Feed ration for different sizes of wild and hatchery-bred milkfish (Chanos chanos Forsskal)

Abstract

Intensified production of fish involves stocking at high densities and the use of artificial feeds. These practices result in eutrophication and environmental degradation mainly because of feed wastage and fish excreta. To minimize waste, the maximum amount of feed consumed by fish must be known. Food consumption and utilization, however, may vary with the size and physical condition of the fish. Milkfish Chanos chanos Forsskal and some hatchery-produced fish, such as seabass Dicentrarchus labrax L. have been observed to have morphological defects that could affect normal food intake and utilization. Jaw abnormalities in hatchery-bred milkfish interfere with feeding and result in very slow growth. In the Philippines, milkfish fry for production in ponds and cages are caught from the wild or produced through artificial spawning. Studies have been conducted to estimate the feed ration for milkfish reared in brackish water ponds where natural food contributes significantly to the nutrition of the fish. In ponds and marine cages, where fish are largely dependent on artificial feeds, daily feed ration has to be estimated. This study determined the maximum feed ration for different sizes of wild and hatchery-bred milkfish based on assimilation of energy.