Wood-Devouring Clams Infest 100 Sunken Ships in Baltic Sea, Continue to Spread

Close up shot of driftwood with shipworm holes.

Alan / Flickr / CC BY-NC-ND 2.0

'Dreaded' Shipworm Can Devour a Shipwreck in 10 Years
The shipworm, which isn't a worm at all, is a maritime archaeologist's worst enemy. The unusual saltwater clam is known for boring into underwater wooden structures--eventually destroying them entirely. The shipworm can destroy an entire historical archeological site like a sunken ship in just ten years. Pretty impressive for a clam. It also commonly 'attacks' docks and piers. And now, thanks to rising ocean temperatures, it's spreading--researchers have spotted the shipworm in the Baltic Sea for the first time. Could it become a worldwide threat?According to Science Daily, the shipworm doesn't typically do well in waters with low salinity, and has historically avoided the Baltic for that reason. But now they've been spotting it along the Danish and German coasts, where it has already infested over 100 sunken ships in the area:

'The shipworm has for example attacked shipwrecks from the 1300s off the coast of Germany, and we are also starting to see its presence along the Swedish coast, for example at the Ribersborg cold bath house in Malmö,' says Christin Appelqvist, doctoral student at the Department of Marine Ecology, University of Gothenburg.

Appelqvist is part of the EU's WreckProject--an effort spearheaded by researchers from different European nations to determine which "archeological treasures are at risk." They've found that that warming waters may be behind the shipworm's spread. The scientists have found that "in short, the increased water temperature may help the shipworms to become adapted to lower salinity." Chalk up another adverse effect of climate change--the spread of ravenous, wood-devouring clams.

Now that the team has realized the threat it faces, it's now got to address how to save the historical sites from the shipworm. It won't be easy: there are an estimated 100,000 such sites in the Baltic Sea. The team is working on ways to protect them--perhaps by covering them in geotextile and bottom sediment, and perhaps by predicting where the shipworms will strike next.

It's hard to predict what the greater effect of spreading shipworms could be. But they could pose a very real--and very irksome--threat to piers, docks, and ports in general.