Question

Having some trouble trying to figure this out.

Any help will be appreciated

Concept Questions Size in fish depends on how much food they can find, but is also genetically influenced. A salmon species has large and small individuals. Large fish have a better survival rate because they are too big to be prey for other fish and can swim faster, allowing them to escape dangerous situations. The salmon also prefer larger mates. As a result, most of the fish in an Alaskan bay have been large in the past. The salmon is also an important source of food for humans. Since people have switched from using fish in rods to nets, the average size of fish in the bay has decreased. There are now more small fish in the bay than large fish. Why did the population change? What is the selective pressure on the salmon?

Answer 1

The population change might be a consequence of using nets which selelectively traps the larger salmons with its net size. The procurement of larger salmon has eventually lead to the survival of the smaller salmons, leading to the fall in the number of the larger salmons. Here, the selective pressure on the salmon, lies on the adaptation of the salmon to human fishing. The salmons have to adapt or fit their size to maintain their population, thereby retaining their body size to a much smaller proportion when compared to larger salmons.