Seasonal Variation in the Biochemical Constituents, Percentage Edibility and Condition Index of the Estuarine Clam, Soletellina diphos (Linnaeus, 1771) (Mollusca: Bivalvia: Veneroida: Psammobiidae)

A variety of biochemical analyses and condition indices have been employed by various authors all over the world to assess the chemical and health index of bivalves. In order to understand the effect of seasonal climate change on the nutritive value and physiological fitness of an estuarine population of the psammobiid Soletellina diphos on the West coast of India. The present study was under-taken in order to determine the seasonal fluctuations of the biochemical constituents in different parts of the body and the percentage edibility and condition index. This study has shown that seasonality is related to significant alterations in the biochemical constituents, percentage edibility and condition index (p<0.001) of this population of S. diphos. These changes could be due to the clam’s seasonal activities, particularly those related to its reproductive cycle. Higher values of the protein and lipid contents were recorded during the post-monsoon period, whereas maximum concentrations of glycogen were detected during the winter season. On the other hand, the lowest protein and glycogen contents were recorded during summer, while minimal lipid contents were observed during the winter season. The Percentage Edibility (PE) and Condition Index (CI) significantly fluctuated during the annual cycle, with maximum values occurring during the post-monsoon period (September-October 2008) and the lowest values during winter (November-December 2008). Therefore, it seems that the best nutritive season for S. diphos is in the post-monsoon period (September-October), when the highest values of its biochemical composition, percentage edibility and condition index occur. However, during the summer season (April-May), the lowest levels of the organic constituents, the percentage edibility and the condition index were recorded. Hence, that season is not ideal from the nutritive point of view. The study concludes that the physiological activity, the nutritive value and the meat quality of the clam S. diphos are seasonally related. Moreover, such baseline information is important from the viewpoint of aquaculture, as it demonstrates the seasonal impact on the nutritive status, reproductive output and physiological fitness of S. diphos.