Skip to main content Accessibility help

The reproductive cycle of a deep-sea eel, Nettastoma melanurum (Nettastomatidae: Anguilliformes) from the south-eastern Sardinian Sea (central-western Mediterranean)

  • Cristina Porcu (a1), Maria Cristina Follesa (a1), Alice Gastoni (a1), Antonello Mulas (a1), Claudia Pedoni (a1) and Angelo Cau (a1)...


The reproductive cycle of the deep-sea eel Nettastoma melanurum was described based on 397 specimens (171 males and 226 females). Experimental trawl surveys between depths of 772 and 1598 m and commercial hauls (580–600 m) on compact mud bottoms off the south-eastern Sardinian waters (central-western Mediterranean) were carried out. The Sardinian catches did not indicate any particular trend of size-range in relation to depth in both sexes and seem to be sexually dimorphic with females growing almost 9 cm longer than males at maximum lengths. It was a dioeceous and an oviparous deep-sea species. For females and males, six stages of oocyte development, characterizing the different stages of maturity, were identified. Histological examination demonstrated that ovaries of N. melanurum showed a ‘group-synchronous’ pattern, highlighting a type of monocyclic ovary. The species showed a size at first maturity of 53.5 cm and 50.5 cm total length in females and males respectively. The reproductive period appeared to be unique and well defined in both sexes. Their monthly changes of gonadosomatic index and maturation phases of ovaries and testis showed that the species was in a resting period from March to July. Vitellogenesis and spawning began in September and ended in January. Nettastoma melanurum seemed to be a fecund species (8132–18755 eggs).


Corresponding author

Correspondence should be addressed to: C. Porcu, Dipartimento di Scienze della Vita e dell'Ambiente, Sezione di Biologia Animale ed Ecologia, University of Cagliari, Via T. Fiorelli n.1 09126, Cagliari, Italy email:


Hide All
Anderson, R.O. and Gutreuter, S.J. (1983) Length, mass, and associated structural indices. In Nielsen, L.A. and Johnson, D.L. (eds) Fisheries techniques. Bethesda, MD: American Fisheries Society, pp. 283300.
Başusta, N., Turan, C. and Gürlek, M. (2002) A new fish record from Turkish seas: the blackfin sorcerer Nettastoma melanurum Rafinesque, 1810 (Nettastomidae). Turkish Journal of Veterinary and Animal Sciences 26, 11851187.
Beebe, W. (1935) Deep-sea fishes of the Bermuda Oceanographic Expeditions. Family Derichthyidae. Zoologica 20, 123.
Ben Tuvia, A. (1971) Revised list of the Mediterranean fishes of Israel. Israel Journal of Zoology 20, 139.
Billard, R. (1986) Spermatogenesis and spermatology of some teleost fish species. Reproduction, Nutrition, Development 26, 877920.
Carrassón, M. and Cartes, J.E. (2002) Trophic relationships in a Mediterranean deep-sea fish-community: partition of food resources, dietary overlap and connections within the benthic boundary layer. Marine Ecology Progress Series 241, 4155.
Casadevall, M., Muñoz, M., Carrassón, M. and Matallanas, J. (2001) The reproductive cycle of Ophichthus rufus (Anguilliformes) in the northwest Mediterranean. Cybium 25, 5365.
D'Onghia, G., Politou, C.Y., Bozzano, A., Lloris, D., Rotllant, G., Sion, L. and Mastrototaro, F. (2004) Deep-water fish assemblages in the Mediterranean Sea. Scientia Marina 68, 8799.
Dagnélie, P. (1970) Théorie et méthodes statistiques. In Duculot, J. (ed.) Les méthodes de l'inférence statistique. Volume 2. Gembloux, Belgium: Les Presses Agronomiques, p. 171.
Fishelson, L. (1994) Comparative internal morphology of deep-sea eels, with particular emphasis on gonads and gut structure. Journal of Fish Biology 44, 75101.
Follesa, M.C., Porcu, C., Cabiddu, S., Davini, M.A., Sabatini, A. and Cau, A. (2007) First observations on the reproduction of Alepocephalus rostratus Risso, 1820 (Osteichthyes, Alepocephalidae) from the Sardinian Channel (Central-Western Mediterranean). Marine Ecology 28, 7581.
Follesa, M.C., Porcu, C., Cabiddu, S., Mulas, A., Deiana, A.M. and Cau, A. (2010) Deep-water fish assemblages in the central-western Mediterranean (south Sardinian deep-waters). Journal of Applied Ichthyology 27, 129135.
Follesa, M.C., Porcu, C., Mulas, A., Salvadori, S. and Cau, A. (2011) Reproductive characteristics of the bathyal viviparous fish Cataetyx alleni (Osteichthyes: Bythitidae) from the southeastern Sardinian Sea (central-western Mediterranean). Scientia Marina 75, 391397.
Gage, J.D. and Tyler, P.A. (1991) Deep-sea biology: a natural history of organisms at the deep-sea floor. Cambridge: Cambridge University Press.
Galil, B.S. and Goren, M. (1994) The deep sea Levantine fauna—new records and rare occurrences. Senckenbergiana Maritima 25, 4152.
Golani, D. (1996) The marine ichthyofauna of the eastern Levant: history, inventory and characterization. Israel Journal of Zoology 42, 1555.
Grier, H.J. (1981) Cellular organization of the testis and spermatogenesis in fishes. American Zoologist 21, 345357.
Hunter, J.R., Macewicz, B.J. and Kimbrell, C.A. (1989) Fecundity and other aspects of the reproduction of sablefish, Anoplopoma fimbria, in central California waters. California Cooperative Oceanic Fisheries Investigations Reports 30, 6172.
Hunter, J.R., Macewicz, B.J., Lo, N.C. and Kimbrell, C.A. (1992) Fecundity, spawning, and maturity of female Dover sole Microstomus pacificus, with an evaluation of assumptions and precision. Fishery Bulletin 90, 101128.
Hureau, J.C. (1991) La base de données GICIM: gestion informatisée des collections ichthyologiques du muséum. In Atlas préliminaire des poissons d'eau douce de France. Paris: Conseil Supérieur de la Pêche, Ministère de l'Environnement, CEMAGREF et Muséum national d'Histoire naturelle, pp. 225227.
Karmovskaya, E.S. and Merrett, N.R. (1998) Taxonomy of the deep-sea eel genus, Histiobranchus (Synaphobranchidae, Anguilliformes), with notes on the ecology of H. bathybius in the eastern North Atlantic. Journal of Fish Biology 53, 10151037.
Lombarte, A. and Cruz, A. (2007) Otolith size trends in marine fish communities from different depth strata. Journal of Fish Biology 71, 5376.
Mazzi, V. (1977) Tecniche istologiche e istochimiche. Padova: Piccin, 750 pp.
Mead, G.W., Bertelsen, E. and Cohen, D.M. (1964) Reproduction among deep-sea fishes. Deep-Sea Research 11, 569596.
Merrett, N.R. and Haedrich, R.L. (1997) Deep-sea demersal fish and fisheries. London: The Natural History Museum/Chapman and Hall.
Merrett, N.R. and Saldanha, L. (1985) Aspects of the morphology and ecology of some unusual deep-sea eels (Synaphobranchidae, Derichthyidae and Nettastomatidae) from the eastern North Atlantic. Journal of Fish Biology 27, 719747.
Merrett, N.R. (1994) Reproduction in the North Atlantic oceanic ichthyofauna and the relationship between fecundity and species' sizes. Environmental Biology of Fishes 41, 207245.
Miller, P.J. (1979) Adaptiveness and implications of small size in teleosts. Symposia of the Zoological Society of London 44, 263306.
Morales-Nin, B., Massuti, E. and Stefanescu, C. (1996) Distribution and biology of Alepocephalus rostratus from the Mediterranean Sea. Journal of Fish Biology 48, 10971112.
Moranta, J., Palmer, M., Massutí, E., Stefanescu, C. and Morales-Nin, B. (2004) Body fish size tendencies within and among species in the deep-sea of the western Mediterranean. Scientia Marina 68, 141152.
Morley, S.A., Mulvey, T., Dickson, J. and Belchier, M. (2004) The biology of the bigeye grenadier at South Georgia. Journal of Fish Biology 64, 15141529.
Murua, H. and Saborido-Rey, F. (2003) Female reproductive strategies of marine fish species of the North Atlantic. Journal of Northwest Atlantic Fishery Science 33, 2331.
Nelson, J.S. (2006) Fishes of the world. 4th edition. Hoboken, NJ: John Wiley & Sons, Inc, 601 pp.
Orton, J.H. (1920) Sea temperature, breeding and distribution in marine animals. Journal of the Marine Biological Association of the United Kingdom 12, 339366.
O'Sullivan, S., Moriarty, C., FitzGerald, R.D., Davenport, J. and Mulcahy, M.F. (2003) Age, growth and reproductive status of the European conger eel, Conger conger (L.) in Irish coastal waters. Fisheries Research 64, 5569.
Porcu, C., Follesa, M.C., Grazioli, E., Deiana, A.M. and Cau, A. (2010) Reproductive biology of a bathyal hermaphrodite fish, Bathypterois mediterraneus (Osteichthyes: Ipnopidae) from the south-eastern Sardinian Sea (central-western Mediterranean). Journal of the Marine Biological Association of the United Kingdom 90, 719728.
Rohlf, F.J. (2005) TpsDig, digitize landmarks and outlines, version 2.04. Department of Ecology and Evolution, State University of New York at Stony Brook.
Rotllant, G., Moranta, J., Massutí, E., Sardà, F. and Morales-Nin, B. (2002) Reproductive biology of three gadiform fish species through the Mediterranean deep-sea range (147–1850 m). Scientia Marina 66, 157166.
Saldanha, L. (1986) Nettastomatidae. In Whitehead, P.J.P., Bauchot, M.-L., Hureau, J.-C., Nielsen, J. and Tortonese, E. (eds) Fishes of the north-eastern Atlantic and the Mediterranean. Paris: UNESCO, pp. 562566.
Smith, D.G. and Castle, P.H.J. (1982) Larvae of the nettastomatid eels: systematics and distribution. Dana Report 90, 144.
Smith, D.G., Böhlke, J.E. and Castle, P.H.J. (1981) A revision of the nettastomatid eel genera Nettastoma and Nettenchelys (Pisces: Anguilliformes), with descriptions of six new species. Proceedings of the Biological Society of Washington 94, 535560.
Sokal, R.R. and Rohlf, F.J. (1995) Biometry: the principles and practice of statistics in biological research. 3rd edition. New York: W.H. Freeman and Co., 887 pp.
Spartà, A. (1942) Uova, stadi embrionali, prelarve e larve di Nettastoma melanurum Raf. Archivio di Oceanografia e Limnologia 2, 151158.
Takashima, F. and Hibiya, T. (1995) An atlas of fish histology: normal and pathological features. 2nd edition. Tokyo: Kodansha Ltd., 195 pp.
Ungaro, N., Marano, C.A., Marsan, R., Martino, M., Marzano, M., Strippoli, G. and Vlora, A. (1999) Analysis of demersal species assemblages from trawl surveys in the South Adriatic Sea. Aquatic Living Resources 12, 177185.
Wallace, R.A. and Selman, K. (1981) Cellular and dynamic aspects of oocyte growth in teleosts. American Zoologist 21, 325343.
Zar, J.H. (1999) Biostatistical analysis. 3rd edition. Englewood Cliffs, NJ: Prentice-Hall, 662 pp.



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed