Ichthyodiversity In Rice Agroecosystem In Seberang Perai Tengah, Pulau Pinang, Malaysia

Abstract

Fish dynamic studies in rice agroecosystem are still lacking in Peninsular Malaysia. This study aim to explore the community structure of fishes in rice agroecosystem in different stages, habitat and seasons of paddy planting. Multiple sampling gears were used, including cast net, gill net and scoop net. Twenty-six species of fishes were recorded from 14 families, dominated by Cyprinidae, followed by Osphronemidae, Bagridae and Clariidae. Fish communities based on rank abundance curves possess log normal distribution. Species diversity, species richness and species evenness in both seasons were similar but species richness between seasons did not have significant differences. Species diversity is the highest at reproductive (Shannon; 1.83 ± 0.17 and 1.93 ± 0.10) while, species evenness is the highest at vegetative (Evenness; 0.70 ± 0.10 and 0.69 ± 0.10) but species richness is the highest at the ripening stage (Margalef; 1.81 ± 0.57 and 2.98 ± 0.21). Species diversity and evenness were the highest in the river meanwhile species richness is higher in the concrete canals and earth ditches. The significant difference (p < 0.05) of species richness was observed between both seasons across all stages in all habitats except river during vegetative and reproductive stage. Fish taxonomic diversity at all stages and habitats did not have significant differences (p > 0.05). However, dendrogram and nMDS results showed that fish assemblages were separated into two groups (69% similarity) and three groups (80% similarity).