Estudi de l’estratègia alimentària del sarg, Diplodus sargus (F. Sparidae, Pisces)

Abstract

White seabream, Diplodus sargus, is a species of Sparid that exists in the Mediterranean sea and habits the rocky infralittoral and the Posidonia oceanica seagrass. In the past 10 years, there have been reported an increase of strange specimens: they became hard after cooking, and make them non eatable. That has never been seen on any other species of Diplodus. Despite the caulerpin has been described as the cause (which is a toxic invasive algae Caulerpa cylindracea (before called Caulerpa racemosa var. cylindracea)), this hypothesis may not be applied to the catalan coast, because there are no important reports of the algae’s emergence. In the current study, we have examined the stomach and intestinal content of 26 white seabreams of different sizes in order to disprove this hypothesis and so we can consider new hypothesis to describe what causes that anomaly. The results of the feeding study match the current literature: white seabream is a not specialist fish, and has an omnivorous and strongly varied diet which depends on different factors like the seasonality or the geographical area. It has been determined what animal preys and what ingested plants show more frequency and abundance in the diet. The most habitual species can’t be the observed anomaly’s cause, because nor animal preys or none of the habitual ingested plants have toxicity. Attending to the distribution analysis of the captured specimens which show the problem, we formulate diverse hypothesis of other possible causes, related with the species’ feeding strategy, but not with the particular foods