Optimum Food Type, Feeding Schedule and Prey Density for the Zoea Larvae of the Crucifix Crab, Charybis feriatus (Crustacea:Decapoda:Portunidae)

Feeding experiments were carried out on the zoea larvae of the crucifix crab, Charybdis feriatus. The 1st experiment aimed to find out which among the rotifer Brachionus sp., brine shrimp Artemia sp. nauplii, and combination of both, would be a better diet to support survival, development of the zoeal larval stages (Z1-Z5) and metamorphosis to megalopa. In this experiment, the timing of introduction and cessation of rotifers, and co-feeding with brine shrimp nauplii was also determined. The 2nd experiment determined the density of Artemia nauplii that can support up to postmolt and the possibility of reducing prey density as zoeal stage progresses. Results showed high survival of Z1-Z2 larvae when fed purely with Brachionus but none of the larvae reached Z4 stage. When fed purely with Artemia nauplii, all the larvae died at Z3. Highest survival, fastest development and successful metamorphosis to megalopa was obtained on larvae fed with rotifers alone in Z1 and combination of rotifers and brine shrimp nauplii from Z2 onwards. Survival dropped when rotifers were removed from the diet in the later zoeal stages and when density of Artemia nauplii was gradually lowered from 2.0 nauplii ml^-1 at Z1 to 0.5 nauplii ml-1 at Z5. Larvae fed with Artemia at a constant density of 2.0 nauplii ml^-1 in all zoeal stages (Z1-Z5) resulted to highest number of megalopa produced. These results advance the development of hatchery techniques for the crucifix crab, C. feriatus.