Where do they go? Harbour porpoises unaware of borders.
An estimated 5-10.000 harbour porpoises dies annually in the Danish gillnet fishery. Concern has been expressed that this by-catch may not be sustainable. An abundance of about 300.000 harbour porpoises has been estimated in the North Sea and adjacent waters. Preliminary studies on population structure suggest the existence of several sub-populations, that could well be affected very differently by the geographically concentrated fishery.