Sea vomit - risk to Norwegian biodiversity


Report no:

Publishing: 30.01.2023

Key message:

VKM shall assess the risk the invasive marine tunicate “sea vomit” can pose to biodiversity in Norway, should the species spread in Norwegian waters.

VKM will also assess the possible negative impact on marine aquaculture.

The assessment has been commissioned by the Norwegian Environmental Agency.


Sea vomit, also known as Japanese carpet sea squirt, was first discovered in Norway outside of Stavanger November 2020. Thus far the species has been found in 26 different locations in Rogaland and Vestland, according to the Norwegian Biodiversity Information Centre.

Sea vomit is an alien invasive species, native to the Pacific Ocean. The Norwegian Biodiversity Information Centre classified it as a door-knocker species in 2018 with a high likelihood of invasion and of ensuing severe negative ecological effects. Additionally, sea vomit can have a strong negative impact on marine aquaculture.


In order to prioritize measures that can reduce the consequences the presence of sea vomit in Norway might have because of its establishment here, the Norwegian Environmental Agency needs to know more about it. In addition to assessing risk, VKM is asked to identify and assess various risk- reducing measures and to propose the most effective combinations of these.

The project consists of two stages. In stage one the focus will be on identifying measures that can be implemented in a short time frame (1-3 years). The second stage will include a full risk assessment and evaluations of long-term measures.

Project group

The project group consists of:

  • Johanna Järnegren, VKM Panel on Alien Organisms and Trade in Endangered Species (Chair of the project group)
  • Vivian Husa, external expert, Institute of Marine Research
  • Bjørn Gulliksen, external expert, University of Tromsø
  • Eivind Oug, external expert, Norwegian Institute for Water Research
  • Martin Malmstrøm, VKM Secretariat, Project Manager

The assessment will be approved by the VKM Panel on Alien Organisms and Trade in Endangered Species (CITES). The report from stage one should be finished by the end of March 2022. The second stage is to be completed by a


The Norwegian Scientific Committee for Food and Environment

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