[Invasive-species] Invasive freshwater spp Belgium

[VANDEN BOSSCHE Jean-Pierre]

Dear Colleagues,

In addition to the former messages and to be more precise about some recent exotic/invasive freshwater species in Belgium:

1. The "exotic" species Corbicula both spp., Atyaephyra desmarestii, Hemimysis anomala occurs in the river Meuse in Wallonia. Among these, Corbicula spp are "invasive" and "detrimental" (as well as Dreissena, Dikerogammarus spp, Hypania, for instance)

2. Gammarus tigrinus is "exotic" but does not seem to be "invasive"(at the present time). As well as Crangonyx pseudogracilis, it may vanish under the pressure of Dikerogammarus spp. First record in Belgium (Wallonia) at Petit-Lanaye in 1995 (Josens et al, 2005) on 9th Septembre 1995. Restricted, in Wallonia,  to the Meuse river.

3. I sampled personally Corbicula fluminea AND Corbicula fluminalis in the river Meuse, at Petit-Lanaye (Belgium, Wallonia), on 9th Septembre 1995, 1 pm.

4. The actual status of Atyaephyra, Hemimysis and Limnomysis is not easy to settle as these species are not easily caught with our current sampling devices and methods ("good luck" catches). Therefore, we should not conclude too rapidly to these species' statuts. 
 
In my opinion, we should be comprehensive and  include in the list all "exotic" (or "alien", "allochtonous",...) species, invasive as well as not (yet?) invasive, detrimental as well as not (yet?) detrimental. The settlement status can be indicated in the columns, as it is now .

Yours for more information.

Best wishes,

Jean-Pierre

Dr Jean-Pierre VANDEN BOSSCHE
Attaché scientifique, Chef de projet.
Centre de Recherche de la Nature, des Forêts et du Bois (CRNFB)
DGRNE, Ministère de la Région wallonne,
Avenue Maréchal Juin, 23. B-5030 Gembloux (Belgique)
Tél.: + 32 (0) 81 62 64 39  Fax: + 32 (0) 81 61 57 27
E-mail: jp.vandenbossche at mrw.wallonie.be
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