New records of the giant squid Architeuthis dux in the southern Indian Ocean

• Main Author: Yves Cherel
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Curl; Indian; Kerguelen; New Zealand; Roper; Saint-Paul; Union Island; Amsterdam Island; Newfoundland; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.566.890; http://www.cebc.cnrs.fr/publipdf/2003/CJMBAUK.pdf

Only one specimen of Architeuthis dux was previously reported from the southern Indian Ocean. The present work adds ten new records of giant squid in the area. Two remains of fresh specimens have been collected from La Re ¤ union Island (218S) and Amsterdam Island (388S) in tropical and subtropical waters, respectively. Eight other squid were identi¢ed from beaks found in stomach contents of sleeper sharks caught in Kerguelen waters (47 to 488S) located in the southern Polar Frontal Zone. These new data together with published and unpublished information on the food of seabirds and marine mammals indicate that giant squid have a wide distribution throughout the southern Indian Ocean. Most records of the giant squid (Architeuthis dux Steenstrup, 1857) come from some localities in the North Atlantic (Newfoundland, northern Europe), South Atlantic (South Africa), New Zealand and the North Paci¢c (Japan). It is thought to be a cosmopolitan species or a complex of species, but, in many parts of the world ocean, either no or a few specimens have been recorded (Clarke, 1966; Roper & Boss, 1982). In the Indian Ocean, except the occurrence of specimens in the diet of sperm whales caught o ¡ eastern South Africa and western Australia (Clarke, 1980), only one giant squid was found stranded on the small oceanic island of Saint Paul in 1874, the so-called A. sanctipauli Velain, 1875 (Species dubium; Fo « rch, 1998). In this note, we report two new observations of speci-mens at sea and the occurrence of beaks of giant squid in the diet of deep-sea sharks from di¡erent water masses of the southern Indian Ocean. Giant squid were identi¢ed from the morphology of their chitinous lower and upper beaks. Beaks of A. dux have a typical shape, the chitin is thin and lightly coloured, and often the wings and lateral walls curl up (Clarke, 1986). Lower beaks might be confused with those of Thysanoteuthis rhombus Troschel, 1857, but Architeuthis beaks grow to and darken at a larger size (Clarke, 1986). Lower rostrum length (LRL) was ...