"Squid and other soft-bodied invertebrates have almost open circulatory systems, so they're closely linked to their physical environment," Aran Mooney, a biologist at WHOI, said in a statement. "As the ocean environment changes, they probably change a lot in response." To test this point, the researchers developed the ITAG, a device that not only measures the surrounding oceanic conditions but also how the animal reacts and adapts to them.
At just 4.25- x 2.5-inches, the ITAG is far smaller than the conventional acoustic tags used to monitor marine vertebrates like dolphins and is more accurate than earlier small-scale trackers fitted to large squid. It's also shaped to minimize the amount of drag it generates, so as not to put undue burden or strain on the animal the device is attached to. "We wanted a tag that would be able to tell us what the animal is doing at that depth—is it hovering or swimming faster or slower? When squid go down to a couple hundred meters, are they foraging at night at that depth, or are they resting and getting away from top predators? What are their respiration rates? These are the types of behavior questions we wanted to answer," Mooney said.
[Image Credit: Barcroft Media via Getty Images, WHOI]