The whale season to end all whale seasons has scientists searching for explanations
The last year has been bliss for whale fanatics like myself.
I have pictures of whales pinned up in my bedroom, look for them almost every day on West Cliff, and read any article about them that I come across. I am even considering getting a whale tattoo. So the fall of 2013 was the beginning of a special time.
That’s when the Monterey Bay began to see an unprecedented amount of whale activity, particularly from humpbacks—so much so that the past year has been called “The Year of Abundance” by media like Monterey County Weekly and researchers like Jodi Frediani, who gave a talk on the subject last month. The trend hasn’t shown signs of slowing.
It’s not just the humpbacks that have been active. There have been reports about flocks of pelicans in the tens of thousands. And many may remember the feeding frenzy last Thanksgiving, when hundreds of sea lions, birds and whales were chowing down right off shore; the event was so remarkable it made The New York Times. Then there’s the unforgettably pungent fish die-off last month in the Santa Cruz Harbor, where schools of anchovies were trapped in the harbor, and died in droves due to lack of oxygen. All of this activity has led locals to wonder: what the heck is going on? Is this normal? And is it going to continue? Unfortunately, as is often the case with science, there are no easy answers, but scientists do have some intriguing leads.
One of the reasons we are seeing more whales is simply that there are more whales in general. “When I started doing this, in the late ’80s, there were only 400 humpbacks,” says Nancy Black, a marine biologist and owner of the whale-watching company Monterey Bay Whale Watch. “But since they’ve been protected, their numbers have increased over the years by six percent a year. There are about 2,500 [now].”
So, more whales mean more whales to see. (Humpbacks were placed on the endangered species list in 1970.) The same is true for other animals that have been protected, like sea otters, which were once almost hunted to extinction.
But what has been remarkable about this year is that the humpbacks have been sticking around for so long. Typically they come into the bay, eat up what is here, then move on to other feeding spots. These past 12 months, the whales have been more concentrated and slower to move on.
That leads us to the next reason we have seen so many humpbacks: anchovies.
The last year has seen huge numbers of anchovies. The spawn of anchovies is likely related to a 25-year oscillation between anchovies and sardines, a phenomenon that has been catalogued by Francisco Chavez of the Monterey Bay Aquarium Research Institute.
Every 25 years, the California coast fluxes between a “sardine regime” and an “anchovy regime.” During a “sardine regime,” there are historically tons of sardines, warmer ocean temperatures off the coast of California, and fewer nutrients in the water. An anchovy regime, which we entered at the beginning of the new millennium, is typified by the opposite: cooler water, more nutrients and tons of anchovies.
But in fact, the ocean hasn’t been cold. It’s actually been warmer than average. On July 28, the Pacific reached the highest recorded temperature of 67.5 F, 10 degrees higher than past July averages.
The warmer waters may be related to a strange wind pattern. Starting in the spring, the winds usually blow from the northwest, causing an upwelling of deeper, colder waters. We had a windy spring, like normal, which likely began the upwelling of these colder waters. These northwest winds usually continue, but not this summer. Instead, we saw lots of south winds, which bring warmer water.
It’s hard to get a clear answer on why the southern winds blew during the summer, because no one really seems to know. “It’s incredibly complex,” said Frediani, a researcher and wild-life photographer. “What I do know is the scientists don’t fully understand it.”
In consulting with a handful of experts and reading reports about this strange year, that was a constant refrain. The theory about wind patterns is speculation, and we are likely years away from really understanding what has been going on in the atmosphere. Some scientists are even critical of Chavez’s theory about sardines and anchovies. His data goes back only 100 years, and older records of marine sediments tracing back thousands of years suggest that there were times when both groups were in high populations.
It’s hard to say if any of this can really be considered “normal,” especially because populations of many marine animals are still recovering from being heavily hunted and fished.
“What we are seeing is not unlike some pre-colonial accounts,” said Frediani, pointing to books such as “The Ohlone Way,” which describes life in the Monterey Bay before Spanish settlers.
So, I ask Black while on a whale-watching trip, is this all going to continue?
“I would love that,” she says. Her whale-watching business has been booming since word of the amazing phenomenon circulated around the U.S. and the globe. “But really, there is no telling.”