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Physiological plasticity v. inter-population variability: Understanding drivers of hypoxia tolerance in a tropical estuarine fish

journal contribution
posted on 28.10.2020, 00:00 by GM Collins, TD Clark, Alexander Carton
Physiological 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 6h 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. © CSIRO 2016.

Funding

Category 3 - Industry and Other Research Income

History

Volume

67

Issue

10

Start Page

1575

End Page

1582

Number of Pages

8

ISSN

1323-1650

Publisher

C S I R O Publishing

Peer Reviewed

Yes

Open Access

No

Acceptance Date

13/08/2015

External Author Affiliations

AIMS@JCU Collaborative Research Program, Townsville; James Cook University

Era Eligible

Yes

Journal

Marine and Freshwater Research

Usage metrics

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