Neutral sources say that the average damage is 1 to 4% of the total yield. Other studies show that all Harbour seals together consume less than (1-2%) what the fisheries bring on land. All numbers are that low that it would be wise for fisherman tolerate the seal the enjoy area protection under the following laws:
In European waters, the harbour seal and grey seal fall under protection of the EU Habitat Directive (Appendix ll and V), the Bonn Convention (Appendix ll) and the Bern Convention (Appendix lll).
There is a long EU seal history. A Seal Covenant was signed in 1988 in Bonn, Germany. This treaty between the three Wadden Sea countries, The Netherlands, Germany and Denmark, regulates the protection of the seals in the Wadden Sea. Most famous is the EU Seal puppy directive