Influence of environmental variability of La Cruz Lagoon (Sonora) on growth and condition of the Pacific oyster Crassostrea gigas

It was studied the effect of temperature, salinity, oxygen, chlorophyll a and seston on the growth and condition of Crassostrea gigas oysters cultivated in La Cruz lagoon (Sonora, Mexico). Biometrics (height, length and weight) of oysters were carried out fortnightly (April-August) and monthly (September-December), and multimode inference was used to describe the growth. It was determined by PCR analysis that pathogens (OsHV-1, Marteilia refringens and Perkinsus marinus) were absent in spat and adult oysters. The temperature influenced the growth and condition when the maximum values were detected in summer. In this period the oysters stop their growth in shell but the available food, indicated by the chlorophyll and seston, allowed the formation of meat. This strategy seems an adaptation of the oysters to the variation of temperature and situates its optimal development between 20-30 degrees C. Under these conditions, the model that best described the growth was the Schnute case 1. These results show that in spite of extreme temperatures the oysters showed a good development during cultivation.