The official numbers are in for the counters of the gray whales that migrated past Coal Oil Point earlier this year. The good news? Volunteer counter population went up. The bad news? The population of gray whales migrating northbound near the shore this year went down from last year’s count.
So far down, in fact, that counters this year picked up less than half of the northbound calves they did last year. Similar studies up and down the coast have come out with the same results
“There are theories, some of them quite complicated,” said Michael Smith, project coodinator of Gray Whales Count, a joint project of the American Cetacean Society, UCSB’s Coal Oil Point Reserve, UCSD’s Scripps Institute and the Cascadia Research Collective in Washington.
From January to May, he and several volunteers head out to Coal Oil Point every day and scan the waters for evidence of the mothers, calves and juveniles that tend to travel north near the shore to avoid the rougher waters and predators. Males and mature whales tend to travel farther away from the coast, where the water is colder and the currents are stronger.
One of the possible reasons for the steep decline in whales, said Smith, is that pregnant mothers got iced out of their food sources and miscarried. Or, due to global warming, pregnant whales traveled farther up north to feed, and gave birth to their young before they could reach the warm waters of Mexico, and the infants, with no blubber, died from the cold. Another theory is that while the mature population thrived, they just didn’t produce many young. Many other factors could have affected the count, said Smith, pointing out that he and the volunteers were only out there eight hours a day.
A decline like this has happened before, said Smith.
“Almost ten years ago the population crashed after being stable for quite a period of time,” he said.
The belief at the time was that the population had reached carrying capacity, and the ocean was no longer able to sustain a continuously growing population of whales. The population has since rebounded, but while the ocean has been able to sustain greater numbers of whales in the past, it’s possible, said Smith, that the ocean itself has changed and is less able to support the numbers of whales it has previously.
It will be quite a while before Smith and company will be able to determine the cause of this decline, and if indeed it is a normal behavior of gray whale populations over time. There were no human-caused detrimental effects other than the broad global climate problem, he said, and from his observation post at Coal Oil Point, no new manmade environmental problems seem to have occurred.
“There was nothing disturbing the whales abnormally,” he said. “There was the usual noise and boat traffic, but the whales seemed to tolerate that to some degree.”
The whales travel fairly close to Coal Oil Point, and swim within fishing, boating, sightseeing and oil and gas operations in the area.
Next whale-counting season, Scripps Oceanographic Institute will be participating in the project by putting passive acoustic equipment in the water, and will try to correlate sounds in the migration path with behaviors the volunteers observe. Other plans, said Smith, include potentially observing from Platform Holly to add to their sampling area.
For more information about Gray Whales Count and to become a volunteer, visit www.acschannelislands.org.