Evaluating the Ecologigical Integrity of a Tropical Lake Using Community Degradation Index

Abstract

This study evaluated the ecological integrity of Stratum VII (Yeji sector) of Lake Volta, Ghana, using fish-based indicators, specifically diversity indices and the Community Degradation Index (CDI). Fish samples were collected from four fishing communities, namely; Fante Akura, Brekente, Tonka, and Vutideke between January and December, 2024. A total of 41 species belonging to 13 families were recorded, with Chrysichthys walkeri (39.46%), Chrysichthys nigrodigitatus (13.76%), and Schilbe mystus (13.12%) as the most dominant species, reflecting the resilience of opportunistic taxa. Diversity analysis showed healthy ecological environment at Stratum VII, with Shannon–Wiener index values ranging from 1.98 (Fante Akura) to 3.27 (Vutideke). The CDI values ranged from 1.10 (Vutideke) to 5.29 (Fante Akura), suggesting that despite existing anthropogenic stress, Stratum VII has not yet reached critical degradation level. Generally, CDI provided a more robust assessment by accounting for trophic interactions and species resilience, offering deeper insights into ecosystem degradation. Therefore, this study emphasizes the importance of integrating functional indices with conventional diversity measures in monitoring frameworks to inform sustainable management of Lake Volta and similar inland freshwater ecosystems in Ghana.