Role of fertilization, supplementary feeding and aeration in water quality changes and fry growth in intensive outdoor nursing of fringed lipped carpLabeo fimbriatus(Bloch)

Abstract

A 30-day nursery trial was conducted to study the contribution of fertilizers, feed and aeration on the growth performance of fringed lipped carp, Labeo fimbriatus fry. Twelve large outdoor concrete tanks (10 m x 5 m x 1.2 m each) provided with 15 cm soil base were divided into three treatment groups. The three treatments received varied input combinations such as: only fertilizer (T-1); fertilizer + supplementary feed (T-2); and fertilizer + supplementary feed + aeration (T-3). Each tank was stocked at 1000 spawn m−3. After 30 days of rearing, the addition of supplementary feeding (T-2) recorded an 18% increase in the production of fry by number and 5.35-fold increase by biomass than T-1. However, additional aeration in T-3 resulted in 14.8, 31.4 and 44.0% increase in survival, fry yield (in number) and biomass than those in T-2, respectively, signifying potential advantage of aeration during intensive nursery rearing phase. Aeration also helped to maintain good water quality and sustain higher biomass. The absence of supplementary feeding (T-1) in such high-density nursery rearing led to starvation stress and caused poor fry performance in terms of growth and survival. The study further reinstated that added inputs in the form of supplementary feeding and aeration reduced such stress, ensured better environmental conditions and fry performance and also increased the profit margin during high-density nursery rearing.