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Global warming may disproportionately affect larger adults in a predatory coral reef fish
journal contribution
posted on 2017-06-01, 00:00 authored by V Messmer, M S Pratchett, A S Hoey, A J Tobin, D J Coker, S J Cooke, Timothy ClarkTimothy ClarkGlobal warming is expected to reduce body sizes of ectothermic animals. Although the underlying mechanisms of size reductions remain poorly understood, effects appear stronger at latitudinal extremes (poles and tropics) and in aquatic rather than terrestrial systems. To shed light on this phenomenon, we examined the size dependence of critical thermal maxima (CTmax) and aerobic metabolism in a commercially important tropical reef fish, the leopard coral grouper (Plectropomus leopardus) following acclimation to current-day (28.5 °C) vs. projected end-of-century (33 °C) summer temperatures for the northern Great Barrier Reef (GBR). CTmax declined from 38.3 to 37.5 °C with increasing body mass in adult fish (0.45-2.82 kg), indicating that larger individuals are more thermally sensitive than smaller conspecifics. This may be explained by a restricted capacity for large fish to increase mass-specific maximum metabolic rate (MMR) at 33 °C compared with 28.5 °C. Indeed, temperature influenced the relationship between metabolism and body mass (0.02-2.38 kg), whereby the scaling exponent for MMR increased from 0.74 ± 0.02 at 28.5 °C to 0.79 ± 0.01 at 33 °C, and the corresponding exponents for standard metabolic rate (SMR) were 0.75 ± 0.04 and 0.80 ± 0.03. The increase in metabolic scaling exponents at higher temperatures suggests that energy budgets may be disproportionately impacted in larger fish and contribute to reduced maximum adult size. Such climate-induced reductions in body size would have important ramifications for fisheries productivity, but are also likely to have knock-on effects for trophodynamics and functioning of ecosystems.
History
Journal
Global change biologyVolume
23Issue
6Pagination
2230 - 2240Publisher
WileyLocation
Chichester, Eng.Publisher DOI
eISSN
1365-2486Language
engPublication classification
C Journal article; C1.1 Refereed article in a scholarly journalCopyright notice
2016, John Wiley & Sons LtdUsage metrics
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Categories
Keywords
Plectropomus leopardusGreat Barrier Reefbody sizeclimate changecritical thermal maximummetabolic ratethermal toleranceAcclimatizationAnimalsAnthozoaCoral ReefsFisheriesGlobal WarmingScience & TechnologyLife Sciences & BiomedicineBiodiversity ConservationEcologyEnvironmental SciencesBiodiversity & ConservationEnvironmental Sciences & EcologyTEMPERATURE-SIZE RULECLIMATE-CHANGEBODY-SIZEMETABOLIC-RATEHEAT TOLERANCEAEROBIC SCOPEATLANTIC CODOXYGENIMPACTS\nPlectropomus leopardus\n