Morphological and ecological investigations on sympatricLipophrys species (Blenniidae, Pisces)

Abstract

The three syntopic blenniidsLipophrys canevai, L. adriaticus, andL. dalmatinus were investigated off Katarina Island near Rovinj, Yugoslavia, in regard to their habitats and food organisms. The shallow, sheltered rocky sea shore turned out to be the characteristic habitat forL. dalmatinus andL. adriaticus, whereasL. canevai also inhabits surf-exposed biotopes. The overlap of the microhabitats was below 50 %. Algae are the main food of all three species with respect to biomass, but harpacticoids dominated inL. adriaticus and especiallyL. dalmatinus when considering abundance of food organisms. Overlap of trophic niches was high (80 %) betweenL. canevai andL. adriaticus but lower (<45 %) betweenL. dalmatinus and the other two species. Morphological studies considered external morphology, pigmentation, and anatomy of eyes, including the closely related, cave-dwellingL. nigriceps. This species reveals special adaptations to life in dimly lit biotopes: reduction of the basic melanophore pigmentation, development of clinging organs, and enlargement of eyes and lenses combined with an effective ratio of retinal elements and modes of accommodation. It is concluded that the four species are members of one “Lebensorttyp” (Riedl, 1966) of whichL. nigriceps has superimposed the basic characteristics with specializations to a greater and the other three species to a lesser degree.