D
When thinking of endangered species, most people will automatically imagine the large mammals: giant pandas, 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 longterm increase in the numbers and the fitness of the fish instead of the shortterm boost in numbers. There is a constant need for monitoring of the genetic and ecological impact of the program to ensure that the hatcherybred fish do not replace the natural fish.
The research is still ongoing, and more is being learned about the impact of fish hatcheries on the natural population and what can be done to minimize the negative effects. With an increase in the awareness of the effects of hatcheries on the natural population, more steps can be taken to reduce this impact and the conservation efforts will improve.
语篇解读：本文是科普阅读文，介绍了濒临灭绝鱼类的人工孵化，通过孵化可以增加它们的数量，避免灭绝。
32．What is the main purpose of fish hatcheries?
A．To increase fish numbers for commercial use.
B．To raise people's awareness of endangered fish.
C．To increase the number of endangered fish species.
D．To help endangered fish survive in the wild.
解析：选C 细节理解题。从文章第一段最后一句“The task of preserving these species and increasing their numbers sufficiently to remove them from the endangered species list falls to citizens ...”可知，人工孵化是通过增加濒临灭绝鱼类的数量，避免它们灭绝。
33．What do we know about fish produced from augmentation program?
A．They are usually released into the wild.
B．They become the brood stock for the next generation.
C．They are mixed with the wild population.
D．They are used to improve genetic pool.
解析：选B 细节理解题。从文章第二段“... generally the fish that are reared in the hatchery become the brood stock for the next generation ...”可知，增量项目孵化的鱼是作为下一代种鱼来储存的。
34．What is the disadvantage of augmentation program?
A．Straying often occurs during the process.
B．It increases fish numbers too quickly.
C．It has a limit genetic pool of the fish.
D．It can harm the natural fish.
解析：选C 细节理解题。从文章第二段“Breeding fish in these hatcheries uses a limited genetic pool ...”可知，增量孵化时，所使用的基因库有限。
35．Which of the following is TRUE about programs focused specifically on conservation?
A．They use a more variant genetic pool.
B．They are carried out in a natural environment.
C．They use only adults from natural population.
D．They produce perfect natural fish.
解析：选A 推理判断题。从文章第三段可知，第二种人工孵化使用人工培育的鱼和野外的鱼杂交，因此这种孵化方式所使用的基因库更多样。
