POST-STOCKING BEHAVIOUR, HABITAT USE, AND SURVIVAL OF HATCHERY-REARED NATIVE FISHES USING ACOUSTIC TELEMETRY
Until the mid-1950’s, a diverse assemblage of deepwater ciscoes including bloater (Coregonus hoyi) inhabited Lake Ontario. Currently, only the shallow-water form of Cisco (C. artedi) remains. The Lake Ontario Committee has established a plan to reestablish a self-sustaining deepwater cisco population within 25 years. The work is supported by the Lake Ontario FCOs and guided by the Strategies for the Reestablishment of Native Deepwater Ciscoes in Lake Ontario. As part of this initiative, fertilized Lake Michigan bloater eggs have been collected by the USFWS, raised to juvenile stages in New York and Ontario, and stocked in small numbers (16-35 thousand/year). With improvements to wild egg collections (1.95 million fertilized eggs in 2016) and significant progress in brood stock development, the plan to stock 500,000 juveniles per year may soon be possible. The issue is that we do not know what will happen to the stocked fish after introduction, a problem for all stocked fish. Do hatchery fish survive in the wild and does survival change through time? Is predation a significant component of mortality and does it vary seasonally? Do stocked bloater quickly disperse or stay close to their stocking site? Do they school closely together and move as a group? What factors influence their seasonal habitat use? Answering these questions is the focus of this proposal and the findings can be applied to develop more effective monitoring of stocked fish, identify survival bottlenecks and optimize culture and stocking strategies. The methodology, acoustic telemetry, will pave the way for development of comparative stocking and culture initiatives (other life-stages, seasons, locations, culture conditions) to inform and improve bloater restoration outcomes that could potentially be applied to other species (e.g., cisco, salmonids) and issues in the Great Lakes (e.g. understanding post-stocking survival , habitat associations and protection, improved monitoring).