The establishment of European flounder (Platichthys flesus) in Icelandic waters

• Main Author: Henke, Theresa
• Other Authors: Guðbjörg Ásta Ólafsdóttir, Líf- og umhverfisvísindadeild (HÍ), Faculty of Life and Environmental Sciences (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands (HÍ), University of Iceland (UI)
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Iceland, School of Engineering and Natural Sciences, Faculty of Life and Environmental Sciences 2025
• Subjects: European flounder; Biological invasions; Interdisciplinariy; stakeholder involvement; Culturomics; Public Perceptions; Flundra; Líffræðileg fjölbreytni; Líffræði; Doktorsritgerðir; Faroe Islands; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/5194

Biological invasions are a global phenomenon representing one of the biggest threats to biodiversity. Addressing species introductions, often marked by context dependency, requires the incorporation of multiple perspectives and disciplines to develop adequate management approaches. As humans are involved on multiple levels along the invasion process, this should furthermore encompass the consideration of human dimensions. European flounder (Platichthys flesus), a flatfish species native to western Europe, has been documented in Iceland since 1999. In the following years, European flounder rapidly spread and now mainly occurs in estuaries but is often encountered in freshwater habitats. Here it spatially overlaps with native salmonids which represent valuable recreational species, making the recreational angling community in Iceland an important stakeholder group. The overall goal of this thesis was to integrate interdisciplinary approaches to address specific aspects of the establishment of alien European flounder in Iceland, including its geographic origin, distribution, and public perception. Additionally, the thesis aimed at using alien European flounder in Iceland as a case study to address larger-scale questions in the field of invasion science. In this thesis, the most likely origin of European flounder was identified as the Faroe Islands, utilizing microsatellite analysis. Following these results that revealed uncertainty concerning whether the species was introduced due to human activity or arrived naturally, the views of stakeholders and specialists concerning this uncertainty were assessed, indicating that the identification of a species’ introduction pathway is considered important but not prioritized over impact assessment and the development of management strategies. Involving the recreational angling community as a representative stakeholder group in the research has shown that European flounder is perceived highly negative but has furthermore highlighted spatial and temporal fluctuations in ...