Abstract

Hypoxia represents a significant challenge to most fish, forcing the development of behavioural, physiological and biochemical adaptations to survive. It has been previously shown that inanga (Galaxias maculatus) display a complex behavioural repertoire to escape aquatic hypoxia, finishing with the fish voluntarily emerging from the water and aerially respiring. In the present study we evaluated the physiological, metabolic and biochemical consequences of both aquatic hypoxia and emersion in inanga. Inanga successfully tolerated up to 6 h of aquatic hypoxia or emersion. Initially, this involved enhancing blood oxygen-carrying capacity, followed by the induction of anaerobic metabolism. Only minor changes were noted between emersed fish and those maintained in aquatic hypoxia, with the latter group displaying a higher mean cell haemoglobin content and a reduced haematocrit after 6 h. Calculations suggest that inanga exposed to both aquatic hypoxia and air reduced oxygen uptake and also increased anaerobic contribution to meet energy demands, but the extent of these changes was small compared with hypoxia-tolerant fish species. Overall, these findings add to previous studies suggesting that inanga are relatively poorly adapted to survive aquatic hypoxia.

Links

Publisher Full Text

Authors

Urbina MA, Glover CN

Institution

School of Biological Sciences, University of Canterbury, Christchurch, New Zealand. mauriciourbin@gmail.com

Source

Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology 182:8 2012 Dec pg 1057-67

MeSH

Adaptation, Physiological
Animals
Animals, Wild
Anoxia
Behavior, Animal
Diving
Energy Metabolism
Fish Proteins
Fresh Water
Glycogenolysis
Glycolysis
Hemoglobins
Mouth Breathing
Muscle, Skeletal
New Zealand
Osmeriformes
Random Allocation
Rivers
Sucking Behavior
Swimming

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22645056