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Physiological plasticity v. inter-population variability: understanding drivers of hypoxia tolerance in a tropical estuarine fish
journal contribution
posted on 2023-05-18, 21:11 authored by Collins, GM, Clark, TD, Carton, AGPhysiological plasticity and inter-population variability (e.g. local adaptation) are two key drivers in determining the capacity for species to cope with environmental change, yet the relative contribution of each parameter has received little attention. Here, we investigate the acclimation potential of two geographically distinct populations of the barramundi (Lates calcarifer) to diel hypoxia. Fish were exposed to a daily hypoxia challenge of 6 h below 62% saturation, down to a minimum of 10 ± 5% saturation, followed by a return to normoxia. Respiratory and haematological variables were assessed after 8 and 16 days of daily hypoxia exposure. Hypoxia tolerance (measured as the critical oxygen tension; [O2]crit) was not different between populations and not different from control fish after 8 days ([O2]crit = 20.7 ± 2.8% saturation), but improved similarly in both populations after 16 days ([O2]crit = 16.5 ± 3.1% saturation). This improvement corresponded with increases in haematocrit and haemoglobin, but not an increase in the mean cell haemoglobin concentration. Given the similarity of the response between these two geographically distinct populations, we conclude that hypoxia tolerance for barramundi may be more dependent on physiological plasticity than inherent variability between populations.
History
Publication title
Marine and Freshwater ResearchVolume
67Pagination
1575-1582ISSN
1323-1650Department/School
Institute for Marine and Antarctic StudiesPublisher
CSIRO PublishingPlace of publication
150 Oxford St, Po Box 1139, Collingwood, Australia, Victoria, 3066Rights statement
Copyright CSIRO 2016Repository Status
- Restricted