Question

For evolution, each answer should not exceed a typed page—they can be shorter. Concise, to-the-point answers will be looked upon favorably.

A study of a sea bass population finds that fish often lived for a hundred years in nature before the advent of fishing by humans. Since the 1950s, however, this population has been heavily fished, limiting lifespans to around five years. If fishing of this population were stopped entirely,  what evolutionary changes would you expect to see in life-history traits compared to the pre-1950s fish population? What effects might these changes have on the ecology of the fish population?

Answer 1

According to the information, no fishing by humans allowed the fishes to have long lives, upto 100 years. But fishing by humans reduced the life span to 5 years. In this regard, if the fishing is again prevented, it is highly expected that the fishes would tend to live a longer life duration.

Although fishes would live longer life-spans, this practice would tend to eliminate the chances of evolution in the fish population. When humans were hunting for fishes, the fishes experienced a shorter life-span and tended to develop genetic strategies to live more, hence underwent variation and evolution. If this hunting is stopped altogether, the fishes will not any more need to evolve for enhancing their life span and hence would not evolve.

Thus, no-hunting will prevent evolution of these fish populations and hence ecological remodelling will not take place.