Food availability estimation of the blood cockle, Anadara granosa (Linnaeus, 1758), from the aquaculture grounds of the Selangor Coast, Malaysia

Blood cockles, Anadara granosa (Linnaeus, 1758), were collected from the aquaculture grounds (4 stations) of the Selangor coast, Malaysia, and the water quality (water temperature, salinity, dissolved oxygen, turbidity, and chlorophyll a) was measured from September 2011 to June 2013. At all stations, the water temperature fluctuated around 30℃. At station C, located at the mouth of the Selangor River, the salinity was occasionally lower than 20 PSU. However, the salinity of the other stations fluctuated around 30 PSU. In addition, at all stations, the content of dissolved oxygen generally fluctuated around 3 mg.L-1 or above, and the turbidity changed irregularly, sometimes exceeding 300 Forumajin Turbidity Units. The chlorophyll a content fluctuated mainly ranging 4-20 µg.L-1 at all stations, and values above 20 µg.L-1 were occasionally observed. The phytopigment content, a food availability indicator, in the digestive gland tissue of the blood cockles collected from all stations fluctuated ranging 30-770 µg.g-1. However, there was no proportional correlation between phytopigment content in the digestive gland and chlorophyll a content at all stations. Therefore, even in a high chlorophyll a content (over 20 µg.L-1) environment, the accumulated phytopigment in the digestive gland was around 290 µg.g-1. In general, these results indicated the cockles were eating a sufficient amount of foods (organic materials including phytoplankton) all year round during the study period. And, the food availability environment in the aquaculture grounds of the Selangor coast was estimated sufficient to grow the blood cockle.