Aquaculture's pressure on forage fisheries remains hotly contested. This article reviews trends in fishmeal and fish oil use in industrial aquafeeds, showing reduced inclusion rates but greater total use associated with increased aquaculture production and demand for fish high in long-chain omega-3 oils. The ratio of wild fisheries inputs to farmed fish output has fallen to 0.63 for the aquaculture sector as a whole but remains as high as 5.0 for Atlantic salmon. Various plant- and animal-based alternatives are now used or available for industrial aquafeeds, depending on relative prices and consumer acceptance, and the outlook for single-cell organisms to replace fish oil is promising. With appropriate economic and regulatory incentives, the transition toward alternative feedstuffs could accelerate, paving the way for a consensus that aquaculture is aiding the ocean, not depleting it.

No abstract

No abstract

No abstract

Signi®cant efforts should be devoted to reducing waste outputs from aquaculture operations in order to lower the environmental impacts of aquaculture in many parts of the world. Since most aquaculture wastes are ultimately from dietary origin, reduction of waste outputs should ®rst be through improvements of diet formulation and feeding strategies. The ®rst step in the production of feeds producing less solid waste is to eliminate poorly digestible ingredients (such as whole grain or grain byproducts used as binders and ®llers in the feed formulae) and to use highly digestible ingredients with good binding properties. Further reduction of solid waste can then be achieved through careful selection of the ingredients to improve apparent digestibility and the nutrient balance of the feed. Nitrogen waste outputs can be reduced through the reduction of the digestible protein to digestible energy (DP/DE) ratio of the diet. Phosphorus waste outputs can be reduced through careful selection of the ingredients and optimization of the digestible phosphorus content of the diet to meet the requirement of the ®sh but avoid greatly exceeding this required level. Finally, feeding practices that minimize feed wastage should be adopted since feed wastage can have a very signi®cant impact on waste outputs from ®sh culture operations.

No abstract

No abstract

No abstract