Multispecies ichthyoplankton associations in epipelagic species: is there any intrinsic adaptive function?

Species composition, distribution patterns and abundance of larvae of epipe lagic fishes during June 1995 and June 1996, are described in waters of the northeastern Aegean Sea (eastern Mediterranean). Significant interannual d ifferences were found that appeared to be associated with differences in en vironmental conditions. In June 1996 waters were colder, less saline and ri cher in zooplankton, which indicated a delay in the spring-to-summer transi tion during that year. Concurrently, larvae of the small-sized anchovy (Eng raulis encrasicolus) were significantly more abundant in 1996 than in 1995. This contrasted with larvae of the middle-sized pelagics: Sardinella aurit a, Trachurus mediterraneus, Scomber japonicus and Auxis rochei, which were most abundant in 1995. These results indicate differences in reproductive s trategies among pelagic fishes, which we discuss in terms of 'income' versu s 'capital' breeding, as well as inter-specific differences in the performa nce abilities of the larvae. The multispecies larval association of middle- sized pelagics may be adaptive and result from similar responses among spec ies to the pelagic environment.