The largest squid ever found was pulled up by a vessel fishing for Patagonian toothfish in the Ross Sea off Antarctica in March. The sizable cephalopod, which was eating a toothfish hooked by the longline fishing gear, has been transferred to Te Papa, the National Museum of New Zealand, where it is being studied by Steve O'Shea, a world authority on squid.
The squid is only the 7th adult specimen of the colossal squid (Mesonychoteuthis) to have been caught, and by far the largest. Its total length (with tentacles) is 5.1metres, considerably less than the fabled giant squid (Architeuthis
dux), but it has a much larger body. With a mantle (body tube) length of 2.5m, this sub-mature female is much bigger than even the largest known giant squid, which has a mantle length of only 2.25m. Dr. O'Shea estimates from the size of
Mesonychoteuthis beaks found in sperm whale stomachs that the mature squid grow up to twice the size of this specimen.
Little is known about the biology of the colossal squid, despite being apparently common in the Southern Ocean (where it is one of the main prey items of sperm whales). Juveniles have been caught as far north as Tasmania, but the adult specimens were all caught in Antarctic waters. It was previously thought to be found only in deep water, but this specimen had followed its toothfish prey to surface waters. Toothfish are its only confirmed prey, and unlike the giant squid, which is thought to hang in the water waiting for its prey to pass by, the colossal squid has large, muscular fins and is believed to be an active hunter.
It has a formidable horny beak, far larger for its size than the beak of its cousin the giant squid, and short, muscular arms lined with fierce, toothed suckers, which leave deep scars in the skin of its predator, the sperm whale.
This accidental find of (probably) the largest invertebrate animal in the world demonstrates how little is known about the ecology of deep ocean environments. Many deep water squid species are only known from a single specimen accidentally caught in trawl nets- who knows what species are still to be discovered?