18 May 2015

Ocean Giants: Giant Squid

Last week we talked about the Kraken, that it's a squid-like sea monster and that its identity can be either of the two known largest extant squids. First was the heaviest, the colossal squid Mesonychoteuthis hamiltoni (read article here). The second is the longest, the giant squid Architeuthis dux with a cosmopolitan distribution.

Photo taken by Tsunemi Kubodera from Ogasawara Islands, off Tokyo on December 4, 2006 [1].

There are many different species listed under the genus Architeuthis, 21 nominal species in total. But based on a genetic study conducted by Guerra et al (2013), all species are synonyms of A. dux; thus, there is only one giant squid. Furthermore, like the majority of deep sea species, little is known of its biology. Obviously it's a predator; it feeds on fishes and other cephalopods. It has a short life cycle; spawning occurs only once and the females die after bearing their eggs. The largest recorded species measured 12 m in length, unfortunately there was no record of its weight. Studies on its growth and mortality were very limited since getting a sample population from the ocean was tough. Thus, if you have other information on them, which you wish to include in our information system, please e-mail us at sealifebase@fin.ph or join us as a collaborator.

[1] Accessed from http://animals.nationalgeographic.com/animals/invertebrates/giant-squid/
[2] McClain CR et al (2015) Sizing ocean giants: patterns of intraspecific size variation in marine megafauna. PeerJ 2:e715. Accessed from https://peerj.com/articles/715/
[3] Guerra A et al (2013) Architeuthis dux: Ășnica especie de calamar gigante en el mundo. MOL. Revista de la Sociedad de Ciencias de Galicia 53:46-53.
[4] Bolstad KS et al (2004) Gut contents of a giant squid Architeuthis dux (Cephalopoda: Oegopsida) from New Zealand waters. New Zealand Journal of Zoology 31(1):15-21.

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