Northernmost record of the pantropical portunid crab &lt;em&gt;Cronius ruber&lt;/em&gt; in the eastern Atlantic (Canary Islands): natural range extension or human-mediated introduction?

José A González,RaüL Triay-Portella,Aitor Escribano,José A Cuesta

doi:10.3989/scimar.04551.17b

Northernmost record of the pantropical portunid crab <em>Cronius ruber</em> in the eastern Atlantic (Canary Islands): natural range extension or human-mediated introduction?

José A González, RaüL Triay-Portella + Show 2 more

Open Access

https://doi.org/10.3989/scimar.04551.17b

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Abstract

The pantropical crab Cronius ruber (Lamarck, 1818) (Brachyura: Portunidae) is recorded for the first time from the Canary Islands. Previously known from off Cape Verde Islands and Senegal, this is the northernmost record of the species in the eastern Atlantic Ocean. Crabs have been caught by means of a collecting small trap for sampling in shallow waters, and then identified by both morphological characters and DNA barcoding (16S). Cytochrome c oxidase I partial sequence has been obtained for this species for the first time. This relatively large and very aggressive crab species seems to be rapidly occupying both hard substrates (sublittoral caves) and soft substrates (sand with seagrass meadow) adjacent to shallow rocky bottoms, at depths between 2 and 10 m, in the warm southern waters of Gran Canaria Island. The reasons for this species’ occurrence are discussed herein. Among them, natural range extension may be a consequence of tropicalization in the eastern Atlantic. Also, a human-mediated introduction could be based on the heavy traffic of ships (ballast waters or oil platforms) arriving at the Canary Islands from African countries and from Brazil in the last decade.

Highlights

Crabs have been caught by means of a collecting small trap for sampling in shallow waters, and identified by both morphological characters and DNA barcoding (16S)
Natural range extension may be a consequence of tropicalization in the eastern Atlantic
A human-mediated introduction could be based on the heavy traffic of ships arriving at the Canary Islands from African countries and from Brazil in the last decade

Summary

Introduction

After decades of ocean warming, an increasing number of works have postulated a tropicalization of species assemblages in temperate biogeographic transition zones such as southwestern Australia (Wernberg et al 2016), some parts of the Mediterranean (Horta Costa et al 2014), the NW of the Iberian Peninsula (Cuesta et al 2016) and the Macaronesian archipelagos in the northeastern Atlantic (Brito et al 2005, Wirtz et al 2008, Afonso et al 2013). The Canaries are geographically located on a very important maritime route, and both ships (Brito et al 2011, González et al 2012) and oil platforms (Triay-Portella et al 2015, Pajuelo et al 2016) have been recognized as major vectors for the introduction of non-indigenous species

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