First record of the Asian copepod Pseudodiaptomus marinus Sato, 1913 (Copepoda: Calanoida: Pseudodiaptomidae) in the southern bight of the North Sea along the coast of France

Abstract

The nematode Anguillicoloides crassus is one of the many threats hanging over anguillid eels, now known to infect six Anguilla species worldwide. It was first described in Japan, in 1974, and is commonly thought to natively stem from East Asia. Here our primary objective was to critically evaluate this long-held statement. We first retraced the factual history of this global invader, to later investigate the pros and cons for an East Asian origin. After exploring the alternative scenarios for the joint origin of the two anguillicolid parasites occurring in this area, we concluded that the geographic zone covering the natural range of the local eel A. japonica is still the most probable origin (in the absence of another identified candidate host and area). However, we cannot exclude that A. crassus may have been previously introduced along with exotic eel species, at some early stages of aquaculture in Japan. We call for caution when dealing with the native origin of this and other parasitic invaders in provenance of East Asia, a region to be regarded as a major crossroads for fish and parasites of the world. We finally identified the need for a possible resolution of the question, which includes a deeper sampling effort in the Indo-Pacific zone and the further development of molecular phylogeographic studies of all five anguillicolid species and their hosts.

First report of the planktonic copepod Oithona davisae in the northern Wadden Sea (North Sea): Evidence for recent invasion?

“…Thus, we suggest that O. davisae was most likely transported via ballast water tanks into the North Sea. This is also congruent with the findings for the other four introduced planktonic copepod species (Brylinski 1981;Seuront 2005;Brylinski et al 2012). However, all other four species were first found in coastal waters of the southwestern North Sea near big harbours, while O. davisae was found in the northeastern Wadden Sea.…”

“…Within the six species, only two copepods were recognised: the calanoids Acartia tonsa and Eurytemora americana. Apart from these records, two other calanoid copepods have been identified from the southwestern North Sea: Acartia omorii (Seuront 2005) and Pseudodiaptomus marinus (Brylinski et al 2012, Jha et al 2013. It is assumed that the introduction of these species is most likely related to ballast water discharge (e.g.…”

“…It is assumed that the introduction of these species is most likely related to ballast water discharge (e.g. Gollasch et al 2009;Brylinski et al 2012).…”

Spreading factors of a globally invading coastal copepod

“…1) and in the North Sea, that is, in the harbor of Calais (France) (2010) and along the coast off Gravelines (France) (2011) ( Fig. 1) (Brylinski et al, 2012). The species was recorded in the afore mentioned sites in different periods of the year; however, to date it is not possible to assess whether P. marinus is still present there.…”

“…It is present in the estuary of Bilbao along the Atlantic coast of Spain since 2010 (Villate, personal communication). It was signaled further north in the Bay of Biscay, near the Gironde estuary (France) (Brylinski et al, 2012) (Fig. 1) and in the North Sea, that is, in the harbor of Calais (France) (2010) and along the coast off Gravelines (France) (2011) ( Fig.…”