Study on bottom temperature condition associated with blood cockle Anadara granosa induce spawning affected by thermal plume discharge from nearby thermal power station in Kapar, Selangor

Three Acoustic Doppler Current Profiler (ADCP) samplings were conducted at Station KKKL6a (N3.13667, E101.29983) with approximately 1.2Km away from nearby Thermal Power Station (TPS) in Kapar, Selangor. Each sampling covers among three daily major tidal changes known as the Great Diurnal Tide (GT). The sampling were conducted on 6^th -10^th May 2016, 19^th - 26^th July 2016 and (&) 17^th - 24^th August 2016 respectively. Meanwhile a total of 132 sampling stations for temperature (temp) profile i.e., Sea Surface Temp (SST), 1.0m & 3.5m were conducted covering Kapar waters to Sungai Buloh waters.  All the data were combined & process for temp profile fromsurface to the bottom. The aim of this study is to investigate the bottom temp (bt) profile for every water elevation affected by the thermal plume discharge from the nearby TPS. The results (Table 1) suggested that bt trending during 8m water elevation with minimum  temp (min) of 29.82°C, maximum temp (max) of 31.31°C & temp difference (t-diff) of 1.49°C respectively. On 7m depth, the min is 29.90°C, max is 31.52°C, & t-diff is 1.62°C correspondingly. While at 6.0m the temp trend is 29.97°C, 31.35°C & 1.38°C respectively. On 5m depth, the result suggest min of 29.89°C, max of 31.41°C & t-diff of 1.52°C. While during 4m depth suggesting min of 29.91°C, max of 31.52°C & t-diff of 1.61°C. The bt start to intermittent (imt) at 3.5m depth proposing min of 29.01°C, max of 31.33°C & t-diff of 2.32°C individually. During 3.0m suggesting min, max and t-diff of 29.15°C, 31.56°C & 1.41°C accordingly. When the tide drop to 1.0m, the bt proposed min, max & t-diff as 29.01°C, 31.84°C & 2.83°C separately. While during the lowest tide (<0.5m), the SST interact with the bt suggesting the high bt sporadic with min, max & t-diff as 28.38°C, 33.64°C and 5.26°C respectively. This physical condition is associated with cockle induce spawning where the bt at KKKL6a is typically at 5-7m depth & t-diff is around 1.52°C - 1.62°C during typical water tides but GT, where it can lowered to 1.5m & some parts of the surrounding areas is exposed. While shallow waters where temp imt is about 2.32°C - 5.26°C. Thus this bt sporadic may rise from 1.52°C to 5.26°C with two interval tide between the lowest tidal during stipulated GT.

Keywords: Cockle induce spawning, bottom temperature intermittent, the great diurnal tide (GT), thermal plume, thermal power station, Kapar Energy Venture