Hybridization of Mediterranean groupers: Epinephelus marginatus ♀×E. aeneus ♂ and early development

Interspeci®c hybridization is a useful technique used in aquaculture to produce ®sh with desirable traits from two different species (Chevassus 1983).The results of hybridization are extremely variable, from non-viable embryonic development to viable and even fertile progenies (Varadi, Hidas, Varkonyi & Horvath 1995).Many interspeci®c hybrids have been produced, but most of them are of no applied importance (Hulata 1995).But, on the other hand, a signi®cant number of hybrids are suitable for aquaculture and have desirable characteristics from both parents (Issa, Horvath, Kosba & Sharrabi 1986;Kowtal 1987;Salami, Fagbenro & Sydenham 1993;Basaravaju, Devaraj & Ayyar 1995;Harrell 1998).This is accounted for by heterosis, which depends on two main complementary genetic mechanisms: the combination of useful dominant genes accumulated by both crossed forms and the increase in the total level of heterozygosity (Kirpichnikov 1981).Early investigations on the hybridization of Mediterranean sparid species (Jug Dujakovic  & Glamuzina 1990; 1993) led to the creation of a hybrid between Pagrus major (Temminck & Schlegel 1842) and Dentex dentex (Linnaeus 1758) and its successful commercial rearing in Sicily (La Cavera, Di Noto, Russo-Alesi & Cardamone 1998).Investigations into Mediterranean grouper rearing, compared with other parts of the world, are still Hybridization of Mediterranean groupers B Glamuzina et al.