ABSTRACT
Pen shell species such as Pinna bicolor and Pinna deltodes are found in the muddy region associated with intertidal seagrass in the coastal area of Pudupattinam. The pen shell is one of the sources of animal protein-rich, thereby encouraging the community of pen shells and their study worldwide. The water samples were collected for a year between January to December 2016 and analysed. Salinity (30.1-31.5), pH (8.1-8.2), EC value (39.79 103-46.09103 mho), turbidity 25-54 NTU, TSS value (5.51-108 mg/l), DO (4.45-5.74 ml/l), BOD (0.175 -1.05 mg/l), chemical oxygen demand (9.6-39.1 mg/l), chloride 14,276.8-16,124.9 mg/l), sulphate (1975.3-25 mg/l), ammonia (0.022-0.112 µm/l), inorganic phosphate (0.754 µm/l and maximum 1.568 µm/l), total nitrogen (10.829-29.509 µm/l), total phosphate (1.76-3.174 µm/l) and silicate (42.264-64.121 µm/l). Minimum and maximum water temperature ranges (26.9-30.6 °C) were recorded. A total of 623 Pinna bicolor and 1341 Pinna deltodes were collected during the same time and consisted of 305 males and 318 females and 558 males and 783 females, respectively. The improvements in the parameters of physico-chemical and statistical analysis have been shown to have a minor effect on the distribution of these two species in the present research, as environmental factors were not sufficient to influence their distribution.
