Question

small - scale fishing performed with nets is one of the most common fishing methods used around the world. one of the unfortunate side effects of this method is that sea turtles, which are considered threatened, get caught in the nets along with the fish. conservation biologists at the university of exeter in england recently devised a way to prevent these sea turtle deaths, which they tested at a fishery in northern peru. they found that attaching green led lights to the nets warned the turtles away, possibly because the lights made the nets more visible. the number of sea turtle deaths was reduced, but the number of fish caught seemed to remain the same. what is the main, or central, idea of the passage? to prevent turtles from becoming caught in fishing nets, conservation biologists attached led lights to the nets. one problem with small - catch fishing is that sea turtles get caught along with fish. conservation biologists are researching ways to save the threatened sea turtle population.

Explanation:

The passage focuses on the issue of sea turtles being caught in fishing nets during small - scale fishing and the efforts of conservation biologists (by attaching LED lights to nets) to reduce turtle deaths. The main idea should encapsulate this core topic. The first option "Conservation biologists are researching ways to save the threatened sea turtle population" is too broad as the passage specifically focuses on the method of using LED lights to prevent turtle deaths in fishing nets. The second option "One problem with small - catch fishing is that sea turtles get caught along with fish" only states the problem, while the third option "To prevent turtles from becoming caught in fishing nets, conservation biologists attached LED lights to the nets" accurately summarizes the main action (conservation biologists' method) and the purpose (preventing turtle deaths in nets) which is the central idea of the passage.

Answer:

To prevent turtles from becoming caught in fishing nets, conservation biologists attached LED lights to the nets.