Macrobenthic mollusc fauna inhabiting <i>Halopteris</i> spp. subtidal fronds in Sao Miguel Island, Azores

Abstract

SUMMARY: The molluscan community structure (species composition, abundance, density and diversity) associated with common brown algae Halopteris spp. at seven subtidal sites on São Miguel island (Azores) wase studied and checked for differences between sites. A total of 8,921 specimens (29 species of Gastropoda, 7 species of Bivalvia) were recorded. Bittium sp., the most common species, representing 85.6% of the total number of molluscs sampled, was present at each site and the number of taxa found at each station ranged from 3 to 17. Four species (Bittium sp., Setia subvaricosa, Tricolia pullus azorica and Rissoa guernei) accounted for 96.6% of all the specimens sampled. The density of the molluscs reached 18,000 specimens/100 g of algal dry weight (ADW). No significant differences in species diversity were found between sites. Further multispecies analysis between sites were conducted with both clustering and ordination techniques, and showed some separation between samples from south and north locations. The species responsible for this separation were the endemic Azorean Rissoids Rissoa guernei and Setia subvaricosa.

Mollusc fauna associated with the Cystoseira algal associations in the Gulf of Trieste (Northern Adriatic Sea)

“…Species belonging to the family Rissoidae are usually abundant and very frequently found, together with species of genera Bittium, Tricolia, Jujubinus, Gibbula and Calliostoma (Poulicek, 1985;Sánchez-Moyano et al, 2000). Similar results were also obtained for the Black Sea (Çulha et al, 2010;Gozler et al, 2010), where physico-chemical conditions limit the number of species, and in the Azores in the Atlantic Ocean (Costa & Ávila, 2001;Ávila, 2003), where certain endemic species are present. Overall, mollusc assemblages associated with algal associations show high species richness and diversity.…”

“…These communities also play a role of habitat former (Giaccone & Bruni, 1971) since they display a three-dimensional structure that provides habitat and shelter for a large number of algae and invertebrates (Mann, 1973;Antit et al, 2013). The importance of these associations for fish (Lipej et al, 2009;Orlando-Bonaca & Lipej, 2005;Fiorin et al, 2008;Orlando-Bonaca et al, 2008a;Vergés et al, 2009;Cheminée et al, 2013) and invertebrate communities (Milazzo et al, 2000;Costa & Ávila, 2001;Chemello & Milazzo, 2002;Gozler et al, 2010;Urra et al, 2013) has already been the subject of investigation in different areas of the Mediterranean Sea. Nevertheless, many questions regarding relationships between macroalgae and benthic invertebrates still remain unanswered.…”

Temporal variation of the algae-associated molluscan assemblage of artificial substrata in Bay of Tunis (Tunisia)

“…Within macroalgal communities, benthic herbivorous invertebrates and fishes are important for the structure and dynamics of shallow rocky sublittoral communities (Andrew & Jones 1990;Bégin et al, 2004;Bussell et al, 2007). Among the rich faunal communities inhabiting algal bottoms, molluscs are one of the best represented and dominant taxa (Poulicek, 1985;Milazzo et al, 2000;Costa & Ávila, 2001;Rueda & Salas, 2003), being considered an important food source for higher trophic levels (Pohle et al, 1991;Ruitton et al, 2000;Pasquaud et al, 2010).…”

Comparison of the community structure of the marine molluscs of the “Banco D. João de Castro” seamount (Azores, Portugal) with that of typical inshore habitats on the Azores archipelago

“…A pattern that appears from this and other studies (see Costa and Ávila 2001) is that the average numbers and densities of species are lower at hydrothermal vents than at similar sites without hydrothermal activity. At Kraternaya Bight (Kurile Islands), Tarasov et al (1985Tarasov et al ( , 1986Tarasov et al ( , 1990 and Tarasov and Zhirmunskaya (1989) found that volcanic activity signiWcantly changed the structure and speciWc composition of the communities.…”

“…Comparable to these Wndings, we found striking changes in the relative densities of mollusc species in the presence of hydrothermal vents. In the Azores, in undisturbed environments (CAP), the most common littoral mollusc is B. latreillii (Ávila 2000c, 2003Costa and Ávila 2001). This species, however, is not common at the shallow hydrothermal vents of RQT and DJC.…”