A new amphipod species, known as killer shrimp (Dikerogammarus villosus), which has widespread in Europe has now been found in Finnish water at the Port of Rauma, said the Finnish Environment Institute (SYKE) on Thursday.
The species is well studied in Europe and poses a threat to invertebrate species, especially in brackish waters, but also in inland waters.
The killer shrimp reduces or displaces native species through effective predation and competition, thus reducing aquatic biodiversity.
The species now found in Rauma has spread to coastal waters in Europe from the Black Sea and Caspian Sea region, in the 1990s and, in the 2000s, also to many inland waters.
The nearest occurrences are from the coasts of Latvia, Lithuania, Poland and Germany, as well as from lakes in Sweden and Denmark.
The spread of the very drought-resistant killer shrimp can be prevented by treating ships’ ballast waters and washing the hulls, ropes and other water-contact equipment of vessels, including small boats, when moving from one water body to another.
Also, water of at least +50 degrees has been found to be sufficient to eliminate killer shrimps.
Last year, a new non-indigenous amphipod Melita nitida, was found at the Vuosaari Port. This year it has also been observed at the Port of Naantali.
No observations of this amphipod have yet been made elsewhere in the northern Baltic Sea.
The closest observations are from the Gdańsk Bay of Poland and the Danish Straits. The amphipod Melita nitida originates from the brackish water bays in North America.
It settled on the Atlantic coast side of Europe in the early 2000s. So far, there is no research data on the harmfulness of the species.
The species continue to spread through small boats. For example, the small tanaidacean crustacean (Sinelobus vanhaareni), first observed on the Finnish coast in 2016, has since been found in large numbers in samples taken from the hulls of recreational boats and at marinas.
This tanaidacean crustacean can already be found in densities of thousands per square meter.
To prevent the spread of non-indigenous alien species, it is important that all boaters treat and clean their boat hulls.
- Killer shrimps
- Found
- Finland
Source: www.dailyfinland.fi
