Why do whales eat a huge amount of small fishes instead of a few large ones?

Question

I remember watching a documentary once and learned that whales need to eat tonnes (literally) of krill per day to survive. I don’t understand why this is better than eating small amounts of large fishes instead.

In: 298

Answer 1

Big fish swim faster than smaller fish, so the latter are easier to catch.
There are more small fish and they swim in schools. Distributing themselves across the ocean would make it harder to be eaten, but then each small fish would have to do all the watching out by itself..