Energetic consequenses of an inducible morphological defence in crucian carp
Author
Summary, in 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
defence.
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
defence.
Department/s
Publishing year
1999
Language
English
Pages
12-18
Publication/Series
Oecologia
Volume
121
Issue
1
Document type
Journal article
Publisher
Springer
Topic
- Ecology
Keywords
- Phenotypic plasticity á Carassiuscarassius á Respirometry á Cost of transport á Predation
Status
Published
Research group
- Biodiversity and Conservation Science
- Aquatic Ecology
ISBN/ISSN/Other
- ISSN: 1432-1939