Biodiversity and migratory fish

Worldwide, about 33,000 fish species are described. Out of these, about 7,000 are used for human consumption - and the trend is upwards. The identification of these species is often based on single morphometric characteristics and usually requires expert knowledge. However, as well with regard to product quality and consumer protection as for the traceability of fish and fish products for stock conservation issues it is necessary to unambiguously identify fishes and to verify their origin. This applies also for already processed fish products like e.g. filets and canned goods, where a control of labelling must be possible. At the Institute of Fisheries Ecology our expertise in fish identification, laboratory analytics and fish genetics enables us to work on the development of genetic markers for species identification and stock separation of important model species like sprat and herring, but also icefish and tuna. Migratory fish species represent an important and, in terms of biology, particularly interesting part of the aquatic species inventory. To reach their spawning and feeding grounds many fish species make long and exhausting migrations, during which some cover enormous distances and overcome great obstacles. Among these, species that migrate between fresh and saltwater, so called diadromous species, are often particularly vulnerable to anthropogenic impacts, such as river barriers, overfishing or climate change. This leads to special challenges for stock management, often associated with the international coordination of protective measures and strategies for a sustainable use. At the Thünen Institute of Fisheries Ecology we explore a variety of questions regarding biology, ecology, behaviour, protection and use of ecologically and commercially important migratory fish species. A main area of our research is the investigation of the different life phases of the European eel (Anguilla anguilla), whose stock is deemed to be outside safe biological limits for years and considered as endangered. We conduct field and laboratory studies in order to better understand the life cycle as well as the stock affecting factors and mechanisms and thus develop the basis for a sustainable stock management of this species.