There’s an Explanation for What’s Killing Thousands of Squid in California

For residents of the central California coast, there might finally be an explanation for the thousands of dead squid that have littered their beaches this week. The dead cephalopods have been a big mystery in the past, but marine biologists now think it has something to do with the algae that causes red tides. Live Science writes:

But a few intriguing clues suggest poisonous algae that form so-called red tides may be intoxicating the Humboldt squid and causing the disoriented animals to swim ashore in Monterey Bay, said William Gilly, a marine biologist at Stanford University’s Hopkins Marine Station in Pacific Grove, Calif.

Each of the strandings has corresponded to a red tide, in which algae bloom and release an extremely potent brain toxin, Gilly said. This fall, the red tides have occurred every three weeks, around the same time as the squid beachings, he said. (The squid have been stranding in large numbers for years, with no known cause.)

Of course, this is a correlation, and the exact mechanism that’s killing the squids still isn’t known. This also isn’t the first time that squid have thrown themselves ashore. Humbolt squid, an aggressive predatory species, have been reported on beaches for years. They’ve slowly made their way north, all the way to Santa Cruz. SFGate spoke with Hannah Rosen, a graduate student at the Hopkins Marine Station:

Rosen said the voracious squid, known scientifically as Dosidicus gigas, were last seen in Monterey Bay in 2010. The squid in the bay have primarily been juvenile squid, she said, probably because the young need to feed in a bay until they are big enough to head south. The animals can live up to 2 years.

Humbolt squid look like this in the water:

And this when they wash up dead, on land:

 

More from Smithsonian.com:

VIDEO: This Deep-Sea Squid Breaks Off Its Own Arms to Confuse Predators
Fourteen Fun Facts About Squid, Octopuses and Other Cephalopods

Rose Eveleth | | READ MORE

Rose Eveleth was a writer for Smart News and a producer/designer/ science writer/ animator based in Brooklyn. Her work has appeared in the New York Times, Scientific American, Story Collider, TED-Ed and OnEarth.