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dc.contributor.authorH. Routley, Matthewen_US
dc.contributor.authorE. Nilsson, Goranen_US
dc.contributor.authorRenshaw, Gillianen_US
dc.contributor.editorThomas P. Mommsen, Patrick J. Walshen_US
dc.date.accessioned2017-05-03T12:01:38Z
dc.date.available2017-05-03T12:01:38Z
dc.date.issued2002en_US
dc.date.modified2007-03-14T21:45:28Z
dc.identifier.issn10956433en_US
dc.identifier.urihttp://hdl.handle.net/10072/6803
dc.description.abstractThe majority of vertebrates are not tolerant to hypoxia but epaulette sharks (Hemiscyllium ocellatum) living on shallow reef platforms appear to tolerate hypoxic periods during tidal fluctuations. The effects of progressive hypoxia on the metabolic and ventilatory responses of these elasmobranchs were examined in a closed respirometer. In order to determine whether repeated exposure to hypoxia primes these sharks to alter their metabolism, one group of sharks was exposed to repeated sub-lethal hypoxia, at 5% of air saturation, prior to respirometry. In response to falling oxygen concentration [O2] , the epaulette shark increased its ventilatory rate and maintained its O2 consumption rate (VO2) down to 2.2 mg O/l at 25 degrees C. This is the lowest critical O2 ever measured for any elasmobranch. After reaching the O2crit of 2 22, the shark remained in the respirometer for a further 4.5 h of progressive hypoxia. Only after the O2crit fell to 1.0 mg/l was there a decrease in the ventilatory rate followed by a rise in blood lactate levels, indicating that the epaulette shark responds to severe hypoxia by entering a phase of metabolic and ventilatory depression. Interestingly, hypoxia tolerance was dynamic because hypoxic pre-conditioning lowered the VO2 of the epaulette shark by 29%, which resulted in a significantly reduced O2crit (1.7 mg O/l), revealing that hypoxic pre-conditioning elicits an enhanced physiological response to hypoxia. 2002 Elsevier Science Inc. All rights reserved. Keywords: Hypoxia tolerance; Ventilatory depression; Metabolic depression; Hypoxic pre-conditioning; Respirometry; Elasmobranch; Adaptive physiologyen_US
dc.description.peerreviewedYesen_US
dc.description.publicationstatusYesen_AU
dc.languageEnglishen_US
dc.language.isoen_AU
dc.publisherElsevieren_US
dc.publisher.placeNew Yorken_US
dc.publisher.urihttp://www.elsevier.com/wps/find/journaldescription.cws_home/525464/description#descriptionen_AU
dc.relation.ispartofpagefrom313en_US
dc.relation.ispartofpageto321en_US
dc.relation.ispartofjournalComparative Biochemistry and Physiology Part Aen_US
dc.relation.ispartofvolume131en_US
dc.subject.fieldofresearchHISTORY AND ARCHAEOLOGYen_US
dc.subject.fieldofresearchcode210000en_US
dc.subject.fieldofresearchcode270604en_US
dc.titleExposure to hypoxia primes the respiratory and metabolic responses of the epaulette shark to progressive hypoxiaen_US
dc.typeJournal articleen_US
dc.type.descriptionC1 - Peer Reviewed (HERDC)en_US
dc.type.codeC - Journal Articlesen_US
gro.rights.copyrightCopyright 2002 Elsevier : Reproduced in accordance with the copyright policy of the publisher : This journal is available online - use hypertext links.en_AU
gro.date.issued2002
gro.hasfulltextNo Full Text


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