Ohio Rev. Code § 1533.52
Except as provided by division rule, the size of the mesh of all nets, seines, and carp apron, except dip nets or minnow nets, possessed in this state or used in fishing in any of the waters of this state wherein fishing with nets is licensed by law shall be determined by measuring the mesh on the bar, by exerting not more than a two pound strain on four consecutive bars and measuring these four bars while that strain is on them from the inside edge of the knot on one end of this series of bars to the outside edge of the knot on the other end. One-half the length of the four bars so measured shall be deemed to be the length of one collapsed stretched mesh of that part of the net being measured. The weight to be used in measuring the bars of meshes of nets shall be tested, approved, and certified by the department of agriculture, or other governmental entity authorized to so certify, and authorized by the chief of the division of wildlife.
R.C. §1533.52