Food shortage and the effect on growth, condition factor and fitness of Trevally (Caranx ignobilis) under rearing condition

Abstract

Caranx ignobilis, is one of the iconic culture species in Ambon inner bay recently, unfortunately feeding remains problematic, yet is of profound importance. This study is aimed to examine the effect of feeding and unfed period cycles on growth trajectories and the well being during treatment. In totall, 259 fish ranging in size of 17.05cm-20.47cm SL and weight between 142.00 gr - 221.25 gr were subjected to receive three different feeding regimes. All fish were kept in 3x3x3m pollyethylene net cages receiving 1 day unfed and 1 day re-feeding (1F1RF), 2 days unfed and 2 days re-feeding (2F2RF), 3 days unfed and 3 days re-feeding (3F3RF) were compared to the fish feed daily as control group. Low value fish of shortfin scad, Decapterus macrosoma, were given twice per day at 0900hrs-1000hrs am and 1600hrs-1700hrs pm as much as 15% of total biomass. Standard length and weigth were recorded once per two weeks for 5 months. Analysis of mean length at harvest time showed no significant differences (Fα 0.05 : 1.6297 <Fcritical , 0,05 (1), 3,36 = 2,866. Weight gain however, exhibited significant differences (F, α 0.05 = 3,239 >Fcritical = 2,866). Tukey test among treatments and control revealed significant differences, q value range from 8,23-14,29>qcritical0,05, 36, 4 = 3,845. No significant difference, however among treatments; q = 3,2<q 0,05,36,4 = 3,845. The value of CC > 1 indicating growth compensation, while the RCF = 1.36 suggesting the same body condition with control group and remain in good fit.