Investigating coastal fish stocks and fishery opportunities at the west coast of Denmark (Vesterhavsfisk)

Background: West coast of Denmark used to be an important fishing area in previous decades. Fishers in the area have reported declines in local fish populations and fishing vessels have been reduced in numbers. Fishing is taking place further North, in Skagerrak, or further offshore. Such observations were also confirmed by previous scientific projects in the area. Nevertheless, stocks in the North Sea have been rebuilding and there is a question if the coastal areas will also see an increase in population sizes of important commercial species.

Aims of the project: Given the situation in the area, the Vesterhavsfisk project has as a main goal to investigate important species distribution changes and evaluate potential fishing opportunities in the area. The aims of the project are to i) collate existing knowledge from previous studies in the area, ii) gather new information from 2 scientific surveys along 3 transects off the Danish west coast and one transect in Skagerrak, iii) recruit commercial fishers to conduct experimental fishing using commercial style gillnets along the same transects, iv) collect stomach contents from plaice and benthic samples to investigate feeding preferences of the species along the different transects and, v) evaluate the potential of re-establishing the area as commercially and biologically sustainable fishing grounds.

Results: Commercial species were caught during the Havfisken survey, but the sizes indicate that the coastal area is mostly used by juvenile populations that are not interesting commercially. The number of fish caught during the gillnet experimental fishing were too low confirming that the area is not a viable fishing area. Stomach and benthic analyses for plaice showed differences in the feeding behaviour of the species and the faunal biodiversity from North to South. Changes in environmental conditions, like increasing temperatures closer to the shore have caused important commercial species like cod to stay away from these coastal areas during their adult stages, as they are outside their temperature tolerances.

Conclusion: The available information prior to this project, as well as the investigations carried out throughout its duration, confirmed previous observations of low commercial fishing opportunities in the area. The investigations give some first insights of the environmental conditions that lead to the decline of the populations, but the investigations should continue to be able to make sound scientific conclusions.