally endorsed by fishery managers representing eight U.S. states, four U.S. tribal organizations, and the province of ON, Canada, in May 2018.

Since major declines in abundance of Cisco populations in the 1950s, Cisco is no longer found in Saginaw Bay where it once supported the largest fishery in the lake (Baldwin et al. 2009). Successful reintroduction of Cisco in Saginaw Bay may be critical to the overall recovery of Cisco in the main basin and provide multiple benefits: (1) diversifying the fish community and promoting sustainability of the food web, (2) establishing a larger-bodied prey fish that will reconnect the broken linkage between the nearshore and offshore energy pathways, (3) providing a prey buffer for other fishes such as yellow perch (Perca flavescens), and (4) potentially supporting its own future fisheries (Lake Huron Technical Committee 2023). As a result, the Lake Huron Committee initiated a multi-agency, Saginaw Bay reintroduction effort in 2018 that has resulted in the annual stocking of one million Cisco reared by USFWS (Figure 1), using northern Lake Huron populations as the gamete source (Lake Huron Technical Committee 2023). The first gamete collection of Cisco was taken in 2016 from the Le Cheneaux Islands and Drummond Island broodstock population in northern Lake Huron. Those gametes were used to develop 4 lines of brood stock which then were used to produce progeny that were first stocked into Saginaw Bay in 2018 (Figure 1). Hatchery-reared Cisco are released into Saginaw Bay in the spring (5-month-old individuals) and then again in the fall (8-month-old individuals). Each release group receives a unique oxytetracycline mark to determine if survival depends on age at release (Supplementary Figure). Objectives of the Saginaw Bay Cisco restoration study are to assess the extent to which cultured Cisco survive to maturity, determine if cultured Cisco will return to Saginaw Bay to spawn, and evaluate if they are able to successfully reproduce. Adults were hypothesized to begin returning to Saginaw Bay in 2022 or 2023, and in December 2022, 46 marked adults were recaptured in Saginaw Bay. These initial results suggest cultured Cisco can survive and spawn in Saginaw Bay, however it is yet to be determined if they can produce viable recruits.

Number of cisco fingerlings stocked into Saginaw Bay, Lake Huron, by season (spring and fall) and year. In 2018, stocking occurred only during the fall.

Number of hatchery-reared Cisco recaptured in Saginaw Bay, Lake Huron, by year.