Analysis of Plankton Intake to the Growth and Omega-3 Fatty Acid Content of Milkfish (Chanos chanos Forsskal, 1775)

The aim of the present study was to examine the food, growth, and omega 3 fatty acid content of milkfish (Chanos chanos) in Sidoarjo fish pond, East Java. The study was conducted by spreading 5,000 fish milkfish seeds (5-7 cm long and 0.6-1.0 g) to the fish pond. The length and weight of milkfish were measured, and the digestive tract was isolated. For sampling, a plankton net was used and samples were preserved in 1% Lugol solution. Data were analyzed to determine the food type and selection, growth rate, relative intestine length, and weight length relationship. The recorded relative intestine length of milkfish was 5.4-6.4 cm and was categorized as herbivorous fish. The food type was phytoplankton with a length of <14 cm and zooplankton with a length of >15 cm. The proportion of zooplankton in the fish intestine increased with its size. The phytoplanktons found dominantly in the digestive tract were Chaetoceros sp. and Nitzschia sp.and zooplankton were Calanus sp < em>. and Cyclop sp < em>. The daily length growth rate ranged from 0.008 to 0.283 cm, while the daily weight growth rate ranged from 0.5 to 1.16 g. The length-weight relationship of milkfish (Chanos chanos) can be determined by equation W=0.1466x with the regression index R2=1. Thus, milkfish (Chanos chanos) tended to have isometric growth patterns with the length and weight and were directly proportional to the omega-3 content in the milkfish body