Cephalopod prey of king penguins (Aptenodytes patagonicus) breeding at Volunteer Beach, Falkland Islands, during austral winter 1996

The beaks of 10 cephalopod species were found in the diet of foraging and m oulting king penguins (Aptenodytes patagonicus) from a breeding colony at V olunteer Beach, Falkland Islands during austral winter (September/October 1 996). A total of 486 lower cephalopod beaks were collected, identified and measured (LRL: lower rostral length). Six cephalopod families occurred in t he penguins' diet with Onychoteuthidae being the most abundant (256 lower b eaks) and represented by Moroteuthis ingens (168; LRL range 2.1-6.8 mm), Mo roteuthis knipovitchi (79; LRL range 1.9-5.5 mm), and Kondakovia longimana (9; LRL range 2.1-7.4 mm). Other families were Ommastrephidae (135) with Ma rtialia hyadesi (127; LRL range 2.6-8.7 mm, (Ilex argentinus (6; LRL range 5.0-6.0 mm), and Ommastrephes bartrami (2; LRL range 7.9-8.8 mm): Loliginid ae with Loligo gahi (60; LRL range 0.8-2.1 mm); Gonatidae with Gonatus anta rcticus (28; LRL range 1.3-3.3 mm); Neoteuthidae with Alluroteuthis antarct icus (4; LRL range 2.1-3.9 mm), and Histioteuthidae with Histioteuthis elta ninae (3; LRL range 3.3-3.4 mm). Allometric equations were used to relate l ower rostral beak length with cephalopod body size and mass, M. ingens was the dominating cephalopod prey in terms of numbers (n = 168), whereas M. hy adesi was most important in terms of biomass (63 682 g). The present study provides first information on the cephalopod prey of Falkland islands king penguins. The data suggest that penguins take squid at coastal islands slop e regions as well as in oceanic waters which demonstrates their ability to forage in a wide geographical area and to alternate between specific foragi ng sites. Possible competition with the commercial squid fishery off the Fa lkland Islands is discussed. (C) 2001 Elsevier Science B.V. All rights rese rved.