Ichthyofauna catch composition in a small-scale fishery from Isabel Island (southeastern Gulf of California), Mexico

Isabel Island is a National Park located in the northwest Mexico with an unprotected marine area, where the small-scale fishing is allowed. The impact of this activity in the ecosystem and exploited biological resources has not been evaluated. From May 2013 to April 2014 the fishing grounds of Isabel Island were monthly monitored. The most widely used fishing gears were the gillnet (96.4%), hook-and-line (2.1%) and long-line (1.5%). A total 2,388 specimens were caught, corresponding to 19 families, 33 genera, and 46 species. The most frequent species caught were Lutjanus peru (%IRI = 55.34), L. guttatus (%IRI = 16.01), L. argentiventris (%IRI = 11.53), Cynoscion reticulatus (%IRI = 3.23) and Hoplopagrus guentherii (%IRI = 3.02), representing 89.13% of the total catch. The diversity was low (H' = 2.01), dominated by few species (J' = 0.52), mainly snappers (Lutjanidae).