AN OVERVIEW OF BINATIONAL EFFORTS TO USE CULTURE AND STOCKING TO RESTORE AN EXTIRPATED SPECIES Coregonus hoyi TO LAKE ONTARIO

Kevin K. Loftus*, Tim D. Drew, Ryan W. Zheng, Jennifer L. Smith, Trevor E. Pitcher, Timothy B. Johnson and Chris C. Wilson
 
Fish Culture Section, Fish and Wildlife Services Branch
Ministry of Natural Resources and Forestry
P.O. Box 7000, 300 Water Street, Peterborough, ON, K9J 3C7
kevin.loftus@ontario.ca

Bloater, Coregonus hoyi, is one of four species of deepwater cisco that was extirpated from Lake Ontario in the last century. Historically, these four species formed the backbone of the lake's deep water prey fish community. A bi-national team consisting of the Ontario Ministry of Natural Resources and Forestry (OMNRF), the New York State Department of Environmental Conservation (NYSDEC), the U.S. Fish and Wildlife Service (USFWS), the U.S. Geological Survey and the Great Lakes Fishery Commission, believes that conditions in the lake have evolved to the point that re-establishment of the species is now possible.  Restoration efforts are being guided by the following strategies:  develop a reliable source of gametes, develop husbandry practices, increase culture capacity, assess and optimize stocking effectiveness, understand ecological role, and increase public awareness. This presentation provides an overview of progress on several OMNRF-led strategies.   

The OMNRF Fish Culture Section staff agreed to co-lead efforts to develop husbandry practices because it had 30 years of experience culturing Lake Whitefish, C. clupeaformis, a related species.  Since it first began culturing Bloater in 2011, much has been learned, and survival rates during both the incubation and early rearing phases have increased dramatically.  To date, the effects of diet and temperature on growth and survival have been examined.

In 2011, OMNRF Fish Culture Section staff also began developing a captive broodstock. The decision to do so stemmed from the challenges being experienced by the USFWS collecting sufficient numbers of gametes from wild populations in Lake Michigan during the winter months. To date, two year classes of broodstock have matured and produced viable gametes.  Unfortunately, fewer fish matured than expected and a lack of synchrony between the sexes limited the number of fertilized eggs collected. Staff have partnered with the University of Windsor to investigate the potential of hormone induction using LHRHa to stimulate spawning as well as cryopreservation to preserve sperm until females reach peak spawning.  Preliminary results from hormone injection show promise.

In 2014, OMNRF science staff, in collaboration with NYSDEC staff and others, initiated the use of acoustic biotelemetry to describe post-release movement, behaviour, and survival of stocked Bloater.  Initial results are encouraging.