Impact of Variation in Environmental Parameters on Abundance of Paracalanidae (Calanoida: Copepoda) from the Tropical Coast of India, Bay of Bengal

Copepods belonging to the family Paracalanidae are dominant in the tropical regions of the oceans. In the present study, zooplankton samples were collected from January to December 2019 at three stations off Marina coast, Chennai, India. Five species of Paracalanidae were reported in the present study, whereas Acrocalanus gracilis was found to be a dominant species throughout the study with a mean abundance of 47.65 ± 8.73 × 103 ind./m3. Overall, the density of Paracalanidae was the highest in January and the lowest in June. Pearson’s correlation and regression analyses were conducted between the density of Paracalanidae and the observed physicochemical parameters of the aquatic environment to emphasize the relationship between them. A high negative correlation coefficient was observed between the Paracalanidae abundance and the water temperature (–0.76) and ammonia content (–0.73), whereas a high positive correlation was observed between the Paracalanidae abundance and the dissolved oxygen (0.75). The regression coefficient (R2) between the Paracalanidae abundance and the water temperature and ammonia content was 0.57 and 0.53, respectively, which indicated a strong negative relationship between the Paracalanidae abundance and the water temperature and ammonia content. However, this study also showed a strong relationship between the Paracalanidae abundance and the water salinity, pH, and nitrate content.