The distribution of Danish freshwater fishes (38269)

The objectives of this project are, for the first time in almost 100 years, to produce and in a book present an updated distribution map of all freshwater fishes found in Danish fresh waters. The results will act as a reference point when analyzing both previous and future changes in the distribution of freshwater fishes in Denmark, e.g. related to climatic changes.

Until the beginning of this project the geographic distribution of freshwater fishes in Denmark was not known in detail. For many species we only knew in which part of the country and maybe in which river system they live now or had lived earlier. Thus, our knowledge was incomplete and in general fragmented and consequently hard to find. In addition much of the existing information was old and newly arrived alien species had not been registered correctly. Thus, there was a needfor a complete and updated status on the distribution of freshwater fish Such a status will be a milestone in Danish inland fisheries research and management. Its value in relation to research and management as well as providing public access to correct information will be high. As an example the database has been used to revise the red data list for freshwater fishes in Denmark.

In this project we have 1) collected existing data on the occurrence of freshwater fish from public and private institutions and 2) gathered information from the public on catches and other observations of freshwater fish. As supplement we have 3) made targeted surveys to fill gaps and improve knowledge on rare species. All this information have been 4) combined in a GIS-based database. Finally we have 5) presented the complete set of information on geographical distribution of freshwater fishes in Denmark in a book also containing detailed information on the biology and ecology of all species (native and alien) present in Denmark.

The book was published in 2012 and contains 700 pages. It is written in Danish and illustrated with a large number of high quality photos of all species. It is written by 5 main authors (two of which are from DTU Aqua) and a few guests (one from DTU Aqua). Even though written to a broad audience, it is fully documented with references in the text. Due to private funding it has been possible to distribute the book at a very low price, 399 DKK (ca. 53 €). The revenue from the sale is reserved for a future revision and re-publishing of the book.

The project was coordinated by Natural History Museum of Denmark, University of Copenhagen, Denmark. The project was funded by Aage V. Jensen’s Charity Foundation.

Research area: Freshwater Fisheries and Ecology