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  National Geographic 27 Jul 07
California Squid Invasion Threatening "Fish Stick" Species
Richard A. Lovett for National Geographic News

Yahoo News 26 Jul 07
Voracious jumbo squid invade California

Jumbo squid that can grow up to 7 feet long and weigh more than 110 pounds are invading central California waters and preying on local anchovy, hake and other commercial fish populations, according to a study published Tuesday.

An aggressive predator, the Humboldt squid — or Dosidicus gigas — can change its eating habits to consume the food supply favored by tuna and sharks, its closest competitors, according to an article published in the Proceedings of the National Academy of Sciences journal.

"Having a new, voracious predator set up shop here in California may be yet another thing for fishermen to compete with," said the study's co-author, Stanford University researcher Louis Zeidberg.

"That said, if a squid saw a human they would jet the other way."

The jumbo squid used to be found only in the Pacific Ocean's warmest stretches near the equator.

In the last 16 years, it has expanded its territory throughout California waters, and squid have even been found in the icy waters off Alaska, Zeidberg said.

Zeidberg's co-author, Monterey Bay Aquarium Research Institute senior scientist Bruce Robison, first spotted the jumbo squid here in 1997, when one swam past the lens of a camera mounted on a submersible thousands of feet below the ocean's surface. More were observed through 1999, but the squid weren't seen again locally until the fall of 2002.

Since their return, scientists have noted a corresponding drop in the population of Pacific hake, a whitefish the squid feeds on that is often used in fish sticks, Zeidberg said.

"As they've come and gone, the hake have dropped off," Zeidberg said. "We're just beginning to figure out how the pieces fit together, but this is most likely going to shake things up."

Before the 1970s, the giant squid were typically found in the Eastern Pacific, and in coastal waters spanning from Peru to Costa Rica.

But as the populations of its natural predators — like large tuna, sharks and swordfish — declined because of fishing, the squids moved northward and started eating different species that thrive in colder waters.

Local marine mammals needn't worry about the squid's arrival since they're higher up on the food chain, but lanternfish, krill, anchovies and rockfish are all fair game, Zeidberg said.

A fishermen's organization said Tuesday they were monitoring the squid's impact on commercial fisheries.

"In years of high upwellings, when the ocean is just bountiful, it probably wouldn't do anything," Zeke Grader, the executive director of the Pacific Coast Federation of Fishermen's Associations.

"But in bad years it could be a problem to have a new predator competing at the top of the food chain."

National Geographic 27 Jul 07
California Squid Invasion Threatening "Fish Stick" Species
Richard A. Lovett for National Geographic News

A species of 100-pound (45-kilogram) predatory squid previously confined to more tropical climates has taken up residence in coastal California waters, scientists say.

And the invasion of Humboldt squid seems to be making a noticeable dent in the local population of hake, experts note in a new study.

Hake, also known as Pacific whiting, is used to make imitation crab, fish sticks, and other minced-fish products.

Scientists noted a potential threat to hake fisheries when an unusual influx of Humboldt squid along the Pacific coast received widespread media attention in the spring. For the latest study, published this week in the online edition of the Proceedings of the National Academy of Sciences, researchers examined video from submersible dives in Monterey Bay spanning 16 years.

They discovered that the squid have been steadily abundant in the region since 2002. "A top predator has moved in," said study co-author Bruce Robison, a researcher at the Monterey Bay Aquarium Research Institute in Moss Landing.

"This hardly ever happens in terrestrial or marine habitats. Usually, if you get an invading species, it's a snail or crab or something like that." And the squid's sustained presence, the scientists note, coincides with a documented hake decline.

Squid vs. Tuna

Humboldt squid, also called jumbo squid, are voracious hunters with razor-sharp beaks and powerful tentacles. "They are amazing animals," Robison said. "They are big and aggressive and often hunt in packs."

Traditionally the squid have been found mostly in the warm waters of Mexico's Gulf of California. Before 1997, the underwater videos revealed no Humboldt sightings in Monterey Bay, Robison said.

Large numbers of squid appeared in the 1990s when El Niño weather events brought warm water up from the tropics. Then the squid disappeared again, except for occasional stragglers.

In 2002 they reappeared and have been abundant ever since. In addition to moving to California coasts, Robison said, the squid appear to be moving southward into the waters off Chile.

Robison thinks the squid are expanding from their normal range because of declining tuna populations. Historically, he said, the squid and tuna competed for the same prey. In addition, tuna ate baby squid.

But heavy fishing for tuna and other predatory fish is allowing the squid to flourish. When El Niño currents brought the squid north, Robison added, they found an environment where their predators, such as sharks, were also on the decline.

"They're here to stay," Robison said. "We know they're reproducing. We see little ones."

But, except for their ecological impacts, he added, the squid pose no threat to people. "There are a couple of odd stories," he said, "but I don't think they're any threat at all."

Oregon Sardines

William Hanshumaker is a researcher at the Hatfield Marine Science Center in Newport, Oregon. He said that fishers have been finding Humboldt squid at least as far north as the Columbia River, where he believes the squid are hunting sardines. The river forms much of the border between Oregon and Washington State before emptying into the Pacific.

Furthermore, he said, Oregon has seen numerous beachings of dying squid. One possibility is that the squid are being killed by a toxin called domoic acid produced by certain marine plankton.

The toxin works its way up the food chain when sardines eat the plankton and squid eat the sardines.

The entire situation reveals how strongly different parts of the oceans are linked, said study co-author Louis Zeidberg of Stanford University. "[You] could consider the entire Pacific as one ecosystem," he said. "Changes you cause in the tropics can ultimately have an effect all the way to the [temperate] regions."
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