Answer:
There will be no impact on the whale’s population.
Step-by-step explanation:
Barnacles and whales have a commensalistic relationship which is a kind of symbiotic relationship. In this kind of symbiotic relationship, two species live in association with each other where one species gets the benefit of this relationship while the other is neither harmed nor benefited.
In the case of barnacles and whales, barnacles are the species which gets benefited from this relationship as they attach to the belly or back of a whale’s body and then feed on the microorganisms while whales are neither befitted nor harmed by this association. Thus, if barnacles population decreases there would be no impact on the whale’s population.