LAGUNA SAN IGNACIO, Mexico — Monday, March 31, 2008 | In the darkness of night, he could hear the whales calling. From out there, out across the lagoon’s barren expanse, came the sound of gray whales surfacing, spouting a misty breath of air, then gasping for more before diving.
Four decades have passed since Pachico Mayoral first encountered the eastern Pacific gray whales that come each winter to this isolated lagoon 475 miles south of San Diego. In the years since he traded an itinerant existence on a merchant freighter for life as a fisherman, he has seen changes in the whales that pass by San Diego’s shores annually to nurse their young in the predator-free waters here for four months.
What scientists have concluded from research spanning decades, the 67-year-old has observed anecdotally from his home on the lagoon’s sandy shores. Since 1985, Mayoral says fewer whales have used the lagoon. And while the whales once returned from their Alaskan feeding grounds at the start of December, they’ve gradually begun showing up in late December, he says, spending less time before returning north to the Arctic.
Scientists studying the whales in the lagoon confirm Mayoral’s observations. The whales’ fall migration south past San Diego is peaking five days later than it once did. Once they get to Baja, they’re staying two weeks less than they did in the late 1970s. Back then, scientists conducting occasional population censuses here counted as many as 400 adult whales in a day. Last year, censuses found half that. And 12 percent of the whales that did stay in the lagoon in 2007 showed signs of malnutrition, a phenomenon dubbed “skinny whale syndrome.”
Gray whales, massive barnacle-encrusted mammals about the same weight and length as a large school bus, swim nearly 12,000 miles each year, spending summers feeding in the rich waters near Alaska and winters raising calves in four lagoons on Baja California’s Pacific coast. The whale known as Eschrichtius robustus lures curious tourists to San Diego, inspires crowds at Cabrillo National Monument and fuels both the local whale-watching industry as well as small ecotourism camps in coastal Baja.
But the gray whales are changing, and scientists studying them in Laguna San Ignacio say they believe climate change is responsible for causing a subtle shift at the base of the Arctic food chain that has magnified as it has rippled upward, forcing the whales to switch their feeding and migration patterns.