Widespread in the cold dark waters of the deepsea at 500-1500 m deep. It is still unknown how many species exist in the world. The species caught off Australia is probably restricted to the Southern Ocean. They are most often caught in Orange Roughy deepsea fishing trawls on seamounts off Tasmania and western Victoria (NSW, VIC, TAS, SA, WA).
Giant Squids reach 18m long and over 250 kg in weight. They are recognised by the small fin on the end of the body and the two long feeding tentacles, the ends of which are armed with large suckers each with a ring of sharp teeth. Colour in life is blood red but this skin is often scraped off during capture in fishing nets, exposing the white muscle underneath.
Ecology/Way of Life:
Giant Squids are the largest invertebrate animals in the world yet they have never been seen in their natural environment. There is still very little known of about these "monsters" of the deepsea. They control their buoyancy by having special pockets full of salty liquid (ammonium chloride) in their flesh. This liquid is less dense than seawater and helps the squid to "float" midwater. They are probably sluggish predators, which use their huge eyes (larger than whale eyes) to look for light given off by fish or squid. They would then shoot their two long feeding tentacles out to grab their prey. These tentacles can reach 10m long and are joined along their shafts by small suckers and corresponding bumps which zip the shafts together. This allows them to send these tentacles out like a long snapping claw. Giant Squids may hang vertically with the feeding tentacles below them. Their main predators are Sperm Whales that dive to great depths to hunt these squids using echolocation.
Giant Squids are probably solitary, rarely meeting other members of their species. Mating consists of the male using his penis to inject nails of sperm into the skin of the female (photo). She stores the sperm until she is ready to release her eggs. It is not known how she gets the sperm out of her skin in order to fertilise her eggs. Females release millions of eggs, probably as a large floating ball of see-through jelly.
Interaction with Humans/Threats:
Giant squids pose no threats to humans. They only occur in deep cold waters (>500 m) where humans would be crushed by the pressure. The ammonia liquid in their flesh makes them inedible for humans. They are rarely captured. However recent fisheries for deepsea fish such as Orange Roughy have lead to an increase in captures (>10 in the past 5 years off southern Australia).
Ellis, R. 1999. The Search for the Giant Squid. Penguin Books, New York. 322.
Norman, M.D. and A. Reid. 2000. A guide to the squid, cuttlefishes and octopuses of Australasia. Gould League/CSIRO Publishing, Melbourne. 96 pp.
Text by Mark Norman; photographs by David Paul.
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