Killer Consequences: Has whaling driven orcas to a diet of sea lions?

From the 1970s to the 1990s, populations of sea otters and some pinnipeds, including Steller sea lions and fur seals, took a mysterious nosedive in the northern Pacific. A new study floats a surprising explanation: These creatures became choice entrées for killer whales after industrial whaling wiped out the great whales that killer whales had been eating.