Facts about fish

In term of efficiency, fish in aquaculture systems are very efficient converters of feed into protein – in fact far more efficient than most terrestrial livestock system. For instance, poultry converts about 18 % of their consumed food and pigs about 13 %, as compared with 30 % in the case of fish. Production of 1 kg of beef protein requires 61.1 kg of grain, production of 1 kg of pork protein requires 38 kg of grain, while fish only requires 13.5 kg. Most of this difference comes from two biological characteristics of fish which give them great advantages over land-based livestock in growth performance. Fish are poikilotherms and therefore do not expend energy maintaining a constant body temperature and finfish are physically supported by the aquatic medium, fewer resources are used on bony skeletal tissues, and a larger part of the food they eat is effectively allocated to body growth. In terms of carbon footprint, aquatic animal production systems have a lower carbon footprint per kilogram of output compared with other terrestrial animal production systems. As a consequence, nitrogen and phosphorous emissions (kg of nitrogen and phosphorus produced per tonne of protein produced) from aquaculture systems are much lower than those in beef and pork production systems and slightly higher than that of poultry.