Vol.4 No.4 – 13 : Effect of Different Stocking Density of Catfish on Microalgal species composition and Diversity Indices under Varying Weather Conditions

By: Manthaka Weeraphong¹, Hishamuddin Omar¹*, Syaizwan Zahmir Zulkifli¹ and Mohammad Noor Amal Azmai¹

Department of Biology, Faculty of Science, Universiti Putra Malaysia, Serdang Selangor Malaysia

Abstract

The threat of climate change, rising human population and food security are some of the issues that need to be addressed urgently. Therefore the objective of this study is to document species composition of microalgae and its diversity in different stocking density of catfish in varying weather conditions to minimize water usage and maximize production. Clarias gariepinus with size 10±0.2 cm and 18.5±0.3 g were placed in polytank of 300L under sheltered transparent roofing. The experimental set up comprising of control tank with 25 fishes and covered to prevent microalgal growth, 10, 15, 20 and 25 fishes for treatment 1, 2, 3 and 4, respectively.  Microalgae were sampled every 2 days; different mean light intensity and temperature represent different weather conditions were recorded. The totals of 29 genera 77 species of microalgae within 5 divisions were identified. The most abundant taxa were Chlorophyta (90%). The common genus in all weather conditions were Chlorella, Desmodesmus, Scenedesmus and Selenastrum. Shannon diversity index (H’), Simpson index, evenness and species richness were diversity indices that ranged from 0.59-2.82, 0.21-0.97, to 0.52-1.04 and 2.01-5.36, respectively. The highest stocking density of catfish (25 catfish; T4) under dry weather conditions also produce highest diversity indices.

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