Aquaculture  - Biotechnology topics

Each fish within a species has its own unique combination of genes. The genetic diversity of a species is measured as the variety of genetic traits found within a given species. The greater the diversity, the greater the species’ ability to adapt to environmental changes and other survival tolerance extremes (stresses). Like most organisms, when fish lose too many individuals of their species, for example, through loss of habitat or overfishing, the populations become more genetically uniform (‘inbred’) and more susceptible to disease or other health problems that could compromise species survival (c.f., the cheetah syndrome). The long-term environmental and economic sustainability of Canada’s wild, as well as cultured aquatic resources, therefore, depends on genetic diversity.

What’s the issue?

We know little about the genetic structure of even our most valuable fisheries species and, thus, lack key information essential to optimum management of both wild and farmed stocks.

Fisheries and Oceans Canada (DFO) is helping to address this issue by forming a permanent partnership with Dalhousie University to study the genetic biodiversity of marine organisms. The first research project under the partnership is mapping out the genetic structure of three of the most valuable commercial marine species in Atlantic Canada – lobster, herring and haddock – using DNA-probe technology.

The research plan

DNA probes are tools that identify sections of DNA that correspond to the pattern of the probe. When such DNA sequences are present in a sample, a chemical reaction is triggered that causes the probe to "light up". More than 50 DNA probes already exist for lobster and these are being used to see if the genetic information they uncover is useful for the determining the genetic diversity of lobster stocks in Atlantic Canada. Researchers will use any probes that show promise for genetic assessment of lobster spawning populations to define stock boundaries and interactions in the southern Gulf of St. Lawrence and southwest Nova Scotia.

Researchers are also developing new DNA probes for herring, to map out the genetic structure of herring populations in the Gulf of St. Lawrence and Georges Bank. Similar work is being conducted for haddock, but this species needs more probes than herring because the probes will be used to assess the genetic diversity of three haddock populations (to help commercial fishery management), as well as to select haddock broodstock for aquaculture. For aquaculture, the goal is to develop broodstock that are defined genetically, show genetic diversity between individuals, and include desirable genetic traits.

Benefits of this research

This research will have positive impacts in three key areas. It will:

help protect biodiversity within these three species;
improve the efficiency of fisheries and aquaculture management; and,
help ensure environmentally and economically sustainable use of these resources for both commercial fisheries and aquaculture purposes.