This crab does not belong in Norway – many other harmful species may soon arrive – Dagsavisen

– Both male and female crabs have been found, so perhaps that means Asian shore crabs have now been established here, says researcher Vivian Hossa of the Institute of Marine Research.

– In other countries, these crabs have become very numerous. They eat mold and decomposition on the beach and can compete with our own species, both crabs and fish.

Each female crab of this species can lay up to 50,000 eggs three to four times a year, according to the USGS-USGS. In the United States, Asian shore crabs were first found in 1988. Since then, their numbers have increased steadily, while the number of shore crabs native to the United States has declined.

In 2018, the latest Fremmedartslista to date was released. In August, the Species Data Bank will release a new edition of this list, with an overview of the exotic species most likely to establish themselves in our nature in the long term.

The list of “sprocket species” that can cause significant damage to Norwegian nature can be long.

– The number is much higher than we were aware of in 2018, says Olga Helmo, senior advisor at Artsdatabanken.

Kindergarten found her

– It started last fall. Then the children found a crab, which we didn’t understand, in Kjerkvågen, says child and youth worker Kjetil Windsland at the Spangereid Nature Nursery in Lindesnes municipality in Agder.

– My boss, who follows the Naval Research Institute on Facebook, got an article on his feed and tagged me in it, Windsland continues.

The article was about the cancerous brush. Wendsland then contacted the Naval Research Institute to obtain confirmation that it was just such a crab that kindergarten children had found. But when researcher Vivian Hossa answered, she could say it was an even more amazing discovery.

The crab turned out to be an Asian lobster, a species not previously detected in Norway.

– Since then, she’s been visiting the nursery regularly in Kjerkvågen looking for crabs, and today – out of the blue – we found two, says Wendsland.

This happened on June 13th.

– What did you do with the crabs?

– We’ve put it in the freezer, ready to be picked up by the Naval Research Institute, answers Windsland.

[ Dette er Oslos største turistproblem ]

New types of fish are waiting for you

– Asian crabs are also found in Bestumkilen in Oslo – also by a nursery, says Vivian Hossa.

– When did that happen?

– It was last year, right after the first discovery. So this crab may now have been established in several places. The same applies to the brush crab, which was found for the first time in Norway in 2020 – in Tjøme. Now it has spread to the Oslofjord.

Many other exotic species have also arrived in Norway in recent years, becoming in part an epidemic and a nuisance. Examples include Pacific oysters, harbor sparrows, and red algae devil’s tongue.

Puke salmon is an exotic species that has been in Norway since the 1960s, and is now caught from the border with Russia in the north, to the border with Sweden in far southern Norway, according to the Norwegian Institute of Natural Sciences.

Hosa thinks more may be in store soon.

– On the west coast of Sweden, there is a black-mouthed goby. We are waiting for him “any time”. It may already be here.

The black-mouthed goby is a fish that can grow up to 25 cm in length. They are naturally native to the Black and Caspian Seas, according to the Species Data Bank. Since the 1990s, the black-mouthed goby has spread over large areas in Europe, Asia and North America with the help of ship traffic and canals, notes the Institute of Marine Research.

[ Fire branner daglig i naturen: – Skogbrannfaren vil øke ]

Many types of door sills

It is an ancient phenomenon that foreign species are establishing themselves in Norway.

– An alien species is a species that has been helped to get here, for example by accompanying ships’ ballast water, or being present with imported goods. There are a number of different ways to spread, says Olga Helmo, senior advisor at Artsdatabanken.

– In the 2018 Exotic Species List, 1,532 species are assessed for risk, and most of the species – 1,199 – are already established in Norway.

Helmo points out that the true number of alien species found in this country is “much higher”.

– We’re not taking the risk of evaluating alien species that really existed before 1800, you say.

The new, fourth editions of Fremmedartslista will be published on August 11, after extensive preparatory work that involved a lot of experience. This time, Artsdatabanken has invested heavily in door sill types.

Door types are the ones that are very likely to establish themselves in our nature in the long term. They don’t breed outdoors in Norway right now, Helmo explains, but we think they will.

– We examined 3,400 species from all over the world, to see if they could survive and establish themselves in our climate. We found that more than 1,000 species could eventually establish themselves here, and all of those risks have been assessed. This is a significant change from 2018, when “only” 319 species were assessed for risk.

– We have a 50-year perspective on this, but the genre can change quickly from being one close to being well-established in Norway, Helmo continues.

Remember shelter vomit as an example.

– In 2018, Harbor Spum was not known in Norway and was considered an open species. Now this type is the challenge that the authorities are trying to prevent from spreading.

[ Lanserer «redningspakke for naturen»: – Vi står i en akutt naturkrise ]

Hit the crab warning

– How many species can cause so much damage?

– I can’t say anything about it yet. But I can say that the number is much higher than we were aware of in 2018, Helmo replies.

– Alien species list 2023 will give us the answer. We then have a better overview of the doorstep maps. We know who they are and we know the damage they can do to nature.

On the list of exotic species still in effect for 2018, 25 are in the “very high risk” category.

Among those evaluated in this way five years ago was Hemigrapsus sanguineus, more commonly known as the Asian lobster – not least to Lindesnes’ kindergartners. Another 29 doorstep species end up in the “high risk” category of the 2018 alien species list. Another 22 are “potentially high risk,” says Helmo.

– indicate that plants, fish, birds, mammals, and amphibians are among the species that live on the doorstep.

– What are the consequences if new types of door handles settle in Norway?

“Some sill species will be completely non-problematic, like other exotic species, but others can cause great harm to nature,” Helmo replies.

Many alien species are spreading rapidly and are highly competitive. Thus, the species that belong here will outpace the competition. From time to time, endangered species on the Red List are also affected. Hence it is also the case that many exotic species can carry diseases that can be transmitted to both agricultural species and wild species in nature.

– It’s also worrying that some alien species could interbreed with closely related species that are naturally found here, so we can get genetic contamination.

More knowledge about the types of doorsteps, who they are and what damage they cause gives authorities a better starting point for preventing the spread of those that cause significant damage to nature, Helmo points out.

[ Offentlig domangel: Måtte gjøre fra seg i ei bøtte ]