386 



First record of a yellowfin tuna (Thunnus albacares) 

 from the stomach of a longnose lancetfish 

 (Alepisaurus ferox) 



Evgeny V. Romanov 



Southern Scientific Research Institute of Marine Fisheries and Oceanography 



(YugNIRO) 



2, Sverdlov St 



98300 Kerch 



Cnmea, Ul<raine 



E-mail address islandia'cnmea com 



Veniamin V. Zamorov 



Odessa National Universiry (ONU) 

 2, Dvoryanskaya St 

 65000, Odessa, Ukraine 



In 1987 we found a juvenile yellowfin 

 tuna, Thunnus albacares (Bonnaterre, 

 1788), in the stomach of a longnose lan- 

 cetfish, Alepisaurus fbrox Lowe, 1833. 

 Analysis of published information on 

 lancetfish food habits (Haedrich, 1964, 

 1969; Haedrich and Nielsen, 1966; 

 Parin, 1968; Parin et al., 1969; Four- 

 manoir, 1969; Grandperrin and Legand, 

 1970; Kubota and Uyeno, 1970; Legand 

 et al., 1972; Kubota, 1973; Fujita and 

 Hattori, 1976; Matthews et al., 1977) 

 led us to conclude that this was the first 

 record of a yellowfin tuna found in a 

 lancetfish stomach. 



Although this finding has been re- 

 corded in "gray literature" (Zamorov et 

 al.'; Zamorov and Romanov'-), the lim- 

 ited circulation of this type of litera- 

 ture, the fact that there were some in- 

 accuracies in the details of the record, 

 and the absence of similar findings in 

 recent studies (Okutani and Tsukada, 

 1988; Moteki et al, 1993), led us to 

 publish the finding with correct infor- 

 mation in the following note. 



Materials and methods 



A juvenile yellowfin tuna (Fig. 1) in 

 good condition was found in the stom- 

 ach of a lancetfish caught by pelagic 

 longline on 17 May 1987 during a 

 research cruise in the waters of the 

 exclusive economic zone of Mauritius, 

 western Indian Ocean. The longline 



set position was 9°32'S, 58°03'E. The 

 depth of hook, which caught the lan- 

 cetfish, was 99 m. 



Results and discussion 



The fork length (FL) of the lancetfish 

 was 167 cm, its weight was 9 kg; FL of 

 the yellowfin tuna was 37 cm and its 

 weight was 790 g. The tuna was imma- 

 ture and its stomach was empty The 

 tuna was 22.29; of the lancetfish body 

 length and 8.8% of its weight. The tuna 

 was found in the lancetfish stomach 

 with its tail towards the mouth of the 

 lancetfish. Evident transverse lateral 

 damage to the tuna body included long, 

 deep, open wounds and an absence of 

 skin and scales in the middle part of 

 the body. Deep wounds were absent 

 on the head and caudal part of the 

 tuna, where damage was minor (Fig. 

 2). Analysis of the photos allowed us to 

 hypothesize about the manner of cap- 

 ture. Presence of transverse damage to 

 the middle part of the body suggested 

 that the tuna was caught by the lan- 

 cetfish across the body and held until it 

 lost its ability to swim. The teeth of the 

 lancetfish had also caused cuts, likely 

 inflicted during the convulsive struggle 

 of the tuna to free itself The absence 

 of wounds in other parts of the tuna's 

 body, in particular on its head, indi- 

 cated that after the tuna became inac- 

 tive, it was released from the predator's 



teeth and swallowed head-first. The 

 proportions of the lancetfish mouth 

 and the victim allowed the tuna to be 

 swallowed whole. 



Longnose lancetfish is a common by- 

 catch species on tuna longlines in the 

 study area, the northern stream of the 

 South Equatorial Current, during the 

 sui-vey (April-June 1987 ) and are caught 

 regulau-Iy at depths of 60-120 m. We 

 have found slow-swimming animals in 

 the stomachs of lancetfish ( Zamorov et 

 al.'; Zamorov and Romanov-; Romanov 

 and Zamorov'). The diet of lancetfish 

 consists of pelagic crustaceans ( Hyperi- 

 idae, Portunidae, Amphipoda), cephalo- 

 pods of the families Onychoteuthidae, 

 some Ommastrephidae (Ornithoteuthis 

 volatilis), Cirroteuthidae, Octopodidae, 

 Argonautidae, Cranchiidae, Histioteu- 

 thidae, Bathyteuthidae, and mesopelag- 

 ic fishes (Sternoptyx diaphana. Parale- 

 pis elongata. Omosudis lowei, A. ferox, 

 Antigonia rubescens, Tylerius spinosis- 

 simus) (Haedrich and Nielsen, 1966; Pa- 

 rin et al., 1969; Fourmanoir, 1969; Kubo- 

 ta and Uyeno, 1970; Rancurel, 1970; 

 Fujita anci Hattori, 1976; Matthews et 

 al, 1977; Moteki et al., 1993). These are 

 slow-swimming species."* 



' Zamorov V. V., A. M. Amelekhina, and 

 A. A. Rybalko. 1992. On the feeding of 

 Alepisaurus ferox Lowe, 1833 in the west- 

 ern Indian Ocean. In Fauna and ecology 

 of animals. Proc. Zool. Mus. Odessa 

 State Univ. 1, p. 23-37. Odessa National 

 Univ. (ONU), 2, Dvoryanskaya St., 65000 

 Odessa, Ukraine. [In Russian.] 



- Zamorov, V. V., and E. V. Romanov. 1993. 

 New data on feeding of lancetfish Alepis- 

 aurus ferox Lowe, 1833. //; Resources of 

 tunas and related species in the World 

 Ocean and problems of their rational uti- 

 lization, p. 115-116. (Abstracts of the 

 reports presented at first interstate confer- 

 ence "Resources of tunas and related spe- 

 cies in the World Ocean and problems of 

 their rational utilization." Kerch 1-5 June 

 19921. YugNIRO, Kerch, |In Russian.] 



' Romanov, E. V., and V. V. Zamorov, 2002, 

 Feeding habits of longnose lancetfish tA/fp(- 

 saurus ferox Lowe. 1833) in the western 

 Indian Ocean. Manuscript in preparation. 



^ However, small specimens of the fast- 

 swimming ommastrephid sqmdSthenoteu- 

 tins oualaniensis (Lesson, 18301 (mantle 

 length <10 cm) have been found in the 

 stomachs of lancetfish; the schooling life 

 and common behavior of squids, including 

 periods of slow swimming or passive drift, 

 make them vulnerable to this predator. 



Manuscript accepted 13 April 2001. 

 Fish, Bull 100(21:386-389 (2002). 



