For a guess?
How about a capsized squid fishing boat dumped it's haul.
Of course, it seems to me that it's more likely it's a natural phenomenon.
I did some looking about and found that it's been happening for years and scientists don't know for sure what it is.
--- from: National Geographic on 2/23/2005 ( http://tinyurl.com/5mta9 )
Last month thousands of large squid mysteriously beached themselves on California shores.
It was not the first time such a mass "suicide" has occurred. Observers say it seems to happen every few years.
But what causes the Humboldt—or jumbo—squid (Dosidicus gigas) to end up on land?
"We don't know," said William Gilly, a biologist at Stanford University's Hopkins Marine Station in Pacific Grove, California. "It's a mystery of large size what's killing these squid."
Gilly has studied squid for more than two decades and has been tagging the jumbo squid in Mexico's Gulf of California as part of a larger study of their movements in the Pacific Ocean. He speculates that the cause of the recent deaths might be a combination of the squid spending too much time in warm water and the squid eating something toxic.
Sarah Allen, a senior science advisor with the National Park Service at Point Reyes, California, said around 30 squid died on Drakes Beach, north of San Francisco.
The squid did not seem to wash up dead on the shores but instead appeared to swim into shallow water where waves carried them onto the beach. According to Gilly, the Hopkins Marine Station biologist, that suggests there may be something neurologically wrong with the squid.
"They appear to be mentally deranged, not physically ill. It's clearly something abnormal," he said. "They're big-brained, intelligent creatures. It's not like they're attracted to the lights of the city or anything like that."
He speculates that the squid are eating something toxic and that this leads to their aberrant behavior.
The toxin, Gilly said, could be domoic acid, which is produced by several species of microscopic algae known as diatoms.
Studies have shown that domoic acid causes convulsions and even death in marine mammals that feed on the same things that squid do. The acid is found in organisms, including sardines and krill that eat the algae and that are in turn eaten by the squid.
"In addition," Gilly said, "I suspect there is an environmental wild card that augments the effects of the toxin, most likely thermal stress to the squid from spending too much time chasing food and eating in relatively warm surface water." ----