Finland Times

 

File Photo – Lehtikuva.

Finland is now a thriving home for crabs. At the bottom of the Archipelago Sea, there are plenty of round-shelled Zuiderzee crabs, which had previously only appeared on nature programmes. 

 

The first specimen was found in Finnish waters in 2009.

 

“The Zuiderzee crab has now virtually spread to the whole of the Archipelago Sea, excepting only the outermost parts. The progress is being made at a rapid pace on the Sea of Bothnia side,” said Tiia Forsström, a biology department student at the University of Turku, in a PhD dissertation.

 

The northernmost sightings are between Uusikaupunki and Rauma, and the most southerly is on the west side of Kemiönsaari.

 

The adult crab can walk, but at the larval stage it’s more like plankton. When ocean currents are suitable, the larvae migrate rapidly.

 

In addition to the university’s own research on crabs, information has also come from fishermen. 

 

The crabs have been found in stomachs of perch, and the crabs sometimes get caught in fish traps and nets. Sandy beaches also show the aftermath of shell molting.

 

“The carapace of the largest specimen is only two and a half centimetres, so they can’t really be used as food by people,” the researcher said.