Where are whales in the food chain?
It largely depends on the whale.
Toothed whales (such as the Sperm and Killer whales) are usually
considered to be apex predators. Due to their size and hunting
strategies their only main predator is humans (who are usually
disregarded from such systems).
Baleen whales (such as the Humpback and Blue whales) cannot be
considered such as, though they are often protected by their
immense size, their young are regularly hunted by other large
predators, especially the toothed whales.