Natural La Jolla: They’re here! The gray whale migration is on
By Kelly Stewart
On the Sunday before Thanksgiving, I was sitting having coffee with a friend along the bluffs in town when she said, “I think I saw something out there — a splash.”
Thinking it was probably a diving pelican or a dolphin, I watched the spot for the next minute or so. A blow! It was a gray whale, very close to shore inside the kelp line, and my first sighting of the season. We watched it blow a couple more times before it moved past our vantage point. From now through January, we’ll be seeing more and more of these amazing creatures heading south.
Gray whales (Eschrichtius robustus) undertake one of the most impressive migrations in the world — traveling from northern Alaskan and Russian waters to the warm lagoons of the Baja California peninsula in Mexico, and back again (10,000 to 14,000 miles). During the summer months, they feast on small crustaceans on the seafloor in cold northern waters. As baleen whales, the gray whale filters food through the fringed plates hanging from the roof of their mouth.
In the fall, they begin to head south to warmer waters — the one-way trip can take two to three months. The first ones to arrive to the lagoons of Mexico are the pregnant whales. Here they give birth and nurse their calves. Males and non-pregnant female gray whales join them soon after, mainly for mating. Overall, they stay in the lagoons for two to three months before they make the return trip, arriving back up north for the summer. On the return migration, moms and calves hug the coastline very closely.
Threatening the young whales during this trip are predatory killer whale pods — they will attack both the mother and calf, trying to kill the calf. Gray whales may be seen traveling in groups, but many travel alone or in pairs. They are mottled white over a long dark gray body (about 45 feet long). They have a tapered head and no dorsal fin.
Watch for whales next time you are walking along the shore. Blows are easiest to spot in the late afternoon when the sun has moved down in the sky and the blow is lit from behind (and especially on a windless day, when the misty breath will hang in the air, see photo). Once you see a blow, keep watching because gray whales will usually breathe three to five times about 15 to 30 seconds apart, before you see their tail fluke up and they disappear beneath the surface.
Kelly Stewart, Ph.D. is a postdoc with NOAA’s Southwest Fisheries Science Center. Contact her at NaturalLaJolla@gmail.com.