Behavioral Interactions and Trophic Overlap between Invasive Signal Crayfish Pacifastacus leniusculus (Decapoda, Astacidae) and Native Fishes in Iberian Rivers

Iván Vedia,David Galicia,Jesús Santamaría,Javier Oscoz,David Almeida,David Elustondo,Amaia Rodeles,Rafael Miranda,Enrique Baquero,Pedro Leunda

doi:10.3390/w11030459

Iván Vedia, David Galicia + Show 8 more

Open Access

https://doi.org/10.3390/w11030459

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Journal: Water	Publication Date: Mar 5, 2019
Citations: 4	License type: CC BY 4.0

Affiliation: University of Navarra, Universidad San Pablo CEU

Abstract

The signal crayfish Pacifastacus leniusculus Dana, 1852 is a successful invasive species in the Iberian Peninsula. This is of particular conservation concern, as fish fauna is highly endemic and also threatened within this ecoregion. The aim of this study was to analyze behavioral interactions and trophic overlap between signal crayfish and native fishes in Iberian rivers (northern Spain). Video cameras were used to record fish “dominance/evasion” after spatial encounters with crayfish. Diet composition and isotopic signatures (δ13C and δ15N) were compared to evaluate the niche overlap. Fish were dominant in 25% of the encounters with juvenile crayfish, whereas this percentage was only 4% with adult crayfish. Observations showed a high fish “evasion” response for Pyrenean stone loach Barbatula quignardi (Bǎcescu-Meşter, 1967) (>30%). Dietary results showed a high trophic overlap between signal crayfish with the pelagic Pyrenean minnow Phoxinus bigerri Kottelat, 2007 and the benthic loach. However, the isotopic niche overlap was low, with brown trout Salmo trutta L., 1758 showing the highest area (only 0.1 ‰2). Overall, our findings suggest that interferences may occur with native species for food (i.e., benthic invertebrates). Consequently, measures should be applied to control invasive crayfish in Iberian rivers.

Highlights

Biological invasions are one of the most important causes of biodiversity loss at the global scale [1,2,3]
No association was observed between the result of the encounter and crayfish sex
The frequency of encounter categories significantly differed between juvenile Water

Summary

Introduction

Biological invasions are one of the most important causes of biodiversity loss at the global scale [1,2,3] This conservation concern is relevant across inland waters of the Mediterranean region in Europe [4], where endemic freshwater fish are highly threatened by invasive species [5]. The signal crayfish Pacifastacus leniusculus Dana, 1852 is native to North America and was introduced into the Iberian Peninsula from Sweden in 1974 for the purpose of expanding aquaculture [8]. In this region, signal crayfish were first introduced into the

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