Seasonal Variation in Feeding Patterns and Food Niche Overlap in the Mediterranean Blennies Scartella cristata, Parablennius pilicornis and Lipophrys trigloides (Pisces: Blenniidae)

Abstract. Gut contents of a total of 180 specimens of the blennies Scartella cristata (L., 1758). Parablennius pilicornis (C uvier , 1829) and Lipophrys trigloides (V alenciennes , 1836) caught in the course of 1990 off Playa de la Mora (Prov. Tarragona, Spain) were analysed. The quantitative composition of food differed considerably between the 3 species (mostly algae in the herbivorous S. cristara. Amphipoda in the carnivorous L. trigloides and a variety of items in omnivorous P. pilicornis ). The 3 species in the course of a year overlap little in food resource use, with overlap reaching its maximum in April when juvenile Mytilus on the rock substrate are in ample supply. In S. cristata and L. trigloides , diversity of food items is similarly lowest in July and April, respectively, when these 2 species attain their optimal nutritional status. In contrast, diet diversity and food intake are inversely correlated in P. pilicornis. Evidently, resource sharing between blenniid species in the rocky shore habitat is clearly structured, but subject to seasonal dynamics. It is concluded that food niche analyses should consider seasonal plasticity in feeding patterns and refrain from premature conclusions based on short-term studies.