During seabed research in the North Sea Canal, a new, exotic sea snail was discovered. The snail probably comes from the northeastern United States and ended up in coastal waters in North Holland via international sea freight.
Two live specimens of a snail that has never been found in our country. That is what Olaf Duijts, researcher at Bureau Waardenbrug, found during a soil survey last October, within the sampling program of Rijkswaterstaat: “I know what the species we know looks like, so I immediately thought: what kind could it be? “
The houses have clear characteristics of the snail family Pyramidellidae which has many thousands of species and originates worldwide. Mainly because of the tower-shaped shape and the opening of the shell. One of the two ‘Dotted line horns’ was an almost adult 3.2 mm, and the other a damaged juvenile.
broke channel
It is not the first time that a new species has been discovered in the North Sea Canal, says Duijts. “It is a brackish canal, which opens up the harbor and where fresh and salt water mix. Very specific species occur, partly because the salinity can vary.”
In addition, ships arrive all over the world. Duijts: “It is actually not the intention for fauna to be shipped around the world, but we see that international sea freight can be a source of the introduction of a new species.”
Duijts explains that exotics attach themselves to the outside of the ship or are in the so-called ‘ballast water’. “When an empty ship starts sailing, ballast water is pumped in to get the correct depth. That water can contain larvae or eggs. When the ship takes cargo in a harbor, the ballast water is pumped away.”
To survive
According to Duijts, it seems for the time being that the snails come from North America: “But we will only know for sure after DNA evidence.” If the two snails survive and settle here, then according to Duijts, there are various scenarios that can be envisaged: “Either they will increase in number and can threaten native species, or they are invasive for a certain period, then decrease in numbers and can exist next to native species. Or they don’t make it and quickly disappear again. But it’s too early to say anything about that now.”