A first quantitative assessment of the ecology of cryptobenthic fishes in the Mediterranean Sea

Cryptobenthic fish communities are a rarely studied and ill-defined component of the marine benthos. Quantitative sampling of seventy-six 1 x 1 m plots at Cape ilo, Northern Adriatic Sea, yielded 522 cryptobenthic and 67 epibenthic individuals of 27 species. Canonical Correspondence Analysis (CCA) identified variation of 3 out of 17 habitat variables (depth, presence of bedrock, and presence of short thallus algae on boulders) as significantly and strongly correlated with species occurrence. Interpretation of CCA triplots allowed the description of niches of the 13 most abundant species, as well as the tentative identification of three major habitat types structuring the cryptobenthic fish community (inclined bedrock, infralittoral algae, and the deeper infralittoral mixed bottom). The study highlights the largely unstudied ecological relevance of the cryptobenthic fish community as revealed by an unexpected high diversity and the numerical dominance of some species which previously were considered rare. An improved definition of cryptobenthic fishes is provided.