Fish associated with fish aggregation devices off the Canary Islands (Central-East Atlantic)

Sixteen fish aggregation devices (FADs) were deployed in 50 to 500 m deep o f water in the Canary Islands. Species composition and abundance were deter mined by visual census carried out by divers on 55 occasions from April to October 1995 and from August 1996 to May 1997. A total of 15 species repres enting nine families of fish were observed. Pseudocaranx dentex (Bloch and Schneider, 1810), Seriola spp. and Naucrates ductor (Linnaeus, 1758) were t he most abundant species. The number of species associated with FADs increa sed with immersion time, but fish biomass did not increase. The maximum num ber of fish species registered exactly under the FADs at any one time was f ive. The average estimated biomass was 9.47 Kg per FAD (SD=25.2). However, when only baitfish were taken into account, the mean aggregated fish biomas s was 3.20 Kg (SD=4.32). The estimated biomass was higher when Coryphaena s pp. was present, increasing to 53.9 Kg per FAD (SD=53.6). A significantly l ower fish biomass and number of species was observed in FADs deployed in sh allower waters (50-100 m depth).