On the hunt for deep-living animals

November 10, 2013

Left, Ben Burford, former summer intern, helps Kris Walz, Stephanie Bush, and Freya Goetz sort through the trawl collection. Right, Ben jigging for Humboldt squid.

Left, Ben Burford, former summer intern, helps Kris Walz, Stephanie Bush, and Freya Goetz sort through the trawl collection. Right, Ben jigging for Humboldt squid.

I am very excited to be out to sea on the Western Flyer for the second time in only five months. What a blast! Mostly I have been working, with help from members of the Midwater Ecology Lab, to prepare my intern project on the behavior of the mesopelagic squid, Chiroteuthis calyx, for publication. This mostly involves writing and other computer-based activities, but I am also taking additional observational data when we come across C. calyx with the ROV. When I take breaks from the editing process, I can usually be found in the control room watching the live ROV footage, operating the annotation station, or at the controls of the ROV camera. We have seen some spectacular animals thus far, including the enormous medusa, Stygiomedusa gigantea (see yesterday’s post for a photo). At night, we usually trawl for midwater organisms. I try my best to help sort through all of the animals we end up collecting and everyone does a great job of helping me learn the names of the organisms we catch.

Left, a juvenile Chiroteuthis calyx. Right, Dosidicus gigas.

Left, a juvenile Chiroteuthis calyx. Right, Dosidicus gigas.

While onboard I, along with members of the science party and crew, have been jigging for Humboldt squid, Doscidicus gigas, at night. Jigging is a fishing practice where we jiggle the lure up and down to attract the squid instead of casting the line far out and reeling in. Populations of this large and aggressive squid have been making unpredictable appearances in the waters off Monterey Bay for some time now. I am collecting these squid for William Gilly of Hopkins Marine Station of Stanford University. His team will be using them as part of their studies documenting the physiology, biology, and ecology of D. gigas. They are particularly concerned with the characteristics of this population such as range, diet, age, sex, sexual maturity status, size at sexual maturity, etc. Some of the squid we collect might also end up at outreach events like Gilly’s “Squids for Kids.” Tonight was an excellent night of squid fishing. With two glow-in-the-dark jigs in the water, we caught 29 D. gigas in about an hour. Their mantle lengths ranged from 30 centimeters (approximately one foot) to 52 centimeters (one and one-half feet), with the larger ones weighing in around four kilograms (almost nine pounds). Fishing is definitely my favorite method of collecting data!

— Ben Burford

Today we had another deep dive, reaching 2,000 meters (6,561 feet), searching for deep-living animals that we rarely get a chance to see. We also had the chance to collect some of our target animals, like Octopoteuthis deletron. Stephanie Bush is working with the Monterey Bay Aquarium to try to display these strange squid in a future exhibit there.

Upper left: Bruce Robison is working on describing the "Mystery Mollusc", which earned that name the first time the midwater lab observed it. They had no idea what kind of invertebrate it was. As it turns out, it’s closely related to sea slugs. Upper right: Octopoteuthis deletron is a squid, but has only eight arms. The arms also have glowing tips. Lower left: The hatchetfish, Sternoptyx obscura has light organs that produce light to help it blend into the ambient light that a predator below might see when looking up. Lower right: Halitrephes maasi is an uncommon jelly, seen less than a dozen times by MBARI ROVs in 25 years of operations.

Upper left: Bruce Robison is working on describing the “Mystery Mollusc”, which earned that name the first time the midwater lab observed it. They had no idea what kind of invertebrate it was. As it turns out, it’s closely related to sea slugs. Upper right: Octopoteuthis deletron is a squid, but has only eight arms. The arms also have glowing tips. Lower left: The hatchetfish, Sternoptyx obscura has light organs that produce light to help it blend into the ambient light that a predator below might see when looking up. Lower right: Halitrephes maasi is an uncommon jelly, seen less than a dozen times by MBARI ROVs in 25 years of operations.

—Susan von Thun