GROWTH AND FEEDING IN THE SURF ZONES OF THREE SANDY BEACHES OF THE GULF OF CADIZ OF THE SPOTTED SEABASS, Dicentrarchus punctatus (BLOCH, 1792) AND THE EUROPEAN SEABASS, Dicentrachus labrax (LINNEAUS, 1758)

Zusammenfassung

Sandy beaches are used as nursery grounds by juvenile fish due to the availability of food and better shelter conditions. The aim of this study was to analyse in three beaches of the coast of Cádiz the growth and feeding habits in the surf zone of two species of commercial interest: the spotted seabass (Dicentrarchus punctatus) and the european seabass (Dicentrarchus labrax). Monthly samplings were conducted with a beach seine netduring dawn and dusk tides, taking environmental data at each of them. Growth and feeding habits were analyzed using otoliths and stomach contents, respectively. The size range of the individuals was between 3.8-31.5 cm for spotted seabass and 14.4-37.9 cm for european seabass, with age 0+ being the most frequent in both species. Length-weight relationship analysis determined negative allometric growth for spotted seabass (b=2.9383) and positive allometric growth for european seabass (b=3.1161) with an R2=0.99 for both species. Von Bertalanffy parameters were L∞=82.202, k=0.072, t0=-2.696 and L∞=91.519, k=0.093, t0=-2.287 for spotted seabass and european seabass, respectively. The length-weight relationship as well as the Von Bertalanffy model obtained for both species were similar to those reported by other authors, although there are some fluctuations conditioned by latitudinal differences. Regarding food habits, crustaceans and fish were the resources with the highest relative importance in both species. Differences in feeding habits were observed according to the time of the year and age class, but not according to the sex of the individuals.