FISH ASSEMBLAGES AS INDICATORS OF PEAT SWAMP HEALTH: EVALUATING FISH DIVERSITY IN THE SUNGAI KARANG FOREST RESERVE, SELANGOR, MALAYSIA

Abstract

Peat swamp forests are among the most distinctive and threatened freshwater ecosystems in Southeast Asia, providing critical habitats for endemic and endangered aquatic species. This study evaluated fish assemblages as indicators of peat swamp health in the Sungai Karang Forest Reserve, Selangor, Malaysia. Sampling was conducted over a month, from August 23, 2020, to September 24, 2020, across five habitat-diverse sites, utilizing two complementary capture methods, such as fish traps and scoop nets, to maximize species detection. A total of 423 individual fish representing 13 species, six families, and five orders were recorded. The Osphronemidae family was the most diverse, comprising over half of the total assemblage, with notable presence of Betta livida and Betta hipposideros, both classified as endangered by the IUCN. Catch per unit effort (CPUE) assessments revealed that Betta livida was the most captured species using fish traps and scoop nets combined, indicating its abundance. Pristolepis fasciata and Betta bellica also showed high capture rates, along with notable catches of Helostoma temminckii, Trichopodus trichopterus. Biodiversity was assessed using three ecological indices. The Shannon-Wiener diversity index yielded a value of 2.36, indicating moderate to high species diversity, while the Berger-Parker dominance index of 0.14 reflected low dominance by any single species. Notably, scoop nets proved more effective than fish traps in terms of capture volume and species range, accounting for 75.7% of the total individuals collected. Significant differences in catch composition between the two gear types were statistically supported (F = 56.573, p < 0.05), highlighting the influence of sampling methods on biodiversity assessments. The Sungai Karang Forest Reserve has a diverse freshwater fish community, highlighting its ecological importance. The presence of endangered species emphasizes the need to protect peat swamp habitats from threats like habitat alteration, runoff, and ecotourism. Ongoing biodiversity monitoring, habitat conservation, and community efforts are crucial to preserve Malaysia’s peat swamp ecosystems.