The Use of Water Exchange for Feeding Rate and Growth Promotion of Shortfin Eel Anguilla bicolor bicolor In Recirculating Water System

Abstract

The shortage of eel’s seed Anguilla spp. and it’s consumption size will induce the hunting of this species. Thus, stocks are critically endangered. Central Java have two indigenious species i.e. A. marmorata and A. bicolor bicolor. These two species will be endanger if management of stock do not conduct properly. The use of water exchange by replacing water volume for feeding rate and growth promotion of Indonesian shortfin eel A. bicolor bicolor in RWS will at least give a basic information in appropriate aquaculture systems and as a part of disaster mitigation of indegenious species extinction. The study used 3 replications and 3 treatments of water exchange, i.e. T1: 50, T2: 100, and T3: 200 % of water removed d -1. The fish were fed with approx. 2.2% dry basis of formulated feed. Tanks with volume of 1 m3 contain a density of approx. 20 kg seed stock of shortfin eel fingerlink size per m3 water in RSW. The result shows that feeding rate among treatments are significantly different (α < 0.001), where T1= 1.62±0.23% d-1, T2 = 1.89±0.06% d-1 and T3. Individual and Biomass weight gain increase (IWG: T1= 0.039±0.003, T2.= 1.99±0.06% d = 0.050±0.001, T3=0.076±0.002 kg and BWG: T1=7.087±0.443, T2 = 11.051±0.894, T3= 19.722±0.831 kg respectively) by increasing water exchange (α < 0.001). Meanwhile the absolute growth was found higher in individual (IAG) compare to biomass (BAG) and both of them increase by increasing water exchange (α < 0.001). Where for IAG: T1 = 55.42±3.69, T2= 71.02±2.40, T3=106.12±1.98% and BAG: T 1= 35.11±1.13, T2= 52.94±6.17, T3= 90.77±3.14% respectively