templet

Monday 2 September 2013

squid humblodt



Humboldt or Jumbo Squid


Dosidicus gigas






 
Habitat
Humboldt squid live at depths of 660 to 2,300 feet in the eastern Pacific, ranging from Tierra del Fuego north to California. They take their name from the Humboldt Current in which they live off the coast of South America. Recently, the squid have been appearing further north, as far as Sitka, Alaska, raising alarm about ecological problems possibly underlying the northward migration. Some oceanographers suggest that warming oceans are at fault, while others speculate that declining numbers of the squid's predators due to overfishing may have allowed Humboldts to expand their range.
Physical description
Jumbo squid can reach up to six feet and weigh as much as 100 pounds. Their skin varies from deep purplish-red to white. Like other cephalopods, muscle-bound chromatophores on their skin enable them to flash a range of colors. They have two diamond-shaped fins which they use to swim and glide.
Lifespan
The average life span of a Humboldt squid is about one year.
Predators
Sperm whales, sharks, seals, swordfish, and marlin feed on Humboldt squid of all sizes, while gulls and large fish often capture juveniles.
Prey
Schools of squid surface at night to hunt lanternfish, shrimp, mollusks, and other cephalopods. They are also known to cannibalize other jumbo squid that have been maimed or captured in nets. The squid use the sharp, barbed suckers on their feeding tentacles to pierce the flesh of prey and drag it to their mouths where a fierce, baseball-sized beak tears it to shreds.
Jumbo squid are notoriously aggressive and have earned the nickname diablos rojos, or “red devilsâ€� from Mexican shrimpers, who fish them in the off-season. Fishermen exploit the Humboldts' affinity for lanternfish by using lights as fishing lures. The squid may attack divers when threatened and will continue to put up a fight even after they've been caught, blasting their captors with water and ink.
Behavior
Humboldt squid hunt in schools containing as many as 1,200 individuals. They swim at speeds from three to 15 miles an hour and can eject themselves from the water and glide through the air to escape predators. 
The squid undergo mass migrations in these groups for the purposes of feeding and spawning. In the spring, thousands of individuals race north to the Gulf of California. Recently, hundreds of dead Homboldts have washed ashore on beaches in Orange County. Oceanographers suspect environmental causes are to blame.
Reproduction
Experts know little about how jumbo squid spawn, in large part because the squid spend most of their lives at depths unsafe for diving. Their eggs have never been observed in nature. Like most cephalopods, Humboldt squid reproduce only once in their lifetime.
Status
Humboldt's are heavily fished off the coast of Mexico, but because ecologists know little about the size of their population, it has yet to be determined whether this practice is sustainable. Because of a dearth of information regarding squid, none are protected by CITES or the IUCN Red List.
Did you know...
Squid-like cephalopods are often referred to as Teuthids. The giant squid is called Architeuthis meaning “ruling squid.â€�These mysterious deep-sea creatures are the world's largest invertebrates, measuring 35 to 60 feet in length. Although a number of their monstrous carcasses have washed ashore or been discovered in the stomach's of whales, only one has been seen alive, in September 2004.

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