“Watersipora subatra”, a long-distance traveler

Originally from Japan, Watersipora subatra gradually invading the oceans and seas of the globe. The introduction of a species into a new ecosystem can sometimes cause irreparable ecological imbalances. In the marine environment, their consequences can be serious due to the complexity of the intervention.

There are some striking examples, such as tropical green algae Caulerpa taxifolia in the Mediterranean or even the Kamchatka royal crab. These crabs, which originate in the Bering Sea between eastern Russia and Alaska, were brought to the Barents Sea to develop fisheries and support local employment. Finding favorable ecosystems, this species quickly expanded its range to the west and colonized the coast of Norway, now up to the Lofoten Islands. It poses a threat to the ecosystems it colonizes, the functioning of which it deeply disrupts, in particular by swallowing fish eggs, including eggs and cod.

Fortunately, in most cases the introduced species are more restrained, which does not preclude their monitoring in order to detect any disturbances in the functioning of ecosystems or the extinction of other species.

Mohanka Watersipora subatra illustrates the example of the restrained but very effective ability to colonize a new environment – which emerged in Japan, it spread widely along the coast of Brittany in just a decade.

If its arrival in Europe may be due to the presence of colonies in the saliva (young) of Japanese oysters, its expansion may also occur through the attachment of its larvae or colonies to the hulls (a phenomenon commonly referred to as “fouling”). ), or by drifting algae, which could develop colonies.

Various “foamy animals” around the world

Mohans, literally “moss animals”, are colonial animals, mostly attached to the substrate, inert or living, and mostly marine. Each individual, called a zoid or zoetia, lives in a millimeter-sized cell in a colony, a zoo, which can be inlaid, erect, or shrubby, and ranges in size from a few centimeters to several tens of centimeters. Nutrition and respiration of beetles is provided by the flow of water created by the crown of the tentacles, which is called “lofofor”. Because houses are often carbon dioxide, several species thus contribute to the construction of coral reefs in warm seas. The shape, size and location of the cameras allow you to recognize different types.

Due to their larvae or colonies, which are in “overgrowth”, some species are easily transported from port to port and are now colonizing the European coast.

Such is the case Watersipora subatra, native to Japan, is now registered as an introduced species in the Northeast Atlantic, the Indo-Pacific (Indonesia), the Southwest Pacific (Australia, New Zealand) and the Northeast Pacific (California). The taxonomy of this genus, which includes 13 species that are sometimes very similar morphologically, has led to many hesitations before finally identifying the Watersipora present on European coasts.

Along the European Atlantic coast, this species was first identified as Watersipora aterrima in the Arcachon Basin between 1968 and 1973, then as Watersipora subovoidea in Brittany in 2005, considered as Watersipora subtorquata in 2009. It is now known that the species present in Brittany, around the British Isles and in the North Sea are actually Watersipora subatra and that four other species are present on the rest of Europe’s coasts.

Leave a Comment

Your email address will not be published. Required fields are marked *