147 



New information from fish diets on the importance 



of glassy flying squid iHyaloteuthis pelagica) 



(Teuthoidea: Ommastrephidae) 



In the epipelagic cephalopod community 



of the tropical Atlantic Ocean 



Yves Cherel (contact author)^ 



Richard Sabatie^ 



Michel Potier^ 



Francis Marsac^ 



Frederic Menard* 



' Centre d'Etudes Biologlques de Chize 

 UPR 1934 du Centre National de la Recherche Scientifique BP 14 

 79360 Villiers-en-Bois, France 

 Email address for Y Cherel cherel@cebc.cnrs.fr 



^ Pole Halieutique 

 Laboratoire d'Ecologie Halieutique, Agrocampus-Rennes 

 65 rue de Saint Brieuc 

 35042 Rennes Cedex, France 



3 Institut de Recherche pour le Developpement 

 Centre de La Reunion 

 UR 109 Thetis, BP 172 

 97492 Sainte Clotilde Cedex, Isle de La Reunion, France 



■* Institut de Recherche pour le Developpement 

 Centre de Recherche Halieutique Mediterraneenne et Tropicale 

 UR 109 Thetis, BP 171 

 34203 Sete Cedex, France 



Squids of the family Ommastrephi- 

 dae are a vital part of marine food 

 webs and support major fisheries 

 around the world. They are widely 

 distributed in the open ocean, where 

 they are among the most abundant 

 in number and biomass of nektonic 

 epipelagic organisms. In turn, seven 

 of the 11 genera of this family (Dosi- 

 dicus. Illex, Martialia, Nototodariis. 

 Ommastrephes, Sthenoteuthis, and 

 Todarodes) are heavily preyed upon 

 by top marine predators, i.e., birds, 

 mammals, and fish, and currently 

 support fisheries in both neritic and 

 oceanic waters (Roper and Sweeney, 

 1984; Rodhouse, 1997). Their com- 

 mercial importance has made the 

 large ommastrephids the target of 

 many scientific investigations and 

 their biology is consequently reason- 

 ably well-known (NigmatuUin et al., 

 2001; Zuyev et al., 2002; Bower and 

 Ichii, 2005). In contrast, much less 



information is available on the biol- 

 ogy and ecological role of the smaller, 

 unexploited species of ommastrephids 

 (e.g., Eucleoteuthis, Hyaloteuthis, 

 Ornithoteuthis, and Todaropsis). 



Hyaloteuthis pelagica (Bosc, 

 1802), the glassy flying squid, is the 

 smallest ommastrephid, reaching a 

 maximum mantle length of 90 mm 

 (Nesis, 1987). It appears to be an 

 epipelagic species that is probably 

 distributed in all tropical and sub- 

 tropical oceans (Nesis and Nigmatul- 

 lin, 1979; Wormuth, 1998). Hyaloteu- 

 this pelagica is rarely captured, but 

 was caught in large numbers during 

 a cruise off Brazil, where it was the 

 dominant ommastrephid captured 

 in nets ( Warneke-Cremer, 1986). 

 Almost nothing is known about its 

 trophic relationships, either as prey 

 or predator (Nesis and NigmatuUin, 

 1979). Numerous remains of//, pe- 

 lagica — from a few intact squids to 



a fairly large number of accumulated 

 beaks — were found in the stomachs 

 of large predatory fishes during re- 

 search cruises in the central Atlan- 

 tic Ocean in autumn 2000. In this 

 note, we describe the importance of 

 H. pelagica in fish diets, thus add- 

 ing new information about the abun- 

 dance and trophic role of a poorly 

 known ommastrephid species. 



Materials and methods 



Fieldwork was carried out in the 

 central Atlantic Ocean during three 

 cruises of the Japanese RV Shoyo 

 Maru in October-December 2000 

 (Fig. 1). Cruise I took place in tem- 

 perate waters of the north equato- 

 rial current (between 8-21°N and 

 42-29°W) and cruises II and III 

 took place in tropical waters of the 

 south equatorial divergence (between 

 2N-10°S and 13-26°W, and between 

 7-9°S and 9-24°W). Cruises were a 

 part of the Bigeye Tuna Year Pro- 

 gram (BETYP) that was undertaken 

 under the auspices of the Interna- 

 tional Commission for the Conserva- 

 tion of Atlantic Tunas (ICCAT). The 

 purpose of the cruises was to tag live 

 tunas caught by longlines in order to 

 investigate their migration pattern 

 and behavior in relation to fish aggre- 

 gating devices. 



Fish were measured (eye-fork length 

 for billfishes and fork length for other 

 species) and dissected onboard. In 

 the laboratory, each fish stomach 

 was thawed, opened, and both accu- 

 mulated (cephalopod beaks with no 

 flesh attached) and fresh items were 

 sorted. Fresh remains were divided 

 into broad prey classes (fish, cepha- 

 lopods, crustaceans, and others), and 

 weighed to calculate their proportion 

 by mass in the diet. Identification of 

 cephalopod prey relied on the exter- 

 nal morphological features of either 

 intact specimens or beaks. Beaks 



Manuscript submitted 2 March 2006 

 to the Scientific Editor's Office. 



Manuscript approved for publication 

 24 May 2006 by the Scientific Editor. 



Fish. Bull. 105:147-152 (2007). 



