The European flounder in Iceland

As part of her PhD Theresa Henke examines the distribution, introduction pathway and utilization of flounder in Iceland

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Until 1999, the flounder had not been reported in Icelandic waters. The first recorded flounder was caught near the mouth of the river Ölfusá and was identified by the Marine and Freshwater Institute. Since then the population of flounder has spread rapidly around the country. It has not clearly been identified how the flounder got introduced to Iceland, but it is hypothesized that the presence of flounder might have negative impacts on native fish species. Juvenile flounder occur in the same areas as juvenile plaice and adult flounder overlap with native salmonids. Flounder is considered as a potentially invasive species. Invasive species are those species, that are introduced into new areas through human action and eventually have negative impacts on the new ecosystem. Common pathways for invasive species to enter new regions include the transport of species via ballast water of ships and the intentional and accidental introduction when species are handled in relation with aquaculture and fisheries.

Economic value of the flounder

In the northeast Atlantic, including the North Sea and the Baltic Sea, flounder belongs to the commercially harvested species. It is mainly caught in coastal fisheries with gillnets and trap nets but often ends up as by catch in other fisheries. Flounder is also known as a popular sportfish in Europe. In England, flounder has been valued by recreational fishermen, both beginners and experienced, because of its availability in shallow water. The flounder has been described as “ready to take the bait”. In the northern part of the Baltic Sea the recreational fishery of flounder is considered substantial. In adjacent countries such as Sweden, Finland and Estonia, recreational catches can be around 30% of commercial catches or even exceed these.

The goal of this project

With this project we aim to increase the knowledge about the flounder in Icelandic waters. In a first step we want to collect data about the current distribution of flounder and people´s experiences with it in Iceland. Furthermore, we will examine potential introduction pathways of the flounder. With new species arriving in ecosystems it is important to understand and manage potential impacts.

If you are interested in recreational fishing or river management you can help with flounder research in Iceland by filling out this short survey.

Important resources:

Skerritt, D. J. (2010) A review of the European flounder Platichthys flesus – Biology, Life History and Trends in population.

Bax, N., Williamson, A., Aguero, M., Gonzalez, E., & Geeves, W. (2003). Marine invasive alien species: A threat to global biodiversity. Marine Policy 27(4): 313-323