High postural costs and anaerobic metabolism during swimming support the hypothesis of a U-shaped metabolism-speed curve in fishes.

Autor:	Di Santo V; Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138; vdisanto@fas.harvard.edu., Kenaley CP; Department of Biology, Boston College, Chestnut Hill, MA 02467., Lauder GV; Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2017 Dec 05; Vol. 114 (49), pp. 13048-13053. Date of Electronic Publication: 2017 Nov 20.
DOI:	10.1073/pnas.1715141114
Abstrakt:	Swimming performance is considered a key trait determining the ability of fish to survive. Hydrodynamic theory predicts that the energetic costs required for fishes to swim should vary with speed according to a U-shaped curve, with an expected energetic minimum at intermediate cruising speeds and increasing expenditure at low and high speeds. However, to date no complete datasets have shown an energetic minimum for swimming fish at intermediate speeds rather than low speeds. To address this knowledge gap, we used a negatively buoyant fish, the clearnose skate Raja eglanteria , and took two approaches: a classic critical swimming speed protocol and a single-speed exercise and recovery procedure. We found an anaerobic component at each velocity tested. The two approaches showed U-shaped, though significantly different, speed-metabolic relationships. These results suggest that ( i ) postural costs, especially at low speeds, may result in J- or U-shaped metabolism-speed curves; ( ii ) anaerobic metabolism is involved at all swimming speeds in the clearnose skate; and ( iii ) critical swimming protocols might misrepresent the true costs of locomotion across speeds, at least in negatively buoyant fish. Competing Interests: The authors declare no conflict of interest.
Databáze:	MEDLINE
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