Author(s): M. K. Vishnu Sagar; Sabu Joseph; P. S. Arunkumar; A. M. Sheela; Andrea Ghermandi
Linked Author(s):
Keywords: Shtamudi Lake; Ecosystem Services; Economy; Pollution; Euhaline
Abstract: Coastal lakes are under threat due to anthropogenic activities. The discharge of urban wastes mainly sewage, sullage and garbage into the coastal lake leads to the reduction of dissolved oxygen level in water and thereby causing threat to aquatic organisms especially to fish species. The rise in salinity due to climate change also imposes threat to fish species. Attempt has been made to study the effect of coastal hypoxia and rise in salinity on fishery resources in a Ramsar site, Ashtamudi lake (ASL) in Kerala, SW coast of India. ASL (Area=62 km), is a shore perpendicular brackish water lake with rich biodiversity. The ASL is divided into six zones (I-VI). Lake surface and bottom water samples were collected from 58 sites for non-monsoon (NMN) and monsoon (MN) seasons of 2017, and analyzed for various physcio-chemical parameters. The present study reveals that southern zone (Zone I) of lake is more polluted with organic matter and high concentration of nutrients especially NO -N (0.09-4.45 mg L and 0.12-6.32mg L) and NH -N (1.85-5.65 mg L and 0.64-9.21 mg L) for both surface and bottom waters during NMN, and develops an acute (DO=2-4 mg L) to chronic (< 2) hypoxic conditions especially for bottom waters. The salinity content of lake varies from 12.6 to 31.7 ppt. The major part of lake is presently in polyhaline condition (18-30 ppt), and estuarine zone (Zone-II) shows euhaline condition (> 30ppt), which leads to loss of clamp diversity in estuarine zone. The high costal hypoxic and anoxic conditions along with high salinity develop stress and damage to aquatic organism especially fishery diversity and loss on lake economic potential.
Year: 2018