Julie Ross B. Amor Kathleen Joy B. Talcon (February, 2002)
Philippine Science High School Western Visayas Campus – Department of Science and Technology (DOST-PSHS WVC), Brgy. Bito-on, Jaro, Iloilo City 5000, Philippines
ABSTRACT
This study determined the effect of different loading densities and duration of transport on percent survival of three-week old native catfish, Clarias macrocephalus fry within two weeks after simulated transport. Three-week old native catfish fry were collected from the larval rearing tanks (LRT) at the Southeast Asian Fisheries Development Center (SEAFDEC) in Tigbauan, Iloilo.
The native catfish fry were randomly selected and packed at loading densities of 1 000, 2.000 and 3 000 individuals per 10 li in 5 x 8″ polyethylene bags containing 100 mi of aerated freshwater (1:2, water: oxygen ratio). Each density level had three replicates. The bags were sealed and placed in a tray secured on top of a laboratory orbit shaker set at 50 rpm for four hours to simulate transport. Another set of fry was subjected to six hours of simulated transport. Percent survival of fry within two weeks after simulated transport were analyzed using Analysis of Variance and Duncan’s Multiple Range Test at = 0.05 (SAS System).
Results showed that stocking density and duration of transport significantly affected the percent survival of the C. macrocephalus Ity during transport, and within the two- week culture period. Fourteen days after simulated transport, percent survival dropped (54-41%) in fry subjected to four hours of simulated transport in all stocking densities. It was significantly lower (26-10%) for those subjected to six hours of simulated iransport and was lowest in the group with stocking density of 3 000 fry/10 li water subjected to six hours of simulated transport.
Results indicate that loading density and duration of transport influence the viability of the C. macrocephalus fry. Optimum loading densities resulting in high survival rates can be 1.000 up to 2000 ind. 7 10 11. However, the duration of transport must not exceed four hours. Loading density during transport of C. macrocephalus fry must be less than 1000 ind./10 li if the duration of transport will be more than four hours.