IntroductionThe dominant oceanic nektonic squid Ommastrephes bartramii (Lesueur, 1821) is very widely distributed throughout the subtropical and lower-laltitude temperate zones of both hemispheres of the world ocean (Nesis, 1987). Its role in structure and functioning of the oceanic ecosystems is important, and has been the subject of study for the last three decades. However, geographical differences between feeding and parasitological characteristics of this species have not been extensively studied. The feeding ecology and helminth fauna was studied in the North Pacific (Shevtsov 1972, Wormuth 1976, Naito et al. 1977, Bower & Margolis 1991, Sinclair 1991, Seki 1993, Nagasawa et al. 1998, Watanabe et al. 2004, Bower & Ichii 2005, Young 2005, Parry 2006, 2008, the North and South Atlantic (Gaevskaya & Nigmatullin 1976, Nigmatullin & Pinchukov 1976 1 , Gaevskaya et al. 1986, Lipinski & Linkowski 1988, Hernandez-Garsia 1995, Lordan 2001, Ivanovic & Brunetti 2004) and the Indian Ocean and Australian waters (Filippova 1974, Dunning 1998, but squids from the southeastern part of the Pacific Ocean have not been investigated. There are only very scanty and superficial data on food of this squid in the central and eastern parts of the South Pacific with food organisms identified to higher taxon level only (Polezhaev 1986, Alexeev 1994 and several preliminary brief publications (Gaevskaya et al. 1983, Nigmatullin et al. 1985. The goal of this paper is to describe the food and helminth compositions of neon flying squid in the subtropical open waters of the southeastern Pacific.
Material and methodsSquids used for this study were collected during 1981-1984 aboard AtlantNIRO research vessels at nightlighting drift stations in the south part of the eastern Pacific (Fig. 1). The squids were caught with hand jigs. The squid were immediately frozen after capture and examined for food and helminths 4-6 months later. Squid were analyzed with identification of dorsal mantle length (ML), absolute length (AL), sex, stage of maturity and stomach fullness (six-point scale by Zuev et al. 1985).
FeedingSquids used for the food composition study were collected in the area between 17-32°S and 79-95°W in April 1981, July and November-December 1982 and January 1984 ( Fig. 1). Stomach contents were studied on 60 squids of ML 160-392 mm including 40 squids with full stomachs (fullness degree 3-5). From the total squids, 56 were males of ML 160-392 mm and 4 were females of ML 166-240 mm. Crustacean food items were identified by eyes, mandibles, maxillipeds, thoracic limbs and chitinous integuments; cephalopods were determined by beaks, horny rings of suckers and hooks; heteropods were identified by radular hooks; whereas fishes were identified by otoliths, scales and bony elements (Zuev et al. 1985). The identification of fish remains was based on published description according to the main diagnostic traits of osteological elements of pelagic fishes of the southeastern Pacific (Topal 1988). Estimate of fish body size were made fr...