Humboldt squid live at depths of 660 to 2,300 feet in the eastern Pacific, ranging from Tierra del Fuego, an archipelago off the southernmost tip of the South American mainland, north to California. Recently, the squid have been appearing further north, as far as Sitka, Alaska, raising alarm about ecological problems possibly underlying the northward migration.
“You typically don’t expect to see them in U.S. waters,’’ Benoit-Bird said. “Usually they are in areas south. For the last decade or so, however, you can see them in the summer along the entire west coast of the United States, all the way up to the Gulf of Alaska.”
Jumbo squid can grow to human size, about six feet, and weigh as much as 100 pounds. They grow quickly, with a typical lifespan no longer than two years.
“One of the reasons these squid are ecologically interesting is that they attain their size in a year or two. They are an incredibly fast-growing species, which means they eat a lot,’’ Benoit-Bird said. “We are learning that they are very flexible predators; they can eat anything from tiny krill to things as big as they are.’’
Mexican fishermen call them diablos rojos, or “red devils,’’ because they are extremely aggressive. “I don’t think I would choose to get in the water with them when they are actively feeding,’’ Benoit-Bird said, noting, however, that they lose their propulsion when captured. Even so, “you don’t want to stick your fingers in their mouths,’’ she added.
The researchers located the squid with sophisticated sonar technology, Benoit-Bird’s field of expertise. “We emit a short pulse of sound and wait for it to travel,’’ she explained. “It hits the school and bounces back, and that’s how we can determine where they are. We use multiple frequencies at the same time, different pitches of sound, all above our hearing range. The squid have a unique frequency signature, so we can distinguish them from other fish.’’
Many scientists previously believed that sonar signals would not reflect off of squid. Apparently, they were wrong. “We’re not exactly sure why they reflect sound so well, but they do,’’ Benoit-Bird said. “We can distinguish individual squid, not just schools. It really gives us the possibilities of studying squid in ways we’ve never done before.’’