Evaluation of Temperature, Salinity and Bathymetry in the Indus Delta Creek System

Abstract

The Indus River Delta is ranked the fifth largest in the world, and is located at the periphery of the Indus River determining 563 km of the entire coast of Sindh. This delta plays animportant role in enhancing the economic, environmental and ecological welfare of the people in this region. This delta constitutes seventeen main creeks. It forms a remarkably uniform landform with large extensive mud flats being intervened by narrow creeks, which are remains of old Indus tributaries.The ecosystem of Indus Delta is characterized by having rich nutrients which offer a nursery as well as an early feeding ground for many varieties of shrimps and fish as well. This study provides the baseline information about temperature, salinity, and bathymetry in different creeks of the Indus delta. Out of 17 creeks, 13 creeks were studied during the survey period. In the study area, the temperature ranged from 14.5 oC- 31.1 oC in a year. The temperature difference is nearly constant in mid-May toward mid-September (29.60 oC -31.10 oC), except in the Chani Creek area, where it remained as 28 oC- 29.4 oC.During mid-September to November (Post Monsoon), the temperature was slightly lower than monsoon (23.2 oC to 29.4 oC). There is little effect of seasonal shift at the western creeks, Issaro, Waddi Khuddi, Patiani, Mal, Dabbo, Richhal, Chann, Chani, and Hajamro as compared to eastern Creeks and Jhang River. During Monsoon, the highest salinity values (32.9 to 36.9 psu) have been recorded at Issaro and Waddi Khuddi Creeks. The sea temperature and salinity have greatly affected the otholith formation in fish species.