Can squid warn us of major quakes?

The Yomiuri Shimbun

Squid fishermen in Tokushima Prefecture hauled in a bumper catch just before the massive March 11 earthquake, just as they did right before the 1995 Great Hanshin Earthquake, leading to suggestions the phenomenons could be connected.

Some fishermen believe a large haul of squid might be a sign that a major earthquake is about to strike, a theory one expert called "intriguing."

A fishery cooperative in Komatsushima in the prefecture said about 200 tons of squid were landed during the peak months of January and February--between two and four times more than in a regular year. A fishery co-op in northern Tokushima reported this winter's squid catch of 70 tons was triple that of a standard year.

Most of the prefecture's squid haul is netted between northeastern Shikoku and Wakayama Prefecture.

A fishery cooperative in Arida, Wakayama Prefecture, which is across the water from Tokushima, also hauled in 700 kilograms, triple a normal season's catch.

According to Agriculture, Forestry and Fisheries Ministry statistics, squid fishermen in Tokushima brought in 491 tons of the cephalopods in 1994--just before the Hanshin quake--which was 1.4 times the 1993 catch and 1.9 times the 1992 catch.

The "fisherman's tale" that the size of a squid catch can foretell earthquakes gained traction, and reports of the phenomenon continue to be made at briefings on possible precursors to earthquakes.

"There were amazing hauls of squid just before the Hanshin quake, and also just before the 1946 Nankai Earthquake," one veteran fisherman from southern Tokushima said.

Another was unable to hide his amazement at the possible connection.

"I thought it was odd that we got such a huge haul," he said. "I'd heard that squid catches increase before a major earthquake, but...."

A fisheries research institute in the prefecture believes last year's summer heat wave might be a more likely explanation for the abundance of squid.

"The sea temperature was warmer than usual last year, which helped the hatching rate of squid eggs," an official of the institute said. The institute believes squid in Osaka Bay and the eastern part of the Seto Inland Sea headed south in search of warmer water in the Kuroshio current when winter arrived, and massed in waters between the Kii Peninsula, northeastern Shikoku and Hyogo Prefecture's Awajishima island--making for a bumper catch in that area.

When asked if there was a connection between squid catches and earthquakes, the official said, "I honestly don't know."

However, Toshiyasu Nagao, a professor at Tokai University's Graduate School of Marine Science and Technology in Shizuoka, said there have been suggestions that catches of deep-sea fish and horse mackerel increase just before a big earthquake, and there have long been reports of possible links between animal behavior and earthquakes.

"It's intriguing," said Nagao, an expert on geophysics. "These fishermen are out at sea every day, so if they say it's happening, then the theory could be quite plausible."