Saskatchewan Aquaculture

Although aquaculture is just beginning to gain popularity in Saskatchewan, this province is nonetheless the third largest producer of rainbow trout in Canada. That's largely due to the Wild West Steelhead (formerly CanGro Fish Farm) at Lucky Lake, SK. This farm, produces approximately two million lbs. of trout annually. In the next year, Saskatchewan is likely to pass Quebec in rainbow trout production, and become the second largest producer in the country.

In Saskatchewan, biotechnology is applied to research new feed sources and to improve the composition of the feed. This is where much of Saskatchewan's aquaculture research is focused.

Right now the most common protein source for many fish diets is fish meal. Fish meal, a by-product of fish processing, is used because of its high quality and high protein content. However, it has some disadvantages. One disadvantage for fish producers is that it is expensive. So any cheaper alternative protein source would be welcomed.

Another concern regarding fish meal is the stability of supply. Fish meal comes from the by-products of wild fish, but world fish stocks are declining. At the same time, fish farming is on the rise, and demand for fish meal is increasing. Given these factors, it's unlikely there will be enough wild fish to meet the increasing demand for fish meal.

The use of fish meal in aquaculture causes other environmental concerns, as well. It contains levels of phosphorus far beyond the requirement for optimal growth in fish. The excess phosphorus goes into the water, causing problems such as eutrophication or excess algae growth.

As a result of these concerns with fish meal, researchers are using biotechnology to produce alternative plant-based protein sources. Plant protein has the potential to address the problem of phosphorus pollution, since plants do not contain such high phosphorus levels. As well, the use of plant protein in aquaculture would help take the pressure off wild fish stocks.

Research in this province is focusing on the investigation of local crops as new sources for fish feed protein. Some of the potential fish meal replacements include distillers by-products, pulse crops and canola. Wheat, canola and canola oil are already being used to some extent in feed for aquaculture. Fish are very efficient in their growth, requiring much less energy than other animals. In the lab, researchers are able to give fingerling fish 700 g of feed and obtain 1,000 g of growth. That's because most of the growth is muscle, which is mainly water. Because fish have such low energy needs, they can use high levels of dietary protein, often up to 40 percent to 50 percent of the diet. For Prairie crops to be used as the main protein source for fish, they must be processed into a concentrate. Biotechnology is often used in this processing. Plant protein also requires processing because plants contain what are called anti-nutritional compounds as a defence mechanism. These compounds must be destroyed during processing, or they could harm the fish.

Researchers are also trying to deal with these anti-nutritional factors by producing feed enzymes to counteract them. Phytase is one example. This enzyme would help fish make the best use of the phosphorous available in a plant-protein based feed.

Fish Futures;

With the worldwide growth in aquaculture , and increasing interest here at home, there is likely to be considerable demand for the products of Saskatchewan aquaculture research. New plant-based protein sources and feed enzymes will help to make aquaculture an environmentally sound and sustainable farming operation. Special thanks to Paul Adelizi, Feed Scientist, Saskatchewan Wheat Pool