Resumo

ACEVEDO-CERVANTES, Alejandro; LOPEZ-MARTINEZ, Juana; HERRERA-VALDIVIA, Eloisa  e  RODRIGUEZ-ROMERO, Jesús. Abundance, dominance and diversity analysis of the demersal fish community analysis at 90 to 540 meters of depth in the Gulf of  California, Mexico. INCI [online]. 2009, vol.34, n.9, pp.660-665. ISSN 0378-1844.

An analysis of the demersal fish community of the eastern continental slope of the Gulf of California, México, was performed. Samples were obtained with a trawl net at 90-540m of depth by three separate research surveys. Temperature-salinity diagrams showed two main water masses, one represented by the Gulf of California water mass, down to a depth of 540m, and a deeper one corresponding to the sub-surface Pacific water mass. Depth profiles for temperature and dissolved O₂ were obtained, and plots constructed from them. These profiles showed that temperature and O₂ concentration decreased gradually along a smooth gradient to a minimun of 7°C and 0.1ml·l^-1, respectively, at 540m deep. Seventy-one species belonging to 35 families were found. Average maximum and minimum overall diversity (H´) values were 2.2 and 0.8 bits/ind and the specific richness (R) index value were 3.6 and 0.2. Caelorinchus scaphopsis, Merluccius productus, Pleuronichthys verticals, Sebastes spinorbis, Microlephidium verecundum, Lepophidium prorates. and Lophiodes spilurus were the most dominant species, based on the relative importance index. The fish community structure suggests two different communities with two groups of species, one at 90-270m deep that shows strong associations with moderate to high diversity values and specific richness, with shared dominance by numerous species, and a second community made out of typical deep water species, with low diversity and dominance featured by a few species. The data suggests that environmental conditions play an important role in the distribution and the community structure of these species.

Palavras-chave : Borde Continental; Demersal; Golfo de California; Peces de Aguas Profundas.