Overfishing of stocks of fish species, like salmon and cod, in an effort to meet a growing global demand has become an international concern. A recent estimate indicates that the average annual consumption of fish globally in 2014 was about twice the consumption in 1960. Because of increased concerns about the impact of overfishing, fishery managers are looking for ways to protect wild populations while still satisfying global demand for food for human consumption. Which of the following techniques could best reduce the harmful effects of overfishing if it were to be widely adopted by the fishing industry?
A. Increased use of large-mesh gill nets for harvesting salmon and trout.
B. Greater reliance on bottom trawling in coastal waters for harvesting shrimp and sole.
C. Increased use of long-line fishing techniques in the open ocean for harvesting swordfish and halibut.
D. Widespread application of cyanide in tropical waters for harvesting tuna and cod.

Overfishing usually lead to catching of young and fertile salmon and trout. These young fishes are responsible for producing more young salmon and trout. Since they get entrapped easily in small sized mesh wire net, they could not reproduce due to which the number of salmon and trout killed becomes higher than the number of salmon and trout reproduced.

Using large mesh sized net will only capture bigger fish which do not contribute much to the future generation, thereby catering present demand along with making way for meeting out future demands as well.

Hence, option A is correct