Effect of the artisanal shrimp fishery on the ichthyofauna in the coastal lagoon of Santa Maria la Reforma, southeastern Gulf of California

The effect of the artisanal shrimp fishery on the fish fauna in the coastal lagoon of Santa Maria la Reforma, Mexico, was assessed. Twenty-nine stations were sampled monthly for shrimp and fin fish during six months, from December 2001 to May 2002, using small boats fitted with outboard engines and the three fishing gears employed by shrimp fishermen in the area: small shrimp trawl net, gillnet, and suripera net. Each sampling period lasted five days. In total, 11,368 individuals were caught, comprising 173 fish species. The species best represented in terms of number and biomass included the commercially important species Eucinostomus entomelas, Sphoeroides annulatus, Urotrygon chilensis, and Diapterus peruvianus. The highest abundance and biomass, as determined by boostrapping of the lognormal-based estimator, were caught with the shrimp trawl net. The mean total length of the fish captured was 17.4 cm for the gillnet, 15.8 cm for the shrimp trawl net, and 13.4 cm for the suripera net. The fishing gear that had a greater impact on the fish fauna were the shrimp trawl net and the gillnet, because they caught the greatest number of fish, biomass and diversity, and a large quantity of small individuals. These two fishing gears caught fish fauna from both the bottom and the water column, and showed the lowest fish/shrimp ratio in kilograms. The shrimp trawl net caught a 6:1 ratio, the gillnet a 15:1 ratio, and the suripera net a 1:1 ratio.