Inter-Research
Marine Ecology Progress Series

ABSTRACT: While temperature records are available from otolith d¹⁸O profiles in fish, interpreting changes in otolith d¹³C remains ambiguous. We compiled a global database of published otolith d¹³C values for 60 species representing 30 families of marine fishes. Species' mean otolith d¹³C ranged from +0.5 to -8.6 ‰. Among-family variance in otoli d¹³C was uniquely explained by a morphometric index for aerobic swimming activity (caudal aspect ratio, r² = 0.61). The models that consistently explained the maximum among-species variance in otolith d¹³C included caudal aspect ratio and maximum depth of occurrence. Our analysis supports the use of otolith carbon-isotope ratios to indicate metabolism (primarily active) in marine fish. This information may be applied to studies of fish feeding and related food-web structure, both past and present.

KEY WORDS: Otolith · Stable isotopes · d¹³C · Marine fish · Metabolism · Swimming activity · Caudal aspect ratio · Morphometrics

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Published in MEPS Vol. 258 (2003) on August 29
Print ISSN: 0171-8630; Online ISSN: 1616-1599. Copyright © Inter-Research, Oldendorf/Luhe, 2003