Some Facts on Aquaculture as relate to the practice of Fish Farming in the Georgian Bay Watershed

Some Facts on Aquaculture as Related to the Practice of Fish Farming in the

Georgian Bay Watershed

Locations

• The first commercial open netcage fish farm operation in Georgian Bay opened in 1982. (Sippel & Muschett, 1999)

• Since then, the number has climbed to at least nine licensed sites, most of which are located in the North Channel (Bay of Islands and McGregor Bay Association areas). (Gale, 1999)

Land-based vs. Open water Fish Farming

• Land-based aquaculture facilities (ponds, raceways, and tanks) must comply with treatment and water quality standards. Land sites have to obtain Certificates of Approval to Discharge from MOE for the treatment of wastes from the operations and for their release into water bodies so that negative impacts are minimized. (Sippel & Muschett, 1999)

• In contrast to land-based (contained) operations, the nets of cage culture operations are suspended in public waters. Open netcage aquaculture operators are issued an Aquaculture Licence by OMNR. With this licence, (along with a Land Use Permit) operators gain use of unlimited freshwater at no cost and free disposal of the wastes and byproducts of their industry. (Great Lakes Fishery Commission, 1999)

• “Presently, cages are the most harmful form of aquaculture facilities in terms of nutrient pollution and impacts on biodiversity, since they externalize to the environment many of the adverse effects of operating the facility. However, cages are not necessary to aquaculture: the fish species now raised in cages can also be raised in other types of facilities, such as man-made ponds, raceways and tanks.” (Environment Commissioner, 2001)

Impacts on Water Quality

• Much of Georgian Bay, Lake Huron, and the North Channel is a dilute, oligotrophic (naturally low in nutrients) lake which is sensitive to nutrient input. “Historic Environment Canada water quality data indicate the North Channel averaged total phosphorus of < 5 mg/L, total Kjeldahn nitrogen 0.150 mg/L and dissolved oxygen levels > 5 mg/L, one meter above bottom. (Gale, 1999)

• A prime example of the damage that can incur from cage culture operations is revealed by the now shut down LaCloche Channel site. This facility was phased out of operation by 1998, after 8 years of operation.

“MOE found that the dissolved oxygen levels were extremely low throughout the bay where the LaCloche site was located. In fact, there was absolutely no oxygen present at all in the deeper parts of the water over an extremely large area (250 ha). The water also had high phosphorous levels and algae. As a result, fish were not able to survive in the deep water of the bay and were forced to move to other areas of Lake Huron.” (Environment Commissioner 2001)

Nutrient Loading

• “Lake-based cage culture of trout in the Georgian Bay area continues to dominate other land-based production systems, accounting for 3,200 tonnes, nearly 80% of the total production.” (Moccia & Bevan, Aquastats 2001)

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Scientists have estimated that at production of this magnitude (3,000 tonnes), “This would yield an approximate loading of 15 tonnes total phosphorus, 90 tonnes nitrogen, and 500 tonnes solid waste per year. The industry predicts the production level will double in the next decade (Possible 30 tonnes phosphorus loading).” (Gale, 1999)

Nutrients as Feed

• Farmed rainbow trout are fed extruded food pellets that commonly consist of a combination of fish meal, fish oil, corn gluten meal, poultry meal, soybean meal, blood meal, feather meal, as well as other ingredients including vitamins and minerals. An artificial colourant like Astaxanthin (50ppm) is also added to achieve the same orangey-red flesh colour as wild rainbow trout. (Martin Mills, 2003)

Chemical Pollutants

• The major kinds of chemicals besides additives like vitamins and colourants, regulated for use in aquaculture are antibiotic medicinals (mixed into the feed when needed) to treat infections caused by a variety of bacterial and fungal diseases. Pesticides and disinfectants may also be used. (Environment Canada, 2001)

• “Chemical releases to the environment through routine inputs of feed and faeces containing various additives and medicinal products are likely to occur continuously at low concentrations. Chemical inputs at higher concentrations can occur during certain periods of the production cycle such as during high growth periods and equipment cleaning.” (Environment Canada, 2001)

• “Residues (of chemicals used) incorporated into sediments may persist for long periods, particularly in the anaerobic conditions often found under fish cages.” (Environment Canada, 2001)

Impact on Wild from Farm Escapes

• The common size netcage (50 ft wide X 50 ft long X 50 ft deep) is considered large enough to contain about 30,000 fish. The largest of the cage operations holds a licence for 30 cages. Other sites typically operate anywhere from 6 to 16 cages for growing fish.

• Escapes of rainbow trout raised in open net cages is inevitable and unavoidable. Escapes of large numbers are caused by nets ripping apart. This can occur due to violent storms, winter ice, boats, or poor maintenance. As many as 30,000 fish may escape from a single cage that has been damaged. Escapes of this magnitude pose threats to wild fish in that escapees compete for food and can potentially displace wild fish from native habitat and dominating spawning habitat. Escapes may carry disease organisms into the wild and may interbreed with wild species and breakdown local genetic adaptations or pose threats to aquatic biodiversity. (Midwest Fish and Wildlife Conference, 2000)

On the Use of Public Trust Resources

• Fish, wildlife, and navigable waters (including Great Lakes bottomlands) are common property of the people of the provinces and states that surround the Great Lakes. This common property right is one of the oldest public rights with roots from 13^th century English Law. Caged aquaculture operations … use Great Lakes bottomlands and aquatic biota to treat their wastes…This loss of the public’s property value from caged aquaculture wastes is a direct, but hidden, public subsidy to this industry. This is in direct contrast to land-based aquaculture facilities that are highly regulated and must use their own capital to treat their wastes prior to discharge to public trust waters…As the trustee for the public’s property, it is incumbent upon the provinces and states to be highly selective in allowing the use of caged aquaculture systems in Great Lakes waters... (Great Lakes Fishery Commission, 1999)

References

Environment Canada. Atlantic Canada. June 2001. Environmental Assessment of Freshwater Aquaculture Projects: Guidelines for consideration of Environment Canada’s Expertise.

Environment Commissioner of Ontario, 2001. Annual Report, Having Regard. 2000-2001 Annual Report.

Gale,P. 1999. Ontario Ministry of Environment. Water Quality Impacts from Aquaculture Cage Operations in the LaCloche /North Channel of Lake Huron in Addressing Concerns for Water Quality Impacts from Large-Scale Great Lakes Aquaculture. Great Lakes Fishery Commission, August 1999.

Great Lakes Fisheries Commission. August 1999. Synthesis of Roundtable Discussion and key Findings in Addressing Concerns for Water Quality Impacts from Large-Scale Great Lakes Aquaculture.

Martin Mills Inc. (information sheet as received in 2003). Modern Fish Feed Ingredients Ensure Nutritious & Safe Aquaculture Products. Elmira, Canada.

Midwest Fish and Wildlife Conference. December 2000. Regional Aquaculture and Concepts of Environmental Sustainability: Proceedings paper for Environmental Strategies in Aquaculture Symposium.

Moccia, R. and D. Bevan, February 2003. Aquastats 2001.

Sippel A. and M. Muschett. 1999. Ontario Ministry of Natural Resources. Aquaculture – Experiences and Lessons: Ontario Ministry of Natural Resources in Addressing Concerns for Water Quality Impacts from Large-Scale Great Lakes Aquaculture. Great Lakes Fishery Commission, August 1999.