Humboldt Squid
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| Humboldt Squid | ||||||||||||||||
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 Humboldt Squid photographed
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| Dosidicus gigas (Orbigny, 1835) |
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The Humboldt Squid (Dosidicus gigas), also known as Jumbo Squid, Jumbo Flying Squid, or Diablo Rojo (Red Devil), is a large, aggressive predatory squid found in the waters of the Humboldt Current in the Eastern Pacific Ocean. They are most commonly found at depths of 200-700 metres (600 to 2300 feet), from Tierra del Fuego to California. Recent findings suggest the range of this species is spreading north into the waters of Oregon, Washington, British Columbia and Alaska.[1][2] Though they usually prefer deep water, between 1,000 and 1,500 squid washed up on the Long Beach Peninsula in southwest Washington in the fall of 2004.[3]
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[edit] Behavior and general characteristics
Humboldt Squid are carnivores that move in schools of up to 1200 individuals. They swim at speeds of up to 15 miles per hour (24 km/h, 13 knots) propelled by water ejected through a hyponome (siphon) and by two diamond shaped fins. Their tentacles bear suckers lined with sharp teeth with which they grasp prey and drag it towards a large, sharp beak.
Humboldt Squid are thought to have a lifespan of only about one year (although some researchers believe they may survive up to four years). They may grow to 2 m (7 ft) and weigh 45 kg (100 pounds), growing at an astounding rate. They can rapidly change their skin colour from deep purplish red to white using chromatophores (specialized skin cells) in what some researchers believe is a complex communication system. Experts have also stated that the animals hunt for their prey, small fish and krill, in a cooperative fashion, which would be the first observation of such behaviour in invertebrates.[4] Humboldt squid are known to hunt near the surface at night, taking advantage of the dark to use their keen vision to feed on more plentiful prey. There have been reports of these squid attacking divers and fishermen in the Sea of Cortez.[5]The shallowest depths Humboldt Squid's daytime habitat are only within reach of the extremes of Saturation diving, so little is known of what they do during the day.
Recent research suggests that the squids are only aggressive while feeding. At other times, they are quite passive. Their behavior while feeding often extends to cannibalism and they've been seen to readily attack injured or vulnerable squids of their own school. This behavior may account for a large proportion of their rapid growth.[6][7]
[edit] Body characteristics
Generally, the tube (or body) constitutes about 40% of the animal's mass, the fin (or wing) about 12%, the tentacles about 14%, the outer skin about 3%, the head (including eyes and beak) about 5%, with the balance (26%) made up of the inner organs. In circumstances where these animals are not being grossly over-fished, they exhibit very curious and intelligent behavior.[8]
Recent footage of pods of these animals demonstrates a tendency to meet unfamiliar objects aggressively. Having risen to depths of 400-600 feet below the surface to feed (up from their typical 2,000 foot diving depth, beyond the range of human diving), they have attacked deep-sea cameras and rendered them inoperable. Reports of recreational scuba divers being attacked by Humboldt Squid have been confirmed. One particular diver, Scott Cassell,[9] who has spent much of his career videotaping this species has developed body armor to protect against attacks.[10] Each of the squid's suckers is ringed with sharp teeth, and the beak itself can tear flesh, although it's believed they lack the jaw strength to crack heavy bone.[6] Nevertheless, they eat their prey by grabbing it with their tentacles and biting it repeatedly with their beak. Working together, several squid are able to devour large prey very quickly.
[edit] Fishing
Commercially, this species has been caught to serve the European community market (mainly Spain, Italy and France), Russia, China, Japan, South East Asian and increasingly North and South American markets.
The squid are fished at night, when it is easier to lure them with lights used by fishermen that make the plankton shine, which makes the squid rise to the surface to feed. Since the 1990s, the most important areas for landings of Humboldt Squid are northern Peru and Mexico.
There are numerous accounts of the squid attacking fishermen and divers in the area and attacks on humans are regularly seen, but only when they are being fished. Their colouring and aggressive reputation has earned them the nickname diablos rojos (red devils) from fishermen off the coast of Mexico as they flash red and white when struggling with the fishermen.
[edit] See also
[edit] References
- ^ Humboldt Squid Found in Pebble Beach (2003)
- ^ Invasive range expansion by the Humboldt squid, Dosidicus gigas, in the eastern North Pacific (2007)
- ^ Aggressive eating machines spotted on our coast (2008)
- ^ Behold the Humboldt squid. Tim Zimmermann, Outside Magazine, July 2006.
- ^ Sea of Cortez, 1995
- ^ a b The Curious Case of the Cannibal Squid, Michael Tennesen, National Wildlife Magazine, Dec/Jan 2005, vol. 43 no. 1.
- ^ Squid SensitivityDiscover Magazine April, 2003
- ^ Behold the Humboldt Squid | Outside Online
- ^ DeeperBlue.net - Fanatical About FreeDiving, Scuba Diving, Spearfishing & Technical Diving
- ^ Cassell, S. Dancing with Demons. Deeper Blue, 2005-12-15
