Emmanuelle Chretien

McGill University
M.Sc. candidate

Supervisor: Lauren Chapman
Start: 2013-09-03
End: 2015-12-01
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Habitat selection and body size as potential drivers of intraspecific variation in thermal tolerance of Nile perch (Lates niloticus L.)
The general goal of my M.Sc. research is to evaluate the effects of body size and habitat conditions on thermal tolerance of Nile perch. In fishes, resting metabolic rate is known to increase with body size, and it is predicted that thermal sensitivity is also greater in larger individuals. Habitat specificity may also be an important predictor of thermal sensitivity, particularly when populations show habitat-related ecological divergence, as is the case with Nile perch. In Lake Nabugabo (Uganda), juvenile Nile perch captured near wetlands show larger gill size (and potentially higher hypoxia tolerance) than their conspecifics captured in well-oxygenated waters suggesting habitat-specific phenotypes. I conducted respirometry and critical thermal maximum (CTmax) trials on juvenile perches (5-20 cm TL) from these distinct habitats of Lake Nabugabo acclimated for a minimum of three days to ambient conditions (25.5 oC) and elevated water temperatures (27.5 oC, 29.5 oC, 31.5 oC).


hypoxia, environmental stress, ecophysiology