Aquaculture  - Biotechnology topics

In order to reduce their dependence on salmon resources, many fishers and aquaculture businesses on Canada’s west coast are increasing their exploitation of alternative species, such as, geoduck (pronounced "gooey duck") clams (Panope abrupta), red sea urchins (Strongylocentrotus franciscanus) and Dungeness crab (Cancer magister).

Dungeness crab is a familiar item on West Coast seafood menus and the most important crab species harvested in British Columbia. Red sea urchins are fished for their roe (gonads) which are exported, primarily to Japan. Geoducks are huge clams that can live for 140 years or more (although commercial size can be reached in 3-5 years), attain up to 20 lbs. in weight, and are exported mainly to Asian markets.

What is the issue?

All three shellfish species have biological characteristics that make them vulnerable to over-exploitation. For example, they grow slowly, cannot migrate to avoid environmental disturbance and have irregular recruitment (the replenishment of the population with juveniles). Therefore, it is important to carefully manage these stocks – both wild and farmed – to maximize conservation and maintain the genetic biodiversity they need to survive (see ‘Marine Biotechnology Partnership to Help Preserve Biodiversity of Key Marine Species’).

Good management requires knowledge of the population structure of these species, that is, the distinct groups of interbreeding individuals that make up a distinct population. In the past, evaluating population structure was a long, expensive process done only for the most commercially important species. Today, new biotechnology tools can help. DFO researchers are studying how these techniques can be used to rapidly and inexpensively evaluate the genetic population structure of these shellfish species.

The research plan

In this three-year project, DFO researchers will develop biotechnological techniques to survey Dungeness crab populations. (Similar techniques for red sea urchins and geoduck clams have already been developed with financial support from industry). Researchers will use these tools to assess the genetic variations in each of the three species of shellfish collected from several locations along the coast of BC. The results will help determine the number of mature adults, their geographic distributions, and map out the boundaries between separate wild populations.

The second phase of this research project is aimed at developing broodstock of each species for use in commercial aquaculture, or for potential wild stock enhancement projects. Researchers will screen individuals that show good culture traits (fast growth, quality meats and gonad development), to ensure that a genetically diverse broodstock is selected for hatchery breeding programs, i.e., the genetic diversity of the broodstock used for aquaculture is as close as possible to the diversity found in the wild population.

This genetic information will also allow selective breeding to emphasize or minimize certain characteristics while avoiding inbreeding. It could also be used to select parents with rare markings that could be used as a genetic "tag" to identify them in the wild or in the marketplace. And finally, genetic data could also be used to identify shellfish that have been harvested illegally from protected or closed stocks.

Benefits of the research

In addition to increasing knowledge on the genetic population structure of geoducks, red sea urchins and Dungeness crabs, this work should help:

improve DFO’s ability to manage and conserve these species in the wild as sustainable aquatic resources;
provide the tools necessary to protect the biodiversity of wild stocks of these species; and,
support biologically and economically sustainable development of aquaculture of these species, through improved broodstock management strategies.