Hydrology of the horseshoe crab nesting grounds at Pahang Coast, Malaysia

Abstract

ABSTRACT Selected hydrological parameters at the nesting grounds of horseshoe crabs along the Pahangcoast were determined. A complete year data from March 2010 to February 2011 was collected usingadvanced multiparameter meter model Hanna HI 9828 probe. The surface water temperature variedfrom 29.06 0 C - 19.36 0 C at Balok and 29.1 C-15.08 C at Pekan station with mean annual temperatureof 24.08±2.91 0 C at Balok and 22.97±3.26 C at Pekan. Surface water salinity varied from 30.11ppt-2.09ppt at Balok and 33.45ppt – 3.38ppt at Pekan station with mean annual salinity of 17.9±10.63ppt atBalok and 20.5±10.04ppt at Pekan coastal waters. Seasonal fluctuation in the pH of the water variedfrom 8.65-6.61 at Balok station and 8.18-6.12 at Pekan station. Throughout the sampling period thecoastal waters of both the sampling sites were well mixed. The Dissolved oxygen (DO) in the watervaried from 7.75-4.21ml/L at Balok and 7.75ppt – 3.06ml/L at Pekan station with mean annual DO of6.24±0.95ml/L at Balok and 5.76±1.08ml/L at Pekan coastal waters. Physicochemical parametersshowed apparent seasonal fluctuation in the salinity of the surface water was observed in both thesampling stations (P < 0.05) while other parameters such as temperature, pH and dissolved oxygendid not vary significantly.