Invasive Species Threaten Marine Biodiversity in Danish Waters
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Loading... - Eva Reilly
- 16 Aug 2024
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Denmark's waters, fjords, and streams are facing a growing threat from invasive species, which can outcompete native species for resources and habitat, leading to a decline in biodiversity. While there are approximately 2,600 non-native species in Denmark, 77 of them are considered invasive, meaning they have established themselves in the environment and are causing harm to native flora and fauna or the economy.
The United Nations Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) has identified invasive species as one of the five drivers threatening biodiversity worldwide. In fact, invasive species are estimated to have played a role in 60% of cases where a plant or animal has become globally extinct.
In Denmark, four invasive marine species have been recorded, including the comb jelly Mnemiopsis leidyi and the round goby, a fish originating from the Black and Caspian Seas. The round goby was introduced into Danish waters through ship ballast water 15-16 years ago and has since established itself in the waters of southern Denmark.
Researchers at DTU Aqua have been studying the round goby and have found that it is a successful invasive species, capable of thriving in a variety of aquatic environments and outcompeting native species for food and habitat. However, little is known about the damage the round goby is causing to Danish ecosystems, and more research is needed to understand its impact.
To address the lack of knowledge about invasive marine species in Denmark, researchers at DTU Aqua have developed an underwater robot called ESP (Environmental Sample Processor) that can identify species using DNA analyses. The robot can operate in water for up to three months, taking samples of the water and identifying up to five different species. This technology has the potential to provide a wealth of information about invasive species in a cost-effective way.
The ESP is currently being used in a collaboration project with Iceland to monitor humpback salmon, an invasive species in Icelandic streams. In 2024, a third-generation ESP will be used in a project with Ørsted and the Danish Environmental Protection Agency to map the biodiversity of offshore wind farms at Horns Rev and Anholt in Denmark.
Invasive species can come at a high price for both the environment and the economy. In Denmark, Pacific oysters are spreading in the Limfjord and other areas, outcompeting native mussels and disrupting the ecosystem. The international researchers behind the IPBES report estimate that the global economic costs caused by invasive species in 2019 amounted to nearly DKK 3,000 billion.
Professor Jens Kjerulf Petersen from DTU Aqua is calling for an increased focus on reducing the spread of invasive species in Danish waters. "It's widely accepted that we can't get rid of invasive marine species. But we could limit their spread, just like we do with hogweed, Rosa rugosa, and the black rat. No one expects them to be eradicated completely, but we still spend considerable amounts on reducing the damage they do to our environment. We should do the same for our aquatic environment."
