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When thinking of endangered species,most people will automatically imagine the large mammals:giant panda bears,rhinos or tigers.However,there are hundreds of smaller species who find themselves on the endangered list.The task of preserving these species and increasing their numbers sufficiently to remove them from the endangered species list falls to citizens;and fish hatcheries(孵化场) would seem to be one such method to achieve this.
The aim of fish hatcheries in aiding endangered species is to breed individuals in a controlled environment for release into the wild in order to increase the number of individuals in the natural population.There are two types of programs with very different focuses.An augmentation(增大) program seeks to increase the natural population for commercial use.The hatchery fish are not intended for integration into the wild population,and generally the fish that are reared in the hatchery become the brood(一窝) stock for the next generation,although straying does occur.Breeding fish in these hatcheries uses a limited genetic pool,which creates a genetic drift from the wild population and limits the genetic variance of the captive bred population in comparison with the wild population.
Programs that are focused specifically on conservation are more beneficial to endangered species.These programs use adults from both the natural population and hatchery origins.The juveniles are kept in a proper facility before they are released into the wild population to continue their life cycle in conjunction(关联) with the wild population.These hatcheries are focused on the long-term increase in the numbers and the fitness of the fish instead of the short-term boost in numbers.There is a constant need for monitoring of the genetic and ecological impact(影响) of the program to ensure that the hatchery-bred fish do not replace the natural fish.
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