title: Routine metabolic rate of southern bluefin tuna (Thunnus maccoyii).
abstract: Routine metabolic rate (RMR) was measured in fasting southern bluefin tuna, Thunnus maccoyii, the largest tuna species studied so far (body mass=19.6 kg (+/-1.9 SE)). Mean mass-specific RMR was 460 mg kg(-1) h(-1) (+/-34.9) at a mean water temperature of 19 degrees C. When evaluated southern bluefin tuna standard metabolic rate (SMR) is added to published values of other tuna species, there is a strong allometeric relationship with body mass (423 M(0.86), R(2)=0.97). This demonstrates that tuna interspecific SMR scale with respect to body mass similar to that of other active teleosts, but is approximately 4-fold higher. However, RMR (not SMR) is most appropriate in ram-ventilating species that are physiologically unable to achieve complete rest. Respiration was measured in a large (250,000 l) flexible polypropylene respirometer (mesocosm respirometer) that was deployed within a marine-farm sea cage for 29 days. Fasted fish were maintained within the respirometer up to 42 h while dissolved oxygen dropped by 0.056 (+/-0.004) mg l(-1) h(-1). Fish showed no obvious signs of stress. They swam at 1.1 (+/-0.1) fork lengths per second and several fed within the respirometer immediately after measurements.
authors.affiliation: School of Earth and Environmental Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia. quinn.fitzgibbon@adelaide.edu.au
authors.forename: Q P
authors.initials: QP
authors.lastname: Fitzgibbon
authors.forename: R V
authors.initials: RV
authors.lastname: Baudinette
authors.forename: R J
authors.initials: RJ
authors.lastname: Musgrove
authors.forename: R S
authors.initials: RS
authors.lastname: Seymour
mesh_terms: D000818:Animals; D001481:Basal Metabolism / Q000502:physiology*; D001835:Body Weight / Q000502:physiology; D010100:Oxygen / Q000378:metabolism; D012119:Respiration; D013550:Swimming / Q000502:physiology; D013696:Temperature; D014413:Tuna / Q000502:physiology*
chemical_list: D010100:Oxygen