Coastal oceanographic processes associated with blood cockle (Anadara granosa) induce spawning season in Kapar, Selangor, Malaysia

Study on coastal processes in Kapar waters was conducted from 2008-2016. The aim of this study is to identify potential blood cockle (Anadara granosa) induce spawning ground based on physical intermittency. A total of 132 sampling stations were recorded. A thermal power station situated 2 km away is discharging treated warm water (<40 °C) on to the open sea causing the Sea Surface Temperature at near-by cockle culture to intermittent between 31-34 °C while the temperature at the bottom (at 6-8 m Mean Sea Level, MSL) is constant between 29.5 °C and 30.5 °C. The results suggested that Kapar waters have two seasons of low waters annually (January-March and June-September, respectively) and the Lowest Astronomical Tide (LAT) occur in late January-February while Great Diurnal Tide is observed on the same period. The bathymetry suggested the present of deep water (6-8 m, MSL) towards the end of cockle culture lot which is closed to merchant shipping lane near Port Klang. Based on water elevation, an area of 255.4 ha within cockle culture lots were identified to have this bottom temperature intermittency (29.5-34.0 °C) during its GT and it associated with cockle induce spawning condition. But this area was left out for cockle culture due to its typical depth (>3 m MSL) which prevents cockle farmers from harvesting due to their maximum of 3 m long hand dredge. Thus, this information could be useful for cockle sustainable management plan in near future.