Polychaete assemblages in the San José Gulf (Chubut, Argentina), in relation to abiotic and biotic factors.

CATALINA TERESA PASTOR

Marine Ecology An Evolutionary Perspective

Lugar: Blackwell Synergy; Año: 2000 vol. 21 p. 175 - 190

1439-0485

             Abstract: The composition and distribution of the polychaete assemblages of the San José Gulf (Chubut, Argentina) were described in relation to environmental variables using indicator species (TWISPAN) and canonical correspondence analysis (CCA). The polychaetes were collected in a benthic cruise performed October 1984. Sediments were collected at  110 sampling sites using a 0.25 m2 van Veen bottom grab or by divers in  near-shore areas and sieved with 1 mm mesh. A total of 73 polychaete taxa were collected and identified.Both analyse, revealed the presence of four main assemblages distributed according to depth, bivalves and seaweed abundance gradients: Asyllis-Eunice and AHarmothoë-Eunice assemblages occurred at the same depths (0-185 m) and substrata (poorly sorted rock and coarse sand), but were separated by bivalves and seaweed abundance, corresponding to the highest abundances of bivalves and the minimum abundances of seaweeds to Syllis-Eunice association. Ninoe-Glycera and  AAglaophamus-Fabriciinae n. d. 6@  assemblages also occurred at similar depths (0-60) and substrata (very well sorted medium-fine sand),  but differed in their composition of bivalves and seaweed abundances, corresponding to the AAglaophamus-Fabriciinae n. d. 6" association the minimum values of bivalves abundances and the maximum values of seaweeds abundances.  Key words: Polychaetes, assemblages, distribution, Argentina, Patagonian coast, Península Valdés.