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Energetic consequenses of an inducible morphological defence in crucian carp

  • Lars Pettersson
  • Christer Brönmark
Publishing year: 1999
Language: English
Pages: 12-18
Publication/Series: Oecologia
Volume: 121
Issue: 1
Document type: Journal article
Publisher: Springer

Abstract english

Crucian carp (Carassius carassius) increases in

body depth in response to chemical cues from piscivores

and the deeper body constitutes a morphological defence

against gape-limited piscivores. In the ®eld, deep-bodied

individuals su€er a density-dependent cost when com-

peting with shallow-bodied conspeci®cs. Here, we use

hydrodynamic theory and swimming respirometry to

investigate the proposed mechanism underlying this ef-

fect, high drag caused by the deep-bodied morphology.

Our study con®rms that drag is higher for deep-bodied

crucian carp, both in terms of estimated theoretical drag

and power curve steepness. However, deep-bodied ®sh

swimming at the velocity associated with minimum cost

of transport, Umc, did not experience higher costs of

transport than shallow-bodied ®sh. Deep-bodied crucian

carp had signi®cantly lower standard metabolic rates,

i.e. metabolic rates at rest, and also lower Umc, and the

resulting costs of transport were similar for the two

morphs. Nevertheless, when deep-bodied individuals

deviate from Umc, e.g. when increasing foraging e€ort

under competition, their steeper power curves will cause

substantial energy costs relative to shallow-bodied con-

speci®cs. Furthermore, there is evidence that reductions

in standard metabolic rate incur costs in terms of lower

stress tolerance, reduced growth rate, and life history

changes. Thus, this work provides links between hy-

drodynamics, a cost-reducing mechanism, and a density-

dependent ®tness cost associated with an inducible



  • Ecology
  • Phenotypic plasticity á Carassius carassius á Respirometry á Cost of transport á Predation


  • ISSN: 1432-1939
Lars B. Pettersson
E-mail: lars [dot] pettersson [at] biol [dot] lu [dot] se



+46 46 222 38 18

+46 70 611 63 45



Centre for Animal Movement Research
Evolutionary Ecology, Department of Biology
Ecology building S-223 62 Lund Sweden