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Continuous measurement of oxygen tensions in the air-breathing organ of Pacific tarpon (Megalops cyprinoides) in relation to aquatic hypoxia and exercise

Seymour, R. S., Farrell, A. P., Christian, Keith A., Clark, T., Bennett, M., Wells, R. M. G. and Baldwin, J. (2007). Continuous measurement of oxygen tensions in the air-breathing organ of Pacific tarpon (Megalops cyprinoides) in relation to aquatic hypoxia and exercise. Journal of Comparative Physiology B: biochemical, systemic, and environmental physiology,177(5):579-587.

Document type: Journal Article
Citation counts: Scopus Citation Count Cited 11 times in Scopus Article | Citations

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IRMA ID 80801157xPUB28
Title Continuous measurement of oxygen tensions in the air-breathing organ of Pacific tarpon (Megalops cyprinoides) in relation to aquatic hypoxia and exercise
Author Seymour, R. S.
Farrell, A. P.
Christian, Keith A.
Clark, T.
Bennett, M.
Wells, R. M. G.
Baldwin, J.
Journal Name Journal of Comparative Physiology B: biochemical, systemic, and environmental physiology
Publication Date 2007
Volume Number 177
Issue Number 5
ISSN 1432-136X   (check CDU catalogue open catalogue search in new window)
Scopus ID 2-s2.0-34249908341
Start Page 579
End Page 587
Total Pages 9
Place of Publication Germany
Publisher Springer Publishing Company
Field of Research 0606 - Physiology
0608 - Zoology
1116 - Medical Physiology
HERDC Category C1 - Journal Article (DEST)
Abstract The Pacific tarpon is an elopomorph teleost fish with an air-breathing organ (ABO) derived from a physostomous gas bladder. Oxygen partial pressure (PO2) in the ABO was measured on juveniles (238 g) with fiberoptic sensors during exposure to selected aquatic PO2 and swimming speeds. At slow speed (0.65 BL s(-1)), progressive aquatic hypoxia triggered the first breath at a mean PO, of 8.3 kPa. Below this, opercular movements declined sharply and visibly ceased in most fish below 6 kPa. At aquatic PO, of 6.1 kPa and swimming slowly, mean air-breathing frequency was 0.73 min', ABO was PO2 10.9) kPa, breath volume was 23.8 ml kg(-1) rate of oxygen uptake from the ABO was 1. 19 mi kg(-1) min(-1), and oxygen uptake per breath was 2.32 ml kg(-1). At the fastest experimental speed (2.4 BL s(-1)) at 6.1 kPa, ABO oxygen uptake increased to about 1.90 ml kg-1 min(-1), through a variable combination of breathing frequency and oxygen uptake per breath. In normoxic water, tarpon rarely breathed air and apparently closed down ABO perfusion, indicated by a drop in ABO oxygen uptake rate to about 1% of that in hypoxic water. This occurred at a wide range of ABO PO2 (1.7-26.4 kPa), suggesting that oxygen level in the ABO was not regulated by intrinsic receptors.
Keywords fish
respiration
air-breathing
bimodal gas exchange
oxygen receptors
african lungfish
gas-exchange
resoponses
water
temperature
vertebrates
physiology
transport
DOI http://dx.doi.org/10.1007/s00360-007-0156-5   (check subscription with CDU E-Gateway service for CDU Staff and Students  check subscription with CDU E-Gateway in new window)
 
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