Question

In cod fishing, older and larger fish are more likely to be retained in nets than younger and smaller fish. Despite the removal of these large breeders, the population is still reproducing. How do you think cod characteristics have changed due to the selection pressure from over-fishing.

a. Selection has led to increased growth rates.
b. Selection has led to decreased growth rates.
c. Selection has led to increases in the age of fish at the age of reproductive maturity.
d. Selection has led to decreases in the size of fish at the age of reproductive maturity.

Answer 1

Answer: Selection has led to increases in the age of fish at the age of reproductive maturity. (Option C)

Explanation:

The population is still reproducing despite the removal of large breeders, because the selection led to the increase in the age of fish at their reproductive stage.

The fish at their reproductive stage have a greater fecundity (i.e eggs laying ability), which in turn brings about influx of numerous fish seeds to the Cod population.