How big of a fish can a baleen whale eat?

The baleen plates are worn down by the whale's tongue, but they also grow back like fingernails. Whales have hundreds of baleen plates. For example, the humpback whale has 400 baleen plates, each of which is 25 inches to 30 inches long (64 cm to 76 cm), 13 inches (33 cm) wide and less than 0.2 inches (0.5 cm) thick [source: MacMillan]. read more

The primary reason why baleen whales are able to get so large is that instead of feeding on larger organisms, where there's ultimately less available energy, they focus on trophic layer 2 of this monumentally productive system, and eat the zooplankton directly. read more