Hundreds of millions of eggplant-colored sea urchins are devouring our state’s pristine, undulating kelp forests by the literal mile. Now, their insatiable stampede seems to be ascending northern California's coastline, reaching as far as Oregon.
According to the Associated Press (AP) via the Scientific Reports, these voracious urchins – which commonly get as large as a human palm – are slowly marching north toward Oregon’s coastal reefs, now having already decimated 90 percent of the kelp forests along the Golden State’s coastline. Adding insult to injury, the AP reported that 350 million purple urchins were estimated to be in a single Oregon reef, alone.
That population count, too, is a 10,000 percent increase from a prior like-area survey conducted in 2014. But, even before then, the faunal red flags were waving in the wind.
“The first sign of trouble arose in 2013 when sea stars in the area were hit with a mysterious disease and began “wast[ing] to nothing,” said the University of California, Davis (UC Davis) in a statement, per ScienceDaily. “Sea stars play an important role in their ecosystem, preying on native purple urchins and keeping their numbers in check. With mass numbers of sea stars dead, the urchins proliferated, chomping their way through the kelp forests.”
As SFist reported on back in 2016, on the tail-end of the mass starfish die-off that began in 2013 (see the correlation?), these celestial cnidarians suffered a catastrophic blow to their population, leaving said episcopal-colored critters to run amok.
Expansive "urchin barrens" — swaths of stripped, naked seafloor that are carpeted only by these sea porcupines — have become common along the NorCal coastline, but they’re now showing up in Oregon's once luscious kelp forests.
And, in doing so, these overpopulated urchins are responsible for killing-off marine biodiversity and crippling fisheries. For example, species like California’s beloved red abalone currently number 96 percent less than they did a few years ago; conversely, the state's purple sea urchin population multiplied by six during that time. Each of these stats was released earlier this week by UC Davis.
In 2018, California had to close down its red abalone fisheries, responsible for an estimated $44 million in “coastal economy” per year, due to the population decline. Oregon followed suit in a similar fashion, suspending permits to some 300 abalone drivers for the next three years, in order to give the remaining red abalone a chance to breed and repopulate, sans commercial harvesting.
“That’s a huge economic loss for our small coastal communities,” said Cynthia Catton, a research associate with the UC Davis Bodega Marine Lab, told the AP. “In California, there were 30,000 to 40,000 participants in [the abalone] fishery every year for decades, and for the first time ever that fishery had to close.”
The solution to this oceanic catastrophe? Well, it’s by no means a one-size-fits-all approach. Researchers believe that, even under the most ideal culling scenarios, it could take upwards of 20 years to clear 100 million pounds of overpopulated purple sea urchins – from just a single reef, no less. Extrapolate that figure out further, and it’s a hellish scenario that offers little in the way of hope.
However, “urchin farming” – physically removing large numbers of purple sea urchins from these kelp forest to be “fattened up” in controlled environments for human consumption (uni), in lieu of traditional red sea urchin row – in tandem with legal urchin hunting and bolstering populations of natural predators (starfish, stingray, sea otters, horn and leopard sharks) offers some semblance of ecological success.
For more information on how you can help support ocean conservation, visit montereybayaquarium.org/conservation-and-science to learn how even the smallest positive impact can ripple out for generations to come.
Image: Flickr via brewbooks