The distribution and feeding ecology of small-size epibenthic fish in the coastal Mediterranean Sea  <B>The distribution and feeding ecology of small-size epibenthic fish in the coastal Mediterranean Sea</B><P><B>C. Dieter Zander</B><I><P> Zoological Institute and Zoological Museum, University, D-20146 Hamburg, Germany</I><B><P> Abstract</B><BR> Small-size fish by definition reach a maximum size of only 10 cm. Therefore, many of them have been overlooked and have had to be newly described in the recent past. In the Mediterranean this group of fish is represented especially by blennioids and gobiids. Light seems to be one of the most important factors causing vertical and horizontal distribution. The trophic dimension of the niche is influenced by inter- and intraspecific competition, food supply, and size, all of which are dependent on the seasons. Densities of small-size species may attain 53 individuals per m2 on sandy bottoms when juveniles are growing up; density values are far lower in rocky habitats. Consequently, ecological efficiencies (consumption/production) also differ in these two habitats. Because rocks also supply prey organisms for many larger fish, it was advantageous to calculate the consumption efficiency for every prey component. By omitting barnacles, ascidians, bryozoans and larger molluscs, values become comparable to those of the sandy bottoms which range between 5 and 15%. Specific behaviours may lead to overexploitation of single mobile organisms by small epibenthic fish which implies coexistence of dense heterospecific populations.<I><P> Keywords</I>: depth distribution, prey abundance, consumption efficiency, overexploitation, ecological significance, ecological niche.<P>