Aquaculture Feeds and Nutrition
Fish, both farmed and wild, require a balanced mix of essential nutrients, amino acids, fatty acids and energy. Traditionally, fish feeds have contained a high percentage of fishmeal and fish oil because the balance of nutrients most closely resemble the requirements of fish. However, partial or total replacement of fishmeal and fish oil in feeds is becoming the norm. Feeds eliminating these ingredients have been used experimentally to feed farmed Atlantic Salmon, Rainbow Trout, Red Sea Bream, Grouper, White Sea Bass, and Cobia. Fish in these studies show similar growth and survival to those fed on feeds containing fish meal and fish oil.
Farmed fish are more efficient protein converters than terrestrial livestock. This means that for every pound of feed you feed to farmed fish, you get out more edible protein than you do with animals such as cows, pigs or chickens. For example, some studies have shown that 100 kg of dry feed yields 65 g of boneless salmon fillet, compared to only 20 kg of edible product from poultry or 12 kg from pork.
Fishmeal & Fish Oil
The use of fishmeal and fish oil in aquaculture feeds has been highlighted as a major sustainability issue and limitation to the growth of finfish aquaculture. About 70% of fishmeal and oil comes from fisheries targeted at small, wild pelagic fish, such as sardine, anchovy and menhaden. The remainder comes from processing fish wastes.
Over the past several decades, the world supply of fishmeal and oil coming from these fisheries has been constant. However, these stocks are more and more being used for direct human consumption. Increased demand with fixed supply has caused prices in fishmeal and oil to increase dramatically over the last decade, spurring the development of alternative aquaculture feeds. The amount of fishmeal and oil used in aquaculture is decreasing, and is projected to continue to decrease.