Powell, K. , 2005. Fish farming, Eat your Veg, Nature, 426, 378-379. The article that I chose to review discussed the possibility of maintaining and sustaining aquaculture by changing the diets of the farmed fish.
The idea of carnivorous fish turning into vegetarians would help for future sustentation of aquaculture. There were pros and cons to either side of vegetarianism and the maintaining of carnivores. There are issues that would require research and analysis to which the author points out to the reader. Aquaculture has increased by 5% over the past 10 years. The wild stock of fish that is caught to feed the fish farms has numbered 11 million tons, which is 12 % of the total fish hauled from the sea each year. Carp and tilapia are the most farmed fish in the industry that already are consisting of a vegetarian type diet.
Salmon and trout are the next largest farmed fish. The difference is that the salmon and trout are carnivores. The author reports that the carnivorous fish are more expensive to cultivate and more resources are needed to maintain these types of farmed fish. Most farmed fish are fed on a diet that consists greatly of fish oil and fishmeal. Fishmeal is made from a protein rich powder of ground up cheap fish as a source of nutrients and proteins. The problem with using these within the farm diet is that the demand for the fish oil will overpower the supply as aquaculture expands and booms.
The Term Paper on Fish Farming
... to maintain optimal water quality. Through this system, many of the environmental drawbacks of aquaculture are minimized including escaped fish, ... wild salmon must “run a gauntlet” of large fish farms located off-shore near river outlets before making their ... have not successfully been incorporated into the diets of carnivores. Secondly, farmed fish are kept in concentrations never seen in ...
The author states that the “demand will outstrip supply of oil by 2010.” (Powell).
Feed companies which supply the fish farms with fishmeal and fish oil as a staple to the diet of the carnivorous fish will seek different sources of protein. This protein could possibly come from larger fish such as mackerel, herring, and blue whiting. If this happens it would put more pressure on the natural stock already being harvested for other purposes.
Some companies are traveling to the Antarctic to collect krill, which has repercussions for the bottom of the food chain in that the ocean itself is a primordial web of life. The author boosts that the fish will be able to eat Soya beans, corn, rapeseed, sunflower seeds, flaxseeds, and wheat gluten if converted to a vegetarian diet. The author also reports that some salmon farms already use these foods as staples in their fish farm diets. The farms can only use these ingredients to account for only half of the fish diet. If more than half is substituted in the daily diet then serious digestion problems can occur.
The entire diet would have to be supplemented with amino acids and the fat content would have to be altered. The problem with amino acid supplements is that it is not cost effective. The author reports that within the next 5-10 years that the vegetarian feed would be realistic and affordable. If the industry is successful in converting a carnivorous fish into a vegetarian fish then less pressure would be placed upon the natural fish population, less pollution from phosphorous and nitrogen, reduced cost of fish, and reduced world hunger. The author stated that if the world had more fish at a cheaper rate the more nations would be able to feed their hungry..
