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Updated: Apr 10, 2026

Modeling the Size Spectrum for Macroinvertebrates and Fishes in Stream Ecosystems
Published on: July 30, 2019
Shrinking fish: comparisons of prehistoric and contemporary salmonids indicate decreasing size at age across
Pablo Turrero1, Eva García-Vázquez2, Carlos Garcia de Leaniz3
1Department of Geology , University of Oviedo , C/ Jess Arias de Velasco, s/n. 33005, Oviedo, Asturias, Spain.
Abstract:
A comparison of Upper Palaeolithic and contemporary salmonid vertebrae from the Iberian Peninsula indicates that there has been a significant decrease in the mean body size for a given age among Atlantic salmon and brown trout inhabiting the southernmost range of their endemic distribution. Mean size at age was greater in prehistoric specimens for all age classes during the freshwater phase of their life histories. Fisheries-induced evolution (selection for smaller sizes) is an obvious explanation for the observed reduction in fish body size, but recent changes in the aquatic habitat affecting density-dependent growth cannot be ruled out.
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