APTOS -- Hundreds of Humboldt squid washed up on Santa Cruz County beaches Sunday in a mass stranding that is not uncommon but remains somewhat of a mystery to marine scientists.
The even more intriguing question, they say, is why the voracious feeders, also called jumbo flying squid, began venturing up to the Central Coast in 2000 from the Sea of Cortez and other warmer spots -- and what their effect is on the ocean environment.
As for the stranding, Hopkins University researcher William Gilly said mass strandings are common when squid invade a new area. In late October, about 100 washed up in Pacific Grove.
They stop if squid colonize successfully or leave the area, Gilly said, a pattern common on the West Coast between 2002-2009.
"My theory is that when the squid invade a new area -- they are returning to Monterey Bay for the first time in nearly three years, and the squid are only 8 or 9 months old -- they follow an algorithm (which is to) swim and find productive areas, especially by investigating anomalies, until you run into trouble," he said. "That mission takes some of them onto the beach. The question I can't answer is why they stop doing this after they successfully colonize an area. Perhaps the real pioneers are selected out, or maybe the survivors of a stranding go back to sea and warn the others."
Gilly, who has studied squid for years, said the stranded squid collected have been normal, well-fed, immature squid. Scientists say not to touch or eat them, as they might contain toxins.
John Field, a Santa Cruz research biologist with the National Marine Fisheries Service, said he picked up some squid off West Cliff Drive on Monday, while several Sentinel readers reported hundreds of squid had washed up at Rio del Mar, Seascape and Pleasure Point beaches.
"I think a lot of stranding is just losing track where they are in surface waters," Field said. "They are in deep water, 200 to 400 meters, during the day and come up to feed at night. And there is a strong onshore transport of oceanic water this type of year and they might get trapped over the shelf and not know where to go, so they just keep feeding and foraging and wash up."
Humboldt squid have been seen in Monterey Bay in significant numbers since 2000, usually around this time of year, and even without warming El Niño influences, he said. Scientists have found some domoic acid, a toxin produced by algae, in beached squid, but the findings were inconclusive, he said.
On the Sand
Many of the squid remained on the sand at Rio del Mar State Beach on Monday, where a sea of crying seagulls gorged themselves.
Colette Crawford of Corralitos said her husband saw a lot of squid while fishing during the weekend and caught a few. Most calamari in local restaurants is from the smaller market squid, marine scientists said.
"He couldn't get past the squid to get to the rockfish," she said.
John Stonich of Aptos said he always worries pollution is to blame when he sees such a die-off.
"I remember when there was a huge anchovy die-off in the harbor and no one knew why," he said. "But I always wonder what happened in the environment that causes it."
Baldo Marinovic, a research biologist with the Institute of Marine Science at UC Santa Cruz, wonders how many squid are in local waters, what is driving them here and how they will affect the ecosystem.
"The biggest story is the fact that they are here," Marinovic said. "They have typically had a more warm water distribution and seem to come up during warm water incursions like El Niño, but have been found here even during cold water conditions. They hang out near what we call the oxygen minimum level, where they hunt sluggish prey, and that level has shoaled and expanded."
Fun squid facts
Humboldt squid are an opportunistic top predator with a voracious appetite, he said.
"It's all very interesting stuff, and there are a lot of theories, but the bottom line is no one knows," Marinovic said.
The dark red squid beached this weekend are 2 to 3 feet long with enormous eyes and long tentacles extending from their mouth. Their predators include blue sharks, sperm whales and Risso's dolphins. They eat 50 to 60 different species of fish, can change their size from generation to generation to cope with varying food supplies, and can reproduce in huge numbers. The larger females produce translucent egg sacks the size of a small car containing 20 million to 30 million eggs.
"If you designed an animal to do well during climate change, it would be this squid," Gilly said.
The Monterey County Herald contributed to this story.
Follow Sentinel reporter Cathy Kelly on Twitter at Twitter.com/cathykelly9