Accelerated invasion of decapod crustaceans in the southernmost point of the Atlantic coast of Europe: A non-natives’ hot spot?

Abstract

16 17 Observations of previously unrecorded non-native species in the Gulf of Cadiz (Spain), situated 18 between the Atlantic Ocean and the Mediterranean Sea, have accelerated since 1980, and 19 increased rapidly in the past five years. Four new records of decapod crustaceans have been 20 detected in this region: the African snapping shrimp Alpheus sp., the West African cleaner shrimp 21 Lysmata uncicornis, the Indo-West Pacific giant tiger prawn, Penaeus monodon, and the Atlantic 22 blue crab Callinectes sapidus. The introduction and establishment of these species into the coastal 23 waters of this region , the southernmost Atlantic coast of Spain may have been influenced by 24 recent anthropogenic alteration of habitat, particularly estuaries and salt marshes, and by climate 25 change facilitating the spread of warm water biota. 26 27 Introduction 28 29 Biological invasions may have accelerated as a consequence of expanded connectivity (Hulme et 30 al., 2017). The increase in shipping, both commercial and recreational, risks the transport of 31 ballast and biofouling assemblages (González-Ortegón et al. 2007; Cuesta et al. 2016; Galil et al. 32 2019). Climate change may enhance the establishment of introduced species, as well as the 33 poleward shift in distribution of numerous species over decades (Sorte et al. 2010; Canning-Clode 34 and Carlton 2017; Pinsky et al. 2020). The climate driven range shifting of West African marine 35 species northwards into European waters has been termed "African Creep" by Canning-Clode 36 and Carlton (2017). 37 38 Given the risk of invasion, predicting the population growth patterns of non-native species 39 (NNS) is imperative for effective management. We use NNS as an inclusive term for species 40 occurring outside of its natural range, whether it was introduced intentionally/unintentionally by 41 humans (non-indigenous species, NIS), as well as climate driven species (CDS) extending their 42 range naturally. 43 44 The Gulf of Cadiz (GoC), Spain, adjoining the Straits of Gibraltar, may be increasingly 45 vulnerable to introductions, both from the much-invaded Mediterranean Sea and through the 46 northward expansion of African biota, that is African Creep species (Cuesta et al. 2016; Canning-47 Clode and Carlton 2017; Galil et al. 2018; Guastella et al. 2019). Over the past four decades, the 48 southwestern coast of Spain has been transformed. Its four main harbours have been expanded 49 (Fremont 2007) -the port of Algeciras ranks first in Spain in container traffic volume, and second 50 among all Mediterranean ports (Acosta et al. 2007). Beaches have been reconstructed (e.g. in 51 Algeciras, Cadiz and Huelva), the Guadalquivir estuary made navigable at the cost of the adjacent 52 salt-marshes (Del Moral Ituarte 1991), and the Guadiana and the Guadalquivir dammed (Clavero 53 et al. 2004; Morais 2008). The massive coastal sprawl, changes in water-usage and dynamic flow 54 characteristics of the main rivers, in addition to climate anomalies may facilitate invasions (Duarte 55 et ...

Anthropogenic Modifications to Estuaries Facilitate the Invasion of Non-Native Species

“…Finally, climate warming will expand northward along the European Atlantic coast through the gulf of Cadiz and will benefit non-native species with wide environmental tolerances, as has already occurred with other macroinvertebrates [1].…”

“…New worldwide observations of non-native invasive species (NIS) have increased over time, for instance in the Gulf of Cadiz (Spain), GoC, since 1980 and even more in the last five years [1]. Although the rate of new observations cannot be relied upon as an indicator of introduction rate, due to such factors as: sampling bias, occurrence of unexpected discoveries, lag time between introduction and discovery, and high variability in sampling effort, it does indicate increasing pressure on the GoC.…”

Free Pass Through the Pillars of Hercules? Genetic and Historical Insights Into the Recent Expansion of the Atlantic Blue Crab Callinectes sapidus to the West and the East of the Strait of Gibraltar

“…The most prominent humanmediated dispersal vectors in aquatic ecosystems are intentional introductions, aquaculture, and shipping/boating (e.g., ballast water, hull fouling) (Gollasch, 2006;González-Ortegón et al, 2007;Cuesta et al, 2016). The invasion of exotic species is being accelerated worldwide as a consequence of expanding transport and commerce (Mack et al, 2000); for instance, non-native species have been reported in the Gulf of Cadiz since 1980, but have increased rapidly in the last five years (González-Ortegón et al, 2020). The so-called Atlantic blue crab Callinectes sapidus Rathbun, 1896, a species native to the western Atlantic Ocean, is a good example for the introduction and fast growth of new non-native populations in the Euro-African area (Nehring, 2011;Mancinelli et al, 2021).…”

“…On the western coast of the Iberian Peninsula, the first record dates back to 1967 in the Tagus Estuary (Portugal), but only a few sporadic records were made since then in this region (Encarnação et al, 2022). Along the Mediterranean coast of the Iberian Peninsula, the first record was made in the Ebro Delta in 2012-2013 (Castejón & Guerao, 2013), and since then its distribution expanded rapidly towards the Strait of Gibraltar where it has been registered since 2017 (Cabal et al, 2006;Nehring, 2011;Mancinelli et al, 2017a;Mancinelli et al, 2017b;González-Ortegón et al, 2020;Mancinelli et al, 2021). In the Gulf of Cadiz, the first published record of Atlantic blue crab dates back to 2016 (Morais et al, 2019), however, a male adult specimen was already collected in the Guadalquivir Estuary in 2002 (Rodríguez & Cuesta, unpublished data).…”

“…Considering these genetic data, and the fact that adult blue crabs have a considerable ability to swim and travel up to hundred kilometers (Kara and Chaoui, 2021) or the high fecundity of females, which would allow the passive transport of a huge amount of larvae by oceanic currents between the Mediterranean Sea and the Gulf of Cadiz, it is more likely that the populations of C. sapidus in the Gulf of Cadiz and Alboran Sea result from the expansion of the species along the Mediterranean Sea -single introduction -or to a secondary introduction event within the invaded range. For example, the timeline of the first reports along the southern coast of the Iberian Peninsula were made sequentially from the east to the west, between the Ebro Delta and the Gulf of Cadiz, in just seven years (Castejón & Guerao, 2013;Morais et al, 2019;González-Ortegón et al, 2020;Encarnação et al, 2021). Additionally, the haplotype diversity is extremely low between populations -only two haplotypes are present.…”