Answer:
Beat more baleen whales
Explanation:
Smaller toothed whales are secondary consumers of fish. If the fish population declined, the populations of leopard seals, elephant seals, and penguins; animals which make up a large portion of the whales' diet; would likely also decline.
To survive, the smaller toothed whales would have to eat more animals that feed primarily on krill instead of fish, such as seals (not leopard or elephant seals) and baleen whales.