The Humboldt squid (Dosidicus gigas), also known as the red devil, jumbo squid, or jumbo flying squid, is a large, predatory squid living in the eastern Pacific Ocean. It is the only known species of the genus Dosidicus of the subfamily Ommastrephinae, family Ommastrephidae. Humboldt squid typically reach a mantle length of 1.5 m (5 ft), making the species the largest member of its family, and one of the largest species of squid. They are most commonly found at depths of 200 to 700 m (660 to 2,300 ft), from Tierra del Fuego to California. This species is currently spreading north into the waters of the Pacific Northwest, in Oregon, Washington, British Columbia, and Alaska. Like other members of the subfamily Ommastrephinae, they possess chromatophores which enable them to quickly change body coloration, known as 'metachrosis' which is the rapid flash of their skin from red to white. They have a relatively short lifespan of just 1–2 years. This species is the most important squid worldwide for commercial fisheries, with the catch predominantly landed in Chile, Peru and Mexico; however, a 2015 warming waters fishery collapse in the Gulf of California remains unrecovered. They have a reputation for aggression toward humans, although this behavior may only occur during feeding times.
Nomenclature
Common name This species is most often known as jumbo squid in English, but has also been called jumbo flying squid or Humboldt squid, with the last name most popular in naturalist sources. The name Humboldt refers to the Humboldt Current, off the southwestern coast of South America, where it was first collected. A general name for this species in Spanish in Latin America is calamar gigante. Local names for it are jibia in Chile or pota in Peru. They notably rapidly flash red and white when captured, earning them the nickname diablo rojo (meaning 'red devil') among local fishermen in Baja California, Mexico.
Taxonomy The existence of this creature was first reported to the scientific world by the Chilean priest and polymath Juan Ignacio Molina in 1782, who called it Sepia tunicata, Sepia being the type genus of cuttlefish. It was subsequently formally described as a species new to science by the French naturalist Alcide d'Orbigny, who named it Ommastrephes gigas in 1835, but an illustration was labeled Loligo gigas. Another French naturalist, Claude Gay, obtained some specimens from Chile and sent them to the Muséum national d'Histoire naturelle in Paris, where it was determined that the species did not belong in the genus Loligo either. In 1857 the Danish zoologist Japetus Steenstrup proposed the new genus Dosidicus to house the species, where it remains. The German zoologist George Pfeffer synonymized D. eschrichtii with D. gigas in 1912. The fossil species Dosidicus lomita is represented by fossils of statoliths from the Pliocene Lomita Marl of California, marking the earliest known occurrence of the genus.
Description
The Humboldt squid is the largest of the Ommastrephid squids, as some individuals may grow to 1.5 m (5 ft) in mantle length and weigh up to 50 kg (110 lb). They appear to be sexually dimorphic: on average the females mature at larger sizes than the males. Generally, the mantle (or body, which includes the fins or wings) constitutes about 56–62% of the animal's mass, the arms and tentacles about 11–15%, the head (including eyes and beak) about 10–13%, the outer skin (cuticle) 2.5–5.0%, the hepatopancreas (liver analogue) 4.2–5.6%, with the rest made up of the other inner organs. The gonads consist of 1.5–15.0% of the total mass. The gladius (the single inner 'bone') is 0.7–1.0%. Precise ratios depend on the age, sex and sizes of the individual squid.
They are propelled by water ejected through a hyponome (siphon) and by two triangular fins. The Humboldt's two tentacles are elastic and can lash out with remarkable speed to grab hold of prey, holding it fast with the help of a wealth of suckers on each tentacle. Each sucker includes an inner ring of teeth. After grabbing the prey, the tentacles then retract and the prey is drawn toward a large, razor-sharp beak.
Behavior
Humboldt squid are carnivorous marine invertebrates that move in shoals of up to 1,200 individuals. They swim at speeds up to 24 km/h (15 mph; 13 kn). Electronic tagging has shown Humboldt squid undergo diel vertical migrations, which bring them closer to the surface from dusk to dawn. Humboldt squid are thought to have a lifespan of about a year, although larger individuals may survive up to 2 years. Crittercams attached to two or three Humboldt squid revealed the species has two modes of color-generating (chromogenic) behavior:
The entire body flashes between the colors red and white at 2–4 Hz when in the presence of other squid, this behavior likely representing intraspecific signaling. This flashing can be modulated in frequency, amplitude and in phase synchronization with each other. What they are communicating to each other is unknown – it could be an invitation for sex or a warning to not get too close. The other chromogenic mode is a much slower "flickering" of red and white waves which travel up and down the body, this is thought to be a dynamic type of camouflage which mimics the undulating pattern of sunlight filtering through the water, like sunlight on the bottom of a swimming pool. The squid appear to be able to control this to some degree, pausing or stopping it. Although these two chromogenic modes are not known in other squid species, other species do have functionally similar behaviors.
Distribution and habitat
The Humboldt squid lives at depths of 200 to 700 m (660 to 2,300 ft) in the eastern Pacific (Notably in Chile and Peru), ranging from Tierra del Fuego north to California. Recently, the squid have been found as far north as British Columbia. They have also ventured into Puget Sound. Although they usually prefer deeper water, between 1,000 and 1,500 squid washed up on the Long Beach Peninsula in southwest Washington in late 2004 and red algae were a speculated cause for the late 2012 beaching of an unspecified number of juvenile squid (average length 50 cm or 1.5 ft) at Monterey Bay over a 2-month period.
Changes in distribution
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