Aquaculture  - Biotechnology topics

Molecular biotechnology is opening up new frontiers in many fields. In fisheries, molecular biotechnology has the potential to help preserve the biodiversity of threatened fishery resources, increase aquaculture production of fish and shellfish for food, and reduce harvest pressure on wild stocks.

While these new molecular technologies offer benefits for the use and conservation of our fishery resources, they have also raised concern over potential risks that need to be evaluated. Genetically modified aquatic organisms, such as transgenic salmon, are one example.

What is the issue?

Transgenic organisms have genes inserted into their genetic make-up that may come from the same organism (but are modified to enhance a trait the organism would not normally posses), or be from another, unrelated, organism. Salmon are currently being studied for transgenic enhancement of certain production traits, such as growth rate or cold tolerance. However, since any organism developed for aquaculture is destined for introduction into Canada’s food supply, they need intensive study to ensure they pose no risks to human health. In addition, production using open-water culture systems means they also need to be assessed for any potential threat to wild salmon stocks or other aquatic species and their habitats.

Scientists at Fisheries and Oceans Canada (DFO) have embarked on non-commercial studies of transgenic technology, using coho salmon (Oncorhynchus kisutch) genetically modified to enhance growth as a model species. These salmon allow scientists to evaluate their performance under controlled laboratory settings. DFO researchers, in collaboration with Health Canada, the Canadian Food Inspection Agency, Canadian and international university researchers, are investigating food safety and human health issues, as well as the potential for transgenic salmon to interact negatively with wild salmon. The results from these studies will help in decision-making, if transgenic salmon are proposed for introduction into the food supply. The results will also contribute to formulation of new regulations, or regulatory changes, that may be required under the Fisheries Act before transgenic salmon can enter commercial production. (Current regulatory oversight is provided under the Canadian Environmental Protection Act).

The research plan

The research team will examine the food safety and human health aspects of growth-enhanced transgenic salmon (salmon with a growth hormone gene construct inserted into their genetic makeup), including nutritional quality and hormone levels. The scientists will also study the stability of the inserted genes (changes in activity levels in the transgenic salmon or its descendents), as well as, activity of the growth hormone.

Under contained laboratory conditions, researchers will evaluate growth rates, nutritional requirements, disease susceptibility and quality of meat, under various culture conditions.

They will also investigate possible impacts of interactions with wild salmon, to evaluate any risk that escapee transgenic salmon may pose. This will include feeding behaviour and aggressiveness of transgenic salmon, as well as swimming ability, capacity to reproduce and tolerance of physiological stresses, such as, confinement and changes in temperature and oxygen levels.

Another important, and related, area of research is how to limit the reproductive capability of transgenic salmon so that, if they escape, they cannot affect the genetic makeup of wild populations. Researchers will develop and evaluate reproductive ‘containment measures’, including triploidy (salmon with an extra set of chromosomes which makes them incapable of producing viable eggs or sperm) and sex-specific genetic traits that inhibit reproduction (see ‘Biotechnology to help Protect Wild Salmon Stocks – The Triploid Approach’ and ‘Biotechnology to help Protect British Columbia’s Wild Salmon Stocks – The All-Female Approach’).

Benefits of this research

This research will provide the data needed to clarify the benefits and risks of using transgenic organisms in the food supply. Specifically, it will:

provide objective, scientific information on transgenic salmon, for scrutiny by the scientific community and the public;
help identify any risks associated with introducing transgenic aquatic organisms into the Canadian food supply, so these can be avoided/minimised;
assess the strengths and weaknesses of current regulations and provide information to improve regulatory controls to prevent environmental impacts of transgenic fish; and,
help build scientific capacity within government to accurately evaluate risks from genetically modified and transgenic foods.