Fish assemblages of Cais do Carvão Bay (Madeira Island) determined by the visual census technique

Abstract

Fish assemblages in Cais do Carva˜o Bay, Madeira Island, a proposed marine protected area (MPA), were determined from a diver visual census. A total of 32 transect counts were performed. Habitats sampled included sandy bottom, rocky boulders, vertical walls and rocky outcrops. Species richness, diversity, density, trophic structure, size and spatial organization were documented for the fish assemblages. Forty-four species from 23 families were encountered; 32% belonged to Sparidae (10) and Labridae (four). The greatest species richness (25) was observed in rocky boulder habitat at 10-15 m depth, while the lowest (five) occurred over a deeper sand habitat. The greatest density (760Á5 individuals per 100 m 2 ) was recorded over rocky outcropping (20-25 m deep), and the lowest of 11Á6 individuals per 100 m 2 was over a sand bottom at 10-15 m depth. Thalassoma pavo, Abudefduf luridus and Chromis limbata had higher densities on hard bottoms, while Heteroconger longissimus was the most abundant species in sand bottom habitats. No significant differences were detected for all indices calculated among depth intervals for sand and rocky boulder stations. Sand and rock boulder substratum, however, differed significantly for the 10-15 m depth stratum. # 2005 The Fisheries Society of the British Isles

Assessing hotspots within hotspots to conserve biodiversity and support fisheries management

“…The community structure was comparable to other studies in the Macaronesian region that also used visual censuses, such as the Azores (Harmelin-Vivien et al 2001, Berton cini et al 2010), Madeira Island (Ribeiro et al 2005) and the Canary Islands (Falcón et al 1996). In general, sparids, la brids and carangids were the most diverse groups, and carnivores dominated the as sem blages, whereas herbivores and omnivores were only present at low percentages.…”

“…In general, sparids, la brids and carangids were the most diverse groups, and carnivores dominated the as sem blages, whereas herbivores and omnivores were only present at low percentages. Assemblages in this study have about half of the species in common with assemblages in Madeira (Ribeiro et al 2005) and about two-thirds with those in the Canaries (Falcón et al 1996). In general, the ichthyofaunas of these Macaronesian islands are more similar to each other than to that of the Portuguese mainland and the Mediterranean (Santos et al 1995, HarmelinVivien et al 2001, although some species overlap.…”

“…On the one hand, rocky areas are structurally more complex and offer a wider range of habitats and refuges than sediment, resulting in higher fish biodiversity (e.g. García-Charton et al 2004, Ribeiro et al 2005, Pittman et al 2007). On the other hand, distance to sediment does not merely distinguish between hard and soft bottom but also shows edge effects between both habitat types (Schmiing et al 2013), as shown by small peaks at about 10 m distance to sediment, i.e.…”

Movements of grey mullet Liza aurata and Chelon labrosus associated with coastal fish farms in the western Mediterranean Sea

“…The abundance and the approximate size distributions of grey mullet around farms in the Guardamar Bay were estimated by conducting rapid visual counts (RVCs; Kingsford & Battershill 1998) to reduce count bias (Ribeiro et al 2005), following the method out- Fig. 1.…”

The spread of an Atlantic fish species,Pomadasys incisus(Bowdich, 1825) (Osteichthyes: Haemulidae), within the Mediterranean Sea with new additional records from the French Mediterranean coast

“…This subtropical species naturally entered the Mediterranean Sea through the Straits of Gibraltar. Its main distribution encompasses the eastern part of the Atlantic Ocean, from Angola (Osorio 1909) to Gibraltar (Palacky 1895), including the Canary Islands (Vinciguerra 1883;Murray et al 1912;Bianchi 1984), Madeira (Günther 1859;Andrade & Albuquerque 1935;Ribeiro et al 2005) and the Cape Verde Islands (Osorio 1909). In fact, it was censused in Morocco (Bauchot 1963), Mauritania (Pellegrin 1914;Maigret & Ly 1986), the Ivory Coast and Senegal (Séret & Opic 1990) and the Gulf of Guinea (Fowler 1936;Blache et al 1970), where it would inhabit brackish waters of several islands (Osorio 1895).…”