The Use of Fish Meal and Fish Oil in Salmon Feed

In the “Effect of aquaculture on world fish supplies” by Naylor et al., published in Nature (volume 405, June 200), the growth of the salmon aquaculture industry is criticized for contributing to the depletion of wild fish stocks. The article states that because of their dependence on wild-caught fish, shrimp and salmon aquaculture deplete fisheries resources rather than supplement demand.

Carnivores versus herbivores

A distinction should be made between carnivorous species including salmon and shrimp and herbivorous species including tilapia and carp. The carnivores require both fishmeal and fish oil in order to fulfill their nutritional requirements. Herbivorous species, on the other hand, can utilize vegetable sources for protein.

Research

Through research and experimentation, the salmon aquaculture industry has significantly reduced the amount of fish meal and fish oil required in the salmon’s diet. According to Hole 2000, researchers have:

• Further defined the nutritional requirements of salmon;
• Increased the digestion rate of the feed;
• Reduced the overall feed conversion ration (FCR) or the amount of food required to produce a particular amount of fish;
• Investigated vegetable alternatives to fish meal and fish oil (if necessary, up to 65% of fish oil can be replaced with vegetable oil);
• Minimized overfeeding through the use of underwater cameras; and
• Evaluated the potential of using byproducts of fish processing for sources of fish meal and fish oil.

Salmon

Our fish farms estimate that 2.98 lb of wild fish is required to produce 2.20 lb of farmed salmon.

In addition, salmon are far more efficient at using energy and protein resources than terrestrial livestock.

Fish meal and fish oil

Fish meal and fish oil are primarily produced from small pelagic fish such as anchovy, mackerel, jack mackerel and sardine. These fish are predominantly fast-growing and short-lived and are rarely used for human consumption. On the other hand, the majority of fish listed as over-fished by the FAO’s (1998) report “The state of world fisheries and aquaculture” are fished for human consumption and are characterized as long-lived and slow-growing.

The majority of small pelagic fish utilized for fish meal and fish oil are caught off the coast of Peru and Chile. Both countries actively manage their fisheries, maintain close contact with international organizations and conduct their own fisheries research. Currently 31% of the world supply of fish meal and 40% of the world supply of fish oil are utilized for aquaculture. The remaining supply is utilized for poultry and pork feed.

The supply of commercially valuable fish from aquaculture has dramatically expanded during the past 15 years, while the catches of small pelagic fish have remained more or less constant. Furthermore, the price of fish meal and fish oil has remained relatively stable over the same period.

Should further expansion of aquaculture raise demand for fish meal, it is far more likely that this will be achieved through a shift of markets, from pig and poultry to fish, rather than through an increase in either the pelagic catch of an increase in the proportion of the total catch used for these products. Fish oil is a different story. An increase in demand is most likely going to be met through the addition of vegetable oils.

Summary

Feed is the largest production cost for commercial aquaculture; therefore, our farms have a strong incentive to produce feed as efficiently as possible. Finally, our farms endorse the view that the long-term growth of the aquaculture industry cannot rely solely on the wild catch of fish.

The information presented in the above fact sheet was sourced from “Farming has little effect on stocks” by Dr. Reid Hole, Director of Technology and Development, Nutreco, published in Fish Farming International (September 2000).