Squid Surprise

August 2010

Deep sea creature caught in Moreton Bay

I caught this squid in Moreton Bay in 2 feet of water. I have never seen it before. Is it a new species?

Answer

Your squid is a Diamondback Squid, Thysanoteuthis rhombus. This squid is found in warm tropical and subtropical oceans, including the Mediterranean Sea. In fact, it was first described in 1857 from a specimen caught in the Strait of Messina between Italy and the island of Sicily. In Australia it occurs from the top half of the continent down as far as southern Queensland.

The mantle length (the wide, flat part of the animal without the tentacles and arms) can be as long as 1 metre, but generally ranges from 50 - 60cm. Weight can range from 10 - 20kg. This specimen weighed 16.4kg and measured about 80 - 90cm long and 30cm across. Despite the large size of these animals, they have a short life span of about a year, becoming mature adults at 6 -8 months of age.

Photo of a Diamondback Squid Diamondback Squid, Thysanoteuthis rhombus

During the day it is generally found in moderately deep water (to 500 metres), but at night it often moves into shallower waters to feed. They are very strong swimmers and have been known to propel themselves out of the water and ‘fly’ several metres, sometimes landing on the decks of boats.

Further information:

http://tolweb.org/Thysanoteuthis_rhombus

http://plankt.oxfordjournals.org/cgi/reprint/24/4/333

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