Editor's Note: William Gilly, a professor of cell and developmental biology and marine and organismal biology at Stanford University, is traveling with a group of students on board the Don José in the Sea of Cortez. They will monitor and track Humboldt squid and sperm whales in their watery habitats. This is the group's fourth blog post.

SEA OF CORTEZ—"This evening we catch a dozen mighty Humboldt squid at a depth of 100 meters while numerous small Humboldts dart in and out of the light from our boat. What is different about tonight from last night, when we only caught only one large squid? A simple question, but one that requires a deep knowledge of the squid, their prey and predators, and local oceanography. In the end, there is no simple answer, and that insight is why we are here."   

…Our cephalopod-desperate professor is beginning to command an Ahab-like presence on the Don José. I imagine a parallel universe in which Gilly has had his middle finger ruthlessly consumed by the oversized beak of a 100-centimeter jumbo squid as it escaped his grasp, the lost finger replaced soon after with the re-shaped, dried gladius-tip of another Doscidicus gigas. I see him tap-tap tapping this phantom phalange on the boat's railing as he gazes out to sea, his monomaniacal mind focusing harder and harder on vengeance for this unspeakable act. The small squid which the other scientists catch at night he regards with disgust, a waste of the time and energy to be spent exclusively in search of the jumbo who branded him so. Gilly "insanity," however, recognizes that these small catches are necessary if he is to placate his crew and prevent outright mutiny. Yet there is no hiding the fixed look in his one good eye, the single unwavering purpose which consumes his soul, the haunted look on his sleepless visage. Each time the boat slows, his squid-finger twitches, and he coolly releases his jig-lure yet again into the depths of his awaiting fate.

A yell goes up from the aft deck. In the digestive afterward of the evening's hearty dinner, hoots and hollers go up as the fishing pole bends over nearly double, clutched by white-knuckled hands, the line disappearing into the rippled waters. A mangled head of once-cephalopod comes into view clinging lifelessly to the rising lure, escorted by three enormous Humboldt squid that flash red and white while devouring their hooked companion. The frenzy intensifies as each successive lure returns to the surface with a squid, until twelve slimy, big-eyed behemoths between 73 centimeters and 80 centimeters in mantle length lie on the back deck. Already, the processing line has been set in motion, with several students opening the mantles to sort reproductive organs, livers and stomachs for further analysis; another group recording size, sex, and maturity data for each cephalopod; and a last few students cleaning the hefty mantle steaks to freeze for future culinary experiments. We determine that the impressive biomass of a single Humboldt squid can be systematically dismantled by a team of marine scientists in less than five minutes.

Although most Humboldt squid pulled out of the water tonight are a deep maroon-red, one of our twelve jumbos is blanched an appalling white. This difference, while atypical, might be explained by a dissimilar stress reaction in the portion of the animal's brain that controls its chromatophores. These tiny muscular organs in the skin change body color as they turn on and off under neural control. As students admire this white anomaly, Gilly emerges from the cabin and glowers at the great white squid, intently surveying the triumph of the night. On his face I discern the faint blossom of a look, which, unlike that of Melville's captain, soon flowers out in a smile.

Image of squid jigging courtesy of Lauren Linsmayer; image of squid interior courtesy of Krista Doersch; image of white squid courtesy of Krista Doersch