Larval rearing of Asian seabass using rotifer, protozoa, and Euplotes encysticus

Seed production of marine finfish in Malaysia is still facing problem particularly live feed for starter diet. Currently, aqua culturists use S or SS type rotifers, which have sizes from 100 to 200μm. Early stage larvae of some marine finfish species select feeds less than 100 μm. Protozoa is a collective term of aquatic microorganism that has been identified to be suitable live feed, as their body sizes are less than 100μm. Thus, the objective of this experiment is to compare the survival rates of Asian seabass larvae using four types of live feeds. Four types of live feed; rotifer, protozoa, E. encysticus, and mixed (rotifer, protozoa, and E. encysticus) were used in this experiment. The larvae were fed from 2 to 10 day-after-hatching. Asian seabass larvae were given the same amount of live feed in each larval rearing tank; twice a day. The feeding densities were 20 individual / mL for rotifers, protozoa, E. encysticus, and mixed group. Number of seabass larvae in each group was counted every day and their survival rates were determined. Starting from 3 DAH until 10 DAH, mixed group showed the higher survival rates than other groups. The most recommended live feed was mixed group

High growth rate using new type demand feeding system with image processing program and fish behavior.

Demand feeding system serves feeds to fish, when fish switch on feeders. Although demand feeding system has advantages, it still has problems, e.g. hierarchy problem of fish school and system learning period problem for fish. New type of demand feeding system was develop to solve these problems using fish behaviour and image processing system. At first, behaviour experiment was conducted using the image processing software Roborealm to obtain the optimum parameter for computer program. Through the behaviour experiment, two typical behaviour patterns were detected. When fish was hungry, fish group came to the water surface (H: parameter >63%), and when fish was not hungry, fish came to bottom (L: <45%) of fish tank. These two parameters were obtained and were put into the computer program in the workstation. HD Wi-Fi camera continuously recorded the real time fish behaviour in fish tank, and when fish group came to above the “H”, then the command was sent from workstation to microcomputer to send the order to feeding device to feed on. The results of feeding experiment showed this system could provide pellets to fish day and night time equally following fish behaviour. This feeding system could provide the pellets to fish based on fish requirements. The growth rate was higher than other feeding system (timer feeder and demand feeder using an infrared light sensor)