Blue whales are making a comeback in the waters off California, according to a study published in the journal Marine Mammal Science. Apparently their population has rebounded to historic and sustainable levels. An estimated 2,200 California blue whales now swim in the eastern North Pacific, the same number that is believed to have existed before the advent of whaling.
The largest animals in the world, blue whales (Balaenoptera musculus) can grow up to 100 feet in length and weigh up to 200 tons. They were hunted to near extinction in the last century, until hunting was banned in 1966 by the International Whaling Commission. Illegal whaling by the Soviet Union continued for several more years thereafter.
The research study notes that the California blue whale population has plateaued since the 1990s, not because of ship strikes which were previously thought to be hindering their recovery, but because they have reached their carrying capacity, the maximum number that their habitat will support.
These findings have received an overwhelming amount of “good news” coverage in the national and international media. “California blue whale population booms after facing extinction,” reports the UK’s Daily Mail. “California blue whales bounce back to near historic numbers,” states the BBC. “California blue whale population rebounds from whaling,” claims Fox News.
“It’s a conservation success story,” said Cole Monnahan, the study’s lead author and PhD student at the University of Washington. “The recovery of California blue whales from whaling demonstrates the ability of blue whale populations to rebuild under careful management and conservation measures.”
Yet some scientists remain unconvinced.
According to Bruce Mate, the Director of the Marine Mammal Institute at Oregon State University, a major flaw with the study is its assumption that carrying capacity has been unchanged from the early 1900s until now. Given the degree that we have polluted and depleted the oceans, carrying capacity is likely to have significantly decreased over the years, which would mean that blue whales could not have recovered to pre-whaling numbers.
Blue whales feed almost exclusively on krill, tiny shrimp like creatures that live in the world’s oceans. In July 2013, millions of North Pacific krill washed up along 250 miles of shoreline in Northern California and Oregon – the largest die-off ever recorded in the region. No explanation has been found. Marine biologist Dorris Welch, who runs whale watching tours in Monterey, says “Blue whales have been scarce this year . We’ve seen very few this summer, and we believe it’s because we haven’t had enough krill.”
John Calambokidis, a senior research biologist at the Cascadia Research Collective in Washington, states that a big problem with this study is that: “these types of models are based on the assumption that populations aren’t experiencing other threats, like ocean warming.”
Calambokidis points out that the data used in the study for historical catch numbers is an estimate based on Soviet records of whaling fleets in the 1900s, notorious for their inaccuracy. Furthermore, the data used to estimate the current blue whale population, is based on the number of ship strike kills – another unreliable source of information. The actual number of ship strikes is likely underestimated, as blue whales sink when struck, and their deaths often go undetected and unreported.
It is estimated that at least 11 blue whales are struck every year by ships along the California coastline. That is almost 4 times the “potential biological removal” (PBR) level of 3.1 per year, permitted by the U.S. Marine Mammal Protection Act of 1972. The PBR is defined as “the maximum number of animals, excluding natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population.”
Monnahan declares that ship strikes, while undesirable, are not a major threat to California blue whales. In fact, the study states, without clear evidence, that ship traffic could increase 11-fold, without depleting their population.
The title of Monnahan’s thesis is: “Do ship strikes threaten the recovery of endangered eastern North Pacific blue whales?” The answer in the publication is a definite “no” and furthermore, mitigating ship strikes, through changing routes or reducing ship speeds, would have little impact on blue whale numbers. In other words, the report supports carrying on business as usual. Shipping lines can expand, and consumerism can continue unabated with no threat to the California blue whale.
Meanwhile, ship strikes are increasing, ocean pollution is mounting, sea temperatures are rising, and krill populations are declining. The blue whale, like other species on the planet including ourselves, is suffering from a growing threat. Publishing a study purporting that California blue whales have recovered to 97% of their historic levels is misleading and irresponsible.
As with any scientific study, it is important to ask questions: how was this research funded? Whose interests does it serve? The blue whale? The shipping business? Industrial capitalism?
The numbers of California blue whale may have rebounded from the 1960s and stabilized over the last 20 years, but this in no way reflects a global recovery of blue whales. The Antarctic and the north Atlantic blue whale populations are at less than 1% of their historic levels. The blue whale is still endangered worldwide.
“Our findings aren’t meant to deprive California blue whales of protections that they need going forward,” says Monnahan. Yet at the same time, Time.com – which has the largest readership of any weekly magazine – picked up on this study and published: “California’s endangered blue-whale population may not be so endangered after all.” A clear reflection of the laissez-faire attitude our culture has towards the pressing environmental crisis, and a dangerous message for our times.