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Table 5 Morphological and behavioural observations of juvenile of O. niloticus in low pH and control

From: Tolerance level of different life stages of Nile tilapia Oreochromis niloticus (Linnaeus, 1758) to low pH and acidified waters

Observations pH 3 pH 4 pH 5 pH 6 Control
Morphological None as mortality was recorded Very dark body colouration, slimy mucous secretions on the gills and body surface; peeling and skin erosion, bleeding from the dorsal fins and bending of the caudal fin, some fins became disintegrated Very dark body colouration, slimy mucous secretions on the gills and body surface; peeling and skin erosion, bleeding from the dorsal fins and bending of the caudal fin, some fins became disintegrated Normal body colouration except some few dark patches, no morphological abnormalities recorded. Normal body colouration, no morphological abnormalities seen
Behavioural None as mortality was recorded Erratic swimming, accelerated operculum, gasping, barbells vibration and frequent coming to the surface, feeding impaired
Swimming velocity decreased
Erratic swimming, accelerated operculum, gasping, barbells vibration and frequent coming to the surface, feeding impaired, Swimming velocity decreased No behavioural abnormalities observed. Normal movement and behavioural responses observed