Age, growth and feeding habits of the brown comber Serranus hepatus (Linnaeus, 1758) on the Cretan shelf

Forty-five samples of the brown comber Serranus hepatus were collected during experimental surveys carried out on a monthly basis (August 1990 to August 1992) along the Cretan continental shelf. A total of 1268 specimens 31-140 mm in total length were analysed. Growth was well described by both standard and seasonalized forms of the von Bertalanffy growth model and the computed parameters were L infinity=152 mm, k=0.36, t(o)= -0.57. Feeding intensity was high throughout the study period and varied significantly among the age classes of fish examined. Stomach content analysis revealed that S. hepatus is carnivorous, feeding mainly on decapods. Diets did not vary seasonally; decapods were the most important prey throughout the year. However, the composition of the prey consumed varied considerably with predator age coupled with differences in mean prey sizes utilized by each age class. The mean weight of stomach contents increased significantly for older specimens, while the mean number of prey items decreased. Age-specific dietary selection was primarily a function of body size of the predator and appears to reduce intra-specific competition among the members of the different age classes. The results suggest that S. hepatus plays an important trophic role as a macrophagic carnivorous species on the Cretan continental shelf. (C) 1998 Academic Press Limited.