Aquaculture for the Conservation of Native Fish Species In Southeastern Mexico

Populations of native species of fish have been severely depleted in Southeastern Mexico, particularly in the State of Tabasco where the consumption of fish is culturally a tradition. Exploitation is intensive in those species with high values in the market; snooks, tropical gars and native cichlids are highly appreciated in the region, increasing the fishing pressure as human population rises. Tabasco is located in a very large floodplain and human activities –such as cattle ranching and agricultural practices- have turned vast areas of wetlands into ranches or farming land. This loss of environments for feeding, spawning, or hiding have also impacted fish populations. In Mexico, aquaculture has focused mainly in the production of introduced species, been tilapias, carps, rainbow trout, and shrimps the main species cultivated. In our region tilapia and shrimp culture are the center of attention. However, in our laboratory, since 1985, we initiated studies regarding the biology and ecology of native species aiming to generate enough information in order to propose aquacultural practices. To date, we have generated the complete technological package for tropical gar (Atractosteus tropicus) culture. Regarding the freshwater cichlids castarrica (Cichlasoma urophthalmus), tenguayaca (Petenia splendida), and paleta (Vieja synspilla), we have partly generated the culture cycle in captivty, but more research is needed for culture systems and diets. Our latest incursions are with three species of snooks, (Centropomus undecimalis, C. parallelus, and C. Poeyi). So far, we have successfully induced spawning, but feeding of the larvae is still a problem. Few experiments regarding growth have been implemented and more research is needed regarding this group of fishes. In our laboratory we produce a small amount of juveniles of tropical gar (200,000) and native cichlids (300,000) per year. Most of them are used for grow-out, but part of the production is used for re-stoking in areas where populations have been depleted. Genetic variability is taking into account by using broodstock from different areas of the region. With the native cichlids, we have compared reproductive performance and growth in captivity using lots from four different areas.

Our extension efforts have focused on technology transfer using workshops and direct training in the field, regarding larval production and growth of gars and cichlids. Many local farmers prefer the use of native species in their farms, but research is needed to significantly improve the culture of these fish in order to compete with tilapias.