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 have evolved to have completely different genomes from those of wild salmon.
C.
Hatchery-raised salmon develop into stronger swimmers than those raised in the wild.
D.
The pressures of a hatchery environment promote convergent evolution between hatchery-raised and wild salmon.

Answer 1

The correct answer is A. The pressures of a hatchery environment and of the wild environment select for different traits

The reason for the different trait of salmon that lived in hatchery to that of wild salmon is that, they were kept in different environmental conditions. The salmon that lived in hatcheries had no pressure and competition there but once they were placed with wild, the competition for survival raised and led to the reduced reproductive success.