Aquaculture technology has provided a means of augmenting supply of natural fish from oceans and fresh water bodies and thousands of farms that produce different species of fish are able to precisely control the conditions under which fish is reared. While wild fish takes time to replenish itself, lack of restraint on fishing invariably results in over fishing and extinction of many species. Interestingly a country like India unwittingly put in place a ban of trawling by mechanized boats for two moths during Monsoon to allow adequate time for regeneration. Whatever is done past records show that wild fish harvesting is not growing in tune with the demand for fish and world is increasingly looking at aquaculture to augment availability.
Fish species like Carps, Salmon etc and crustaceans like shrimp are raised by the fish farms and this industry is consistently registering a growth rate of 8-10% annually. Herbivorous fish are much more efficient with the plant material they eat than are herbivorous farm animals. It is estimated that to produce 1kg of fish protein, less than 13.5 kg of grain is used while it takes 61.1kg of grain for beef protein and 38kg for pork protein. There is considerable pressure on land for growing grains to feed cattle while food grains for humans also will have to come from the land. Consider the health benefits of eating more fish and reducing meat consumption that will benefit the mankind immensely. There are serious environmental impacts, such as greenhouse gas emissions, eutrophication of water, and for species such as salmon the need for wild fish to feed the farmed ones. Carp fish that China produces is still considered environmentally disastrous though the impact is confined to local level.Aquaculture fish accounts for more than one third of world fish production with China being the leading producer accounting for about 65% of it while India, distant second could produce only about 5%. World aquaculture is predominated by the Carp fish, about 50% while Shrimps and Salmon trail with 5% and 4% respectively. Environmentalists are up in arms against Aquaculture farming because of the uncontrolled generation of waste which pollutes the water bodies and destroys natural mangroves, adversely affecting the aquatic lives. Also worrisome is the liberal use of antibiotics by the farms to prevent infectious diseases that can wipe out the yield.
With all the problems encountered by the fish farming sector, one naturally wonders whether this mode of food production is sustainable at all. New developments how ever give hope that aquaculture technology can still play a critical role in increasing world fish production without adversely impacting the environment. Filtration of fish waste that is generated in huge quantities and recycling the water can considerably improve the performance of aquaculture farms from the environmental angle. Similarly development of vaccines can preempt the wide scale use of antibiotics. Any comparison of aquaculture with wild fish harvesting may not be relevant because of the severe limitations and constraints in maintaining even the current level of production let alone achieve any positive growth rate. But it is definitely a better alternative to animal meat considering the resources required to raise animals under the input intensive farm conditions.
V.H.POTTY
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