State of the knowledge of culturing native fishes in the Great Lakes: Applying an eco-genetic model to inform the risks and identify key knowledge gaps

PARR-2017-CA-08

Description

Proposals for culturing native freshwater fish species can pose risks associated with the potential of genetic interactions with wild conspecifics (i.e., belonging to the same species). Ongoing low-levels of escaped fish from cages is likely, and larger escape events have occurred in the past, both of which could result in interactions between farmed fish with wild stocks. This project examined the ecological and genetic risks of Yellow Perch, Walleye and Lake Whitefish escapees on conspecific wild populations in Lake Huron by conducting a directed literature review and data assessment to summarize the state of knowledge.

The state of knowledge was evaluated to identify the extent to which defensible information exists on culturing these fish species, and to identify existing knowledge gaps. The literature review included key processes, such as rates of inheritance, growth and maturation, important to determining ecological and genetic impacts. Results from the project may help to inform management decision making, policy development and identify data gaps for future priority research.

Findings

Our synthesis revealed few studies to date. When available, information on gadoids and cyprinids was used. Escaped farmed fish had behavioural deficiencies in the wild and their expected survival is low. However, there is evidence that escaped farmed fish exploit the same resources as wild species and can interbreed resulting in hybrid salmon species which could lead to introgression (i.e., transfer of genetic information).

Disease transfer from wild to farmed fish is much higher than farmed to wild. Some of the diseases contracted by farmed salmonids have also been noted in these three species of interest. Feed conversion ratios (FCRs) for Walleye, Yellow Perch and Lake Whitefish tended to vary more than salmonids. Limited information was available on the optimal dietary requirements, proper feeding regimes and other husbandry practices that are associated with higher waste outputs.

Program Name

Program for Aquaculture Regulatory Research (PARR)

Years

2017 to 2018

Principal investigator

Thomas Pratt
Research scientist, Fisheries and Oceans Canada, Great Lakes Laboratory for Fisheries and Aquatic Science, Great Lakes Forestry Centre, Central and Arctic Region
Email: Thomas.Pratt@dfo-mpo.gc.ca