Blue whales return to Californian waters

Once again, several blue whales are living off the coast around Palos Verdes Peninsula - the Los Angeles/South Bay area of California. It’s the third consecutive summer this species have returned to the region.

It is the abundance of krill (a shrimp-like creature about the size of a thumbnail), that brings them into the area, and the whales have to eat a lot — up to 7,000 pounds, or 40 million krill, a day!

Blue whales feed almost exclusively on krill, though they also take small numbers of copepods. Spotting blue whales can be a challenge, harder than spotting the gray whales that migrate up and down the California coast each year. That is because the blue whales spend most of their time well below the surface, coming up every eight to 12 minutes to breathe before diving back down.

Blue whales were seen regularly in the area in the first half of the century but in the early 1920s, whaling changed and became more industrialised. Whaling ships killed blue whales worldwide and the number of whales dropped to less than 20,000 by the time their hunting was banned in 1967.

Since the introduction of the whaling ban, studies have failed to ascertain whether the global blue whale population is increasing or remaining stable and the species remains listed as "endangered" on the IUCN Red List of threatened species.

They are the largest creatures that exist on the planet, sometimes reaching more than 100 feet long. Due to their enormous size, power and speed, adult blue whales nowadays have virtually no natural predators.