Physiological responses of Perna. Sp. (Various size, 20 to 50mm) towards alternations in Marine Temperature

Abstract

The, Perna sp. is an important marine bivalve resource due to their dietary and medicinal properties. The increasing atmospheric CO2, ocean warming and consequent acidic changes of the ocean waters adversely affected these sedentary organisms by directly influencing the physiological activities and their energy levels. Experiments were conducted in the present study to infer the influence of temperature on the physiological responses of Perna sp. collected off Kadiapattanam coast, Tamil Nadu, India. The mussels were acclimatized at different temperatures viz., 25.0 to 40.0 °C and the oxygen consumption levels were examined. The results indicated that the smaller size group P. species. (viz., 20 mm shell length) was more active at 35.0 °C compared to the larger size groups. The oxygen consumption of P. indica acclimated at 35.0 °C was higher with 0.65±0.05 ml/lit/g/h than those 25.0 to 34.0 °C and 36 to 40.0 °C. It was also observed that at 25 to 30.0 °C, the mussels started secreting new byssal threads and the numbers of threads formed were at the rate of 6±0.03 of 20mm shell size and 4±0.05 threads formed of 30 and 40mm shell size mussels at 25.0 to 28.0 °C respectively per hour. However, byssal threads were not produced by those specimens reared at the elevated temperature of 35.0 °C. The observations point out to the fact that temperature increase due to global warming and size variation could adversely affect physiological responses of the Perna sp. in its natural marine conditions.