17 research outputs found
Haemoglobin function in aquatic animals: molecular adaptations to environmental challenge
Endobiont infestation, shell strength and condition index in wild populations of New Zealand abalone, Haliotis iris
Haemocyanin function in the New Zealand abalones Haliotis iris and H. australis: relationships between oxygen-binding properties, muscle metabolism and habitat
Whole blood-oxygen binding properties of four cold-temperate marine fishes: blood affinity is independent of pH-dependent binding, routine swimming performance, and environmental hypoxia.
Oxygen binding of erythrocruorin and coelomic cell haemoglobin from the terebellid polychaete Neoamphitrite figulus
A difference in optomotor behaviour of two Antarctic nototheniid fishes is correlated with the presence of a choroid rete mirabile and Root effect
Continuous measurement of oxygen tensions in the air-breathing organ of Pacific tarpon (Megalops cyprinoides) in relation to aquatic hypoxia and exercise
The original publication can be found at www.springerlink.comThe Pacific tarpon is an elopomorph teleost fish with an air-breathing organ (ABO) derived from a physostomous gas bladder. Oxygen partial pressure (PO(2)) in the ABO was measured on juveniles (238 g) with fiber-optic sensors during exposure to selected aquatic PO(2) and swimming speeds. At slow speed (0.65 BL s(-1)), progressive aquatic hypoxia triggered the first breath at a mean PO(2) of 8.3 kPa. Below this, opercular movements declined sharply and visibly ceased in most fish below 6 kPa. At aquatic PO(2) of 6.1 kPa and swimming slowly, mean air-breathing frequency was 0.73 min(-1), ABO PO(2) was 10.9 kPa, breath volume was 23.8 ml kg(-1), rate of oxygen uptake from the ABO was 1.19 ml 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 PO(2) (1.7-26.4 kPa), suggesting that oxygen level in the ABO was not regulated by intrinsic receptors.Roger S. Seymour, Anthony P. Farrell, Keith Christian, Timothy D. Clark, Michael B. Bennett, Rufus M. G. Wells and John Baldwi