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Table 6 Morphological and behavioural observations of adult 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, 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

Erratic swimming, accelerated operculum, gasping, barbells vibration and frequent coming to the surface, feeding impaired

No behavioural abnormalities observed.

Normal movement and behavioural responses observed