NOTE Carpentieri et al.: Feeding habits of Merlucaus merluccius in the central Mediterranean Sea 



415 



mean weight of prey and decreasing mean number of 

 prey items per stomach. The shift towards large fish 

 prey (i.e., Centracanthidae) usually occurs slightly be- 

 fore maturity — the life history stage with much higher 

 energetic demands due to gonad development (Ross, 

 1978). A similar pattern was observed for Atlantic cod 

 (Gadus morhua) where sexual maturation and spawn- 

 ing are also associated with an ontogenetic change in 

 diet (Paz et al., 1993). Thus, increased energy demands 

 related to sexual requirements, gonad development, and 

 breeding activity appear to be the critical factors driv- 

 ing the changes in feeding strategy of M. merluccius. 



In large hakes (>36 cm), cannibalism played an 

 important role and should be carefully considered in 

 stock-recruitment analyses. Studies carried out in the 

 Mediterranean (Macpherson, 1977; Bozzano et al., 1997) 

 and in the Atlantic (Guichet, 1995; Link and Garrison, 

 2002) showed that cannibalism has some importance 

 for hake. In silver hake (M. bilinearis), cannibalism 

 notably increased with ontogeny (Link and Garrison, 

 2002). In the large cape hakes, M. capensis, hake is 

 the dominant food item (50% of the diet) for individu- 

 als larger than 60 cm (Roel and Macpherson, 1988). 

 Conversely, a low cannibalism rate was observed for 

 M. paradoxus in the same area (Payne et al., 1987). 

 This could be a response to the greater accessibility 

 of conspecifics compared to other species. As Payne et 

 al. (1987) pointed out, small hake are not found in the 

 vicinity of adults of the species. This is supported by 

 the observed size segregation by depth, which is more 

 pronounced in M. paradoxus than in M. capensis (Gor- 

 doa and Duarte, 1991). Density-dependent cannibalism 

 may be an important source of natural mortality that 

 can stabilize fish populations (Smith and Reay, 1991), 

 and for M. capensis, cannibalism has even been consid- 

 ered the main cause of natural mortality (Lleonart et 

 al., 1985; Payne and Punt, 1985). 



Our results on the trophic ecology of hake are of pri- 

 mary importance for future management of fish assem- 

 blages where this species plays an important predatory 

 role. Multispecies management requires quantitative 

 data on fish diet to elucidate the relationships between 

 species and, consequently, to forecast temporal biomass 

 fluctuations, under specific fishing regimes, in an inte- 

 grated manner. 



Literature cited 



Abella, A., J. F. Caddy, and F. Serena. 



1997. Do natural mortality and availability decline with 

 age? An alternative yield paradigm for juvenile fisheries, 

 illustrated by the hake Merluccius merluccius fishery in 

 the Mediterranean. Aquat. Living. Resour. 10:1-14. 

 Aldebert, Y., L. Recasens, and J. Lleonart. 



1993. Analysis of gear interaction in a hake fishery: the 

 case of the Gulf of Lions (NW Mediterranean). Sci. 

 Mar. 57:207-217. 

 Alheit, J., and T. J. Pitcher (eds.l. 



1995. Hake: fisheries, ecology and markets, 478 p. Chap- 

 man and Hall, London. 



Alvarez, P., L. Motos, A. Uriarte, and J. Egana. 



2001. Spatial and temporal distribution of European 

 hake. Merluccius merluccius (L.), eggs and larvae in 

 relation to hydro-biological conditions in the Bay of 

 Biscay. Fish. Res. 50:11-128. 

 Andaloro, F., P. Arena, and S. Prestipino Giarritta. 



1985. Contribution to the knowledge of the age, growth 

 and feeding of hake Merluccius merluccius (L. 1758) in 

 the Sicilian channel. FAO Fish Rep. 336:93-97. 

 Ardizzone, G. D., and F. Corsi. 



1997. Atlas of Italian demersal fishery resources. Biol. 

 Mar. Medit. 4(2), 568 p. 

 Arneri, E., and B. Morales-Nin. 



2000. Aspects of the early life history of European hake 

 from the central Adriatic. J. Fish. Biol. 53:1155- 

 1168. 

 Beamish, F. W. H. 



1966. Vertical migration of demersal fish in the northwest 

 Atlantic. J. Fish. Res. Board Can. 23: 109-139. 

 Bouaziz, A.. F. Djabali, and C. Maurin. 



1990. Regime alimentaire du merlu {Merluccius merluc- 

 cius, L., 1758) en baie de Bou Ismail. Rapp. Comm. 

 int. Mer Medit. 32(1) :273. 

 Bowman, R. E., and E. W. Bowman. 



1980. Diurnal variation in the feeding intensity and catch- 

 ability of the silver hake (Merluccius bilinearis). Can. 

 J. Fish. Aquat. Sci. 37:1562-1572. 

 Bozzano, A., L. Recasens, and P. Sartor. 



1997. Diet of the European hake Merluccius merluccius 

 (Pisces: Merlucciidae) in the Western Mediterranean 

 (Gulf of Lions). Mar. Sci. 61(11:1-8. 

 Buchholz, F, C. Buchholz, J. Reppin, and J. Fischer. 



1995. Diel vertical migration of Meganyctiphanes nor- 

 vegica in the Kattegat: comparison of net catches 

 and measurements with acoustic Doppler current pro- 

 filers. Helgol. Wiss. Meeresunters 49:849-866. 

 Casanova, B. 



1970. Repartition bathymetrique des euphausiaces dans 

 le bassin occidental de la Mediterranee. Rev. Trav. 

 Inst. Peches Marit. 34(2):205-219. 



Clarke, K. R., and R. M. Warwick. 



1994. Change in marine communities: an approach to 

 statistical analysis and interpretation, 144 p. Natural 

 Environment Research Council, UK. 

 Colloca, F., A. Belluscio, and G. D. Ardizzone. 



2000. Sforzo di pesca, cattura e gestione dello stock di 

 nasello (Meluccius merluccius) in un'area del tirreno 

 centrale. Biol. Mar. Medit. 7(1):117-129. 

 Colloca, F., P. Gentiloni, A. Belluscio, P. Carpentieri, and 

 G. D. Ardizzone. 



2002. Estimating growth parameters of the European 

 hake [Merluccius merluccius) through the analysis and 

 validation of annual increments in otoliths. Arch. Fish. 

 Mar. Res. 50 (21:174-179. 

 Fisher, W., W. M. Bauchot, and M. Schneider. 



1987. Fiches FAO d'identification pour les besoins de la 

 peche revision 1. Mediterranee et mer Noire. Zone de 

 peche 37, vol. 2: Vertebres, p. 761-1530. FAO, Rome. 

 Flamigni, C. 



1984. Preliminary utilization of trawl survey data for 

 hake {Merluccius merluccius. L.) population dynamics 

 in the Adriatic Sea. FAO Fish. Rep. 290:109-115. 

 Franqueville, C. 



1971. Macroplancton profond (invertebres) de la Mediter- 

 ranee nord-occidentale. Tethys 3(l):ll-56. 



