Efecto de la estación y densidad de siembra en el crecimiento e índice de condición fisiológica del ostión de placer Crassostrea corteziensis cultivado en Guasave, Sinaloa

Abstract

The search for native species of bivalves, with a potential for aquaculture, constitutes a global challenge. One of the alternative culture species is the Cortez Oyster, Crassostrea corteziensis (Hertlein 1951), which presents a high potential for aquaculture endeavors within the Tropical Pacific of Mexico and Central America. Hence, it is of utmost importance to establish the adequate stocking density that will optimize the culture of the species, thus, permitting better management and control of the organism’s growth up to its commercial size. An experimental culture was conducted in the estuary, La Pitahaya, Guasave, Sinaloa; the sowing of spat took place in January 2010 from spat produced in a laboratory. Stocking densities of 14, 28 and 42 organisms per Nestier oyster boxes (NOB) were evaluated, taking into consideration growth in height, survival and physiological condition index of the organisms and its relationship to food availability and physicochemical factors of the water in which the culture took place. Within the culture site, sea temperatures showed a seasonal variation, with minimum values recorded during winter periods and maximum values occurring in the summer, (18.5 to 32.5 °C). Salinity varied between 25 and 39.5 mg L-1, while dissolved oxygen concentration was between 5.3 and 8.63 mg L-1. The total duration of the culture was thirteen months. The NOB that had a stock density of 14 organisms per NOB resulted in oysters of 77.38 ± 1.08 mm (mean and standard error, organisms with a stock density of 28 organisms per NOB in a size of 85.55 ± 1.29 mm and those with a stock density of 42 organisms per NOB obtained a size of 82.10 ± 1.41 mm. The growth of the organisms, cultivated at 14 per NOB were significantly lower (P<0.05) than those cultivated at stock densities of 28 and 42 organisms per NOB. These results suggest the possibility of obtaining good yields using stock densities of 28 and 42 organisms per NOB, while conducting proper maintenance of the culture system. In general, a very high survival percentage was obtained throughout the culture period, with no difference being attributed to the various densities. The lowest physiological condition index for the Cortez Oyster, Crassostrea corteziensis, was recorded during the summer when sea water obtained maximum temperatures of 31-32.5 °C. The microbiological quality in the estuary La Pitahaya was adequate throughout the culture cycle.