What is the niche of the shark whales?

The whale sharks niche in the environment is essentially population control. The whale shark spends all day eating and without it the populations of krill and plankton would increase by a large amount.

Explanation:

Whale sharks have a broad distribution in tropical and warm temperate seas, usually between latitudes 30°N and 35°S. They are known to inhabit both deep and shallow coastal waters and the lagoons of coral atolls and reefs. Australia is one of the most reliable locations to find whale sharks. It is very difficult to conduct research on the shark's role in the ecosystem so scientists aren't sure what would happen if sharks became extinct. ... If the whale shark becomes extinct, there might be an increase in plankton. However, plankton are also eaten by several species of whale. Whale sharks are one of the most amazing animals in the world — and while they may be sharks, they're also one of the most gentle fish in the sea. In fact, whale sharks are so gentle, they're completely safe to swim around. Our Whale Shark Encounter tour gives you the opportunity to do just that.

That's one scary shoork-

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.