Diversity, distribution, and conservation status of Macrobrachium shrimp in freshwater ecosystems of Aceh, Indonesia.

Abstract

Background and aim: Freshwater shrimps of the genus Macrobrachium play key ecological and socioeconomic roles in tropical freshwater ecosystems. However, their diversity, habitat associations, and conservation status remain understudied in Aceh Province, Indonesia. This study aimed to (1) assess the diversity and morphometric variation of Macrobrachium species, (2) map their distribution across lotic and lentic habitats in Aceh, (3) Assess the impact of environment variable on species composition and richness and (4) evaluate their conservation status based on the International Union for Conservation of Nature (IUCN) criteria and local environmental threats.

Materials and methods: Field sampling was conducted from September 2022 to December 2023 across 24 sites spanning 13 districts. Specimens were collected using hand nets and traps, and identified using morphological and morphometric criteria. Environmental parameters (temperature, pH, velocity, and substrate) were recorded, and biodiversity indices were calculated. Species distribution and conservation status were analyzed using local distribution (LD) indices and IUCN Red List categories.

Results: A total of 1,303 Macrobrachium specimens representing 13 species were recorded. Macrobrachium lanchesteri was the most abundant and widely distributed species (LD = 50%), particularly in lentic habitats. Species such as Macrobrachium pilimanus and Macrobrachium lar showed narrow distributions. Lotic habitats supported higher species diversity (H' = 1.28) compared to lentic ones. Environmental variables significantly influenced species presence. While 10 species were categorized as least concern, three species (Macrobrachium australe, Macrobrachium esculentum, Macrobrachium mammillodactylus) were unlisted by the IUCN, indicating data deficiency. Evidence of invasive species presence and habitat degradation was observed in several sites.

Conclusion: Aceh hosts a diverse assemblage of Macrobrachium species, but they are vulnerable to anthropogenic disturbances and invasive species. The findings underscore the need for habitat conservation, sustainable fisheries management, and expanded monitoring-particularly for data-deficient species and those with narrow distributions. Molecular tools and long-term ecological monitoring are recommended for future research to better support regional conservation planning.