Spatio-Temporal Changes of the Copepod’s Population Concerning Physicochemical Characteristics at Nagapattinam Coast, Southeast India

Raju P, Divya M, Prathiviraj R, Santhanama P, Prasathd BB and Saranyaa M

Published on: 2025-01-10

Abstract

The current research investigated the influence of seasonal variations in the physicochemical characteristics of water on the distribution and abundance of copepods in the coastal waters of Nagapattinam, Southern India. Monthly sampling was conducted from February 2019 to January 2020 from the Bay of Bengal on the Nagapattinam coast. The temperatures of air and surface water (°C) varied from 25 to 33 °C and 24 to 29 °C, respectively. Salinity (%) levels varied between 18 to 34, while pH values were 7.9 and 8.24. Dissolved oxygen concentrations fluctuated from 5.4 to 8.24 mg/L. Additionally, the ranges of inorganic nutrients were: NO3, NO2, PO?, SiO4 and NH4 were: 11.11-21.82 µmol/L; 0.54-2.6 µmol/L; 5.65-13.1 µmol/L; 29.94-35.10 µmol/L and 0.60-1.53 µmol/L respectively. The recorded range of Chlorophyll ‘a’ was 0.18-0.59 mg L-1. Totally 38 species of copepods were recorded during the study period and the ranges copepod of density, diversity, richness and evenness were 1196-14763 ind./L, 1.45-2.98, 0.51- 0.98 and 0.82-0.98 respectively. The study revealed that the distribution and diversity of the copepod population are significantly influenced by rainfall pattern and physicochemical parameters on the Nagapattinam coast, southern India.