MEPS 373:187-191 (2008)  -  DOI: https://doi.org/10.3354/meps07855

COMMENT
N-specific metabolic data are not relevant to the ‘visual interactions’ hypothesis concerning the depth-related declines in metabolic rates: Comment on Ikeda et al. (2006)

James J. Childress1,*, Brad A. Seibel2, Erik V. Thuesen3

1Department of Ecology Evolution and Marine Biology, University of California, Santa Barbara, California 93106, USA
2Biological Sciences, University of Rhode Island, 100 Flagg Road, Kingston, Rhode Island 02881, USA
3Laboratory 1, Evergreen State College, Olympia, Washington 98505, USA

ABSTRACT: Ikeda et al. (2006; Mar Ecol Prog Ser 322:199–211) declared that they were testing the ‘visual interactions’ hypothesis for the decline in metabolic rates with depth in midwater animals, but their data and data analysis are irrelevant to this hypothesis for 4 reasons: (1) they do not show changes relative to the live mass of the animals studied; (2) they do not compare species-specific data; (3) they do not use evolutionarily significant descriptors of habitat depth; and (4) there are significant differences in the respirometry methods within their own data sets, and between those data and the data that support the ‘visual interactions’ hypothesis. Live weight mass-specific expression of rates is necessary when considering hypotheses concerning the evolution and function of living animals, although N-specific expressions may be useful in other contexts.


KEY WORDS: ‘Visual interactions’ hypothesis · Locomotor decline hypothesis · Midwater habitat · Mesopelagic · Bathypelagic · Crustacea · Metabolic rates


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Cite this article as: Childress JJ, Seibel BA, Thuesen EV (2008) N-specific metabolic data are not relevant to the ‘visual interactions’ hypothesis concerning the depth-related declines in metabolic rates: Comment on Ikeda et al. (2006). Mar Ecol Prog Ser 373:187-191. https://doi.org/10.3354/meps07855

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