TY - JOUR
T1 - Should I stay or should I go?
T2 - Physiological, metabolic and biochemical consequences of voluntary emersion upon aquatic hypoxia in the scaleless fish Galaxias maculatus
AU - Urbina, Mauricio A.
AU - Glover, Chris N.
N1 - Funding Information:
Acknowledgments The authors are grateful for the technical assistance of Gavin Robinson and Renny Bishop. We thank Malcolm Forster for advice and constructive criticism on this manuscript. We are grateful to Dr. Anne Todgham and an anonymous reviewer for their feedback. This work was supported by grants from the Royal Society of New Zealand (Marsden Grant UOC0711) and the Brian Mason Scientific and Technical Trust (2011/22) to CNG. MAU was supported by a Ph.D. scholarship from the Chilean Government, CONICYT. Funding bodies had no direct role in the study.
PY - 2012/12
Y1 - 2012/12
N2 - 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.
AB - 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.
KW - Anaerobic metabolism
KW - Emersion
KW - Hypoxia
KW - Ion homeostasis
KW - Metabolic depression
KW - Metabolism
UR - http://www.scopus.com/inward/record.url?scp=84870386211&partnerID=8YFLogxK
U2 - 10.1007/s00360-012-0678-3
DO - 10.1007/s00360-012-0678-3
M3 - Journal Article
C2 - 22645056
AN - SCOPUS:84870386211
SN - 0174-1578
VL - 182
SP - 1057
EP - 1067
JO - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
JF - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
IS - 8
ER -