Fish hatchery
A fish hatchery is a place where large numbers of fish eggs are artificially fertilized and fry and are hatched in an enclosed environment. Fish hatcheries can increase a fish population quickly as in the wild only 2% of the eggs survive (versus 80% using a hatchery).[1] Hatcheries may be owned and operated by either governments or private interests. Some hatcheries raise the fry until they reach adulthood and have commercial value; others release the fry into the wild with the intent of building up the wild stock.
Procedures
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Fish hatcheries typically involve a lot of manual labour. A hatchery worker will take a female fish, release her eggs in a bowl (stripping), and then externally add the male fish's sperm (milt), mix them and allow them to fertilize and incubate undisturbed. This, as there is less risk of disease or predation. They can immediately dispose of any unfertilized eggs. What happens next depends on the purpose of the hatchery.
Purposes
Fish farms
Fish farms use hatcheries to cultivate fish to sell for food or ornamental purposes, eliminating the need to find the fish in the wild, and even providing some species outside of their natural season. They raise the fish until they are ready to be eaten or sold to aquarium stores.
Fish stocking
Other hatcheries release the juvenile fish into a river, lake or the ocean to support commercial, tribal, or recreational fishing or to supplement the natural numbers of threatened or endangered species, a practice known as fish stocking. Some fish hatcheries are used to mitigate the effects of development, such as construction of a dam, hydroelectric plant or water diversion. In the United States and Canada, these hatcheries usually raise anadromous fish that are unable to migrate due to the obstruction, particularly salmon and steelhead. In 1889 a cod fish hatchery was erected on an island belonging to Newfoundland and Labrador. It was the largest hatchery in the world at that time and the first in North America.
Ornamental fish
The ornamental fish industry uses fish hatcheries to produce fish for the aquarium fish trade; this has helped to limit the overharvesting of native fish populations both in fresh and salt water ecosystems.
Criticisms
Originally devised to mitigate for fish production lost through development and supply the demand for fishing from an expanding human population, fish hatcheries have been criticized for producing poor quality or genetically inferior fish[citation needed]. Several researchers have raised concerns about hatchery fish potentially breeding with wild fish. Hatchery fish may in some cases compete with wild fish.[2] There is debate among the scientific community regarding the risks and benefits of hatchery programs[citation needed]. Proving negative (or positive) effects of hatchery programs on wild fish is challenging due to numerous other environmental and anthropogenic factors that simultaneously affect fish. In the United States and Canada, there have been several salmon and steelhead hatchery reform projects intended to reduce the possibility of negative impacts from hatchery programs. Most salmon and steelhead hatcheries follow up to date management practices to mitigate potential risks[citation needed].
See also
References
- ^ Edwardian Farm episode 3
- ^ Genetics and the Extinction of Species, Laura F. Landweber and Andrew P. Dobson eds., Princeton University Press (1999)
External links
- Hatcheries and the Protection of Wild Salmon
- University of Washington Libraries Digital Collections -- Digital Collections -- Fish Hatcheries An ongoing digital collection of images related to fish hatcheries.
- [1] - Links to hatchery reform projects
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