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Life history dependent morphometric variation in stream-dwelling Atlantic salmon
1S.O. Conte Anadromous Fish Research Center, US Geological Survey/Leetown Science Center, P.O. Box 796, One Migratory Way, Turners Falls, MA 01376, USA. bletcher@forwild.umass.edu
Oecologia
|September 10, 2003
Summary
Atlantic salmon parr (Salmo salar L.) exhibit distinct morphometric variations linked to their life histories. These shape differences can predict life history outcomes even before they are fully expressed, aiding in early detection of developmental trajectories.
Area of Science:
- Ecology
- Evolutionary Biology
- Ichthyology
Background:
- Atlantic salmon (Salmo salar L.) parr exhibit diverse life histories influenced by maturity and smoltification timing.
- Understanding morphometric variation is key to identifying early life history indicators in fish populations.
Purpose of the Study:
- To analyze the time course of morphometric variation in Atlantic salmon parr related to different life histories.
- To determine if fish shape can predict life history trajectories before their full expression.
Main Methods:
- Landmark-based geometric morphometrics applied to digital images of tagged Atlantic salmon parr.
- Discriminant function analysis and MANOVA used to assess shape differences among life history groups.
- Analysis conducted across different ages (age-0+ to age-2+) and seasons.
Main Results:
- Fish could be successfully grouped by life history from age-1+ (March) with 84-97% accuracy.
- Life history prediction success averaged 67% from age-1+ summer to smolting.
- Significant shape differences among life histories were detected from age-1+ summer onwards, with size influencing shape, particularly in later stages.
Conclusions:
- Morphometric variation is a reliable indicator of early life history expression in Atlantic salmon parr.
- Geometric morphometrics can serve as a tool to predict life history trajectories and study temporal/spatial variations.
- These findings contribute to understanding the developmental plasticity and ecological strategies of salmonids.