Question

Overfishing of salmon has caused populations of wild salmon to decline. To combat this decline, salmon are raised in hatcheries, and then released to the wild. However, researchers have found that hatchery-raised salmon have reduced reproductive success in the wild, compared to wild salmon. They have also identified many genetic differences between hatchery-raised and wild salmon. Which statement describes the most likely reason for the differences between hatchery-raised and wild salmon? A. The pressures of a hatchery environment and of the wild environment select for different traits. B. Hatchery-raised salmon develop into stronger swimmers than those raised in the wild. C. The pressures of a hatchery environment promote convergent evolution between hatchery-raised and wild salmon. D. Hatchery-raised salmon have evolved to have completely different genomes from those of wild salmon.

Answer 1

Option A, The pressures of a hatchery environment and of the wild environment select for different traits.

The various pressures in wild environment include the competition for food and survival, threat of prey etc. The effect of domestication on salmon can also be a reason for its low productivity in wild environment. Some other factors that might have affected the regular productivity of salmon in wild environment include- captive rearing, inbreeding among close relatives and ability of some fish to adapt to the unique hatchery environment.

Answer 2

the answer option is A