Diversity of soft-bottom macroinvertebrates from the continental shelf off Jalisco and Colima, Mexico

Three cruises (DEM I, II and III) were conducted along the coast of Jalisco and Colima (Mexico) during three hydroclimatic seasons, defined by the pattern of the surface currents. Trawl samples were taken at seven sites along the coastline and four bathymetric levels (20, 40, 60 and 80 m). During the three cruises, 170 invertebrate species were identified. The crab Portunus xantusii affinis was the most abundant species: 62.6% during DEM I, 26.8% during DEM II and 42% during DEM III. The diversity (H′) estimated was moderate to low, of 1.93, 2.62 and 2.39 for the three cruises, respectively. No significant differences in diversity were observed among the three cruises and the differences in diversity among depths were only significant during DEM I. The minimum sample sizes for diversity and richness indicate that at least 20,422 organisms are needed to estimate diversity and 34,476 for richness.