Without prejudice to regulation 2 and subject to paragraph (4) hereof, no twine forming all or any part of the sides of the meshes of a net used in fishing for or taking salmon shall have a mean thickness (measured in accordance with this regulation) in any part of its length of less than 0.9 millimetres.

In this regulation, “mean thickness” shall be the arithmetical mean of twenty measurements of thickness taken at random along a continuous length of at least 300 millimetres of the twine.

Twine shall be measured for the purposes of this regulation only when wet and held taut and no measurement shall be taken of any part of the twine which is, or has been, occupied or distorted by a knot.

This regulation shall not apply to any poke net used in fishing for or taking salmon under a certificate of privilege issued under the Solway Salmon Fisheries Commissioners (Scotland) Act 1877.