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Shipworm docks at the harbor

Shipworms love eating wood. That could spell trouble for many cultural heritage sites underwater. FOTO: Bjørn Altermark

Shipworm docks at the harbor

A pest that's a menace to cultural landmarks is captured near Longyearbyen.

It looks like a worm, but is a type of shellfish that can do enormous damage to all wood in the sea, including docks, boats and cultural heritage sites, said Bjørn Altermark, a researcher for the Department of Chemistry at the University of Tromsø (UiT).

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Researcher Bjørn Altermark captured the shipworm by the docks in Longyearbyen. FOTO: Seila Pandur

Shipworms are not terribly fond of cold water and the northern limit of its distribution has typically been the coast of Finnmark. Observations in Svalbard have historically been extremely rare.

In an attempt to find out the current situation up here in the north, Altermark last year deployed wooden planks into the sea near Bykaia in Longyearbyen. More than one year later, he returned and knocked on the proverbial door. There was someone at home.

"At the first ax blow in the plank that lay at the top of sea we found a shipworm," Alternark said. "It was 15 centimeters long. The rest of the planks were not infected."

Northerner?

The animal is the species Psiloteredo megotara, the same as those living in northern Norway. It can be about a meter long and thick as a finger. The cold water in Adventfjorden probably did not give this specimen optimal growth conditions.

"It has not grown as fast as those on the mainland coast," Altermark said.

Jørgen Berge, a biology professor at UiT, called the rare discovery intriguing.

"We have been waiting for it," said Berge, who has sought out shipworms in Svalbard for many years. "We know that the climate is changing and there will be other species coming from the south. Shipworms are one of them."

"Since 2007 we have regularly laid out pieces of wood in Kongsfjorden and Rijpfjorden, but never found a trace of them," Berge said.

Whether the specimen discovered in the harbor was just a lonely soul who strayed into uncharted waters or is one of many trying to settle down in Svalbard is not yet known. Nor how it ended up here.

"It might, for example, have come with a wooden boat, ballast water or followed the currents from the Norwegian coast and up," Altermark said.

Wood lovers

For shipworms, all things wood are good.

"Eating woodwork is its life. As larva, it swims free. But once it establishes itself on a piece of wood, the shell parts develop. These are used to rasp inwards with and, once he is inside, he is there all his life and eats," said Altermark, whose daily research focuses how they are able to digest cellulose.

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The captured shipworm. FOTO: Bjørn Altermark

The pier in Longyearbyen is made of steel and concrete, according to Harbormaster Kjetil Bråten, who therefore isn't going to lie awake at night after hearing about the uninvited guest in the fjord.

It is more difficult for underwater cultural heritage shipwrecks.

"There is a plethora of wrecks around that have not been found," said Snorre Haukalid, a cultural heritage advisor for The Governor of Svalbard. "Written sources suggest that there may be hundreds."

Cultural momument vandals

An invasion of shipworms may even eat through a shipwreck in a matter of decades.

"If the climate warms and they come it's only a matter of time until otherwise intact ships disappear," said Øyvind Ødegård, a marine archaeologist and PhD student at the Norwegian University of Science and Technology in Trondheim.

In September of this year, he started a research project to investigate the pest in Svalbard.

"I've put out samples of oak in Kongsfjorden and Rijpfjorden, both at the surface and at the bottom," he said. "This wood is very similar to what you find in ships from the 1600s onwards and it will be checked for shipworms every year in the future."

The choice of measurement sites was not random. Kongsfjorden is located on the west side of Spitsbergen and is dominated by warm water from the Atlantic Ocean. Rijpfjorden is north in Nordaustlandet and contains colder Arctic waters.

"It will be interesting to see if attacks are limited to certain areas," Ødegård said. "It is warmth that offers a welcome to shipworms, so the hope is that it is not as widespread so far north."

So far, he said he does not believe the pest is a major problem in Svalbard.

"It was found in some pilings that were salvaged from the old coal pier," he said. "In addition, we found traces on a wreck in Trygghamna, but it was not really attacked. There is the presence of shipworms here, but it is modest."

Translated by Mark Sabbatini

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