Growth rates in two natural populations of Gasterosteus aculeatus in northwestern Spain: relationships with other life history parameters

E San Miguel,C Fernández,J Castro,M Hermida,R Amaro

doi:10.32800/abc.2020.43.0233

E San Miguel, C Fernández + Show 3 more

Open Access

https://doi.org/10.32800/abc.2020.43.0233

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Abstract

We analysed growth rates of two natural populations of the three–spined stickleback fish, Gasterosteus aculeatus, in Galicia (north–west of Spain) where it has a strictly annual life cycle. We used the von Bertalanffy growth model to estimate nonlinear function for length–at–age data sets. These European peripheral populations reach the highest growth rates (k of the von Bertalanffy model > 0.4 month–1) known for this species. Instantaneous mortality rates and fecundity were computed using von Bertalanffy model parameters for each population. Mortality rates found in Galician populations were 2.0–2.3 higher times than those observed in general for Gasterosteidae. Combining both mortality and fertility, different intermediate fitness optima in each population were obtained for mature females. Overall, these differences in life history compared to other studied populations of sticklebacks can be interpreted as local adaptations to a Mediterranean climate type with high degree–days. Consequently, these populations at the edges of the species’ range may have adapted to the unique environmental conditions and may be of interest in ecology and conservation.

Highlights

The Mediterranean region is a biodiversity hotspot for freshwater ecosystems, harbouring many species and genetically distinct lineages that are of conservation concern (Araguas et al, 2012; Sharda et al, 2018)
By averaging r2 values, we obtained 91 %, which indicates good performance of the model, i.e. von Bertalanffy growth function (VBGF) accounted for 91 % of the variance in total length exhibited by these populations
The reproductive lifespan in a semelparous species is restricted to a single breeding season, even if age at maturity does not occur until after several years of development, such as in Pacific salmon species (Wootton and Smith, 2015)

Summary

Introduction

The Mediterranean region is a biodiversity hotspot for freshwater ecosystems, harbouring many species (many of them endemic) and genetically distinct lineages that are of conservation concern (Araguas et al, 2012; Sharda et al, 2018). One of these species is the three–spined stickleback Gasterosteus aculeatus, L. It is a small teleost fish and is a model organism in evolutionary biology and ethology (Bell and Foster, 1994; Mäkinen et al, 2006; Cresko et al, 2007; Mäkinen and Merilä, 2008). In the rest of Spain, they are limited to fragmented populations (Doadrio, 2002)

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