| 摘要 |
A fish grading device (1) is formed from an array of generally rectangular apertures (2), each of which is formed by two long tubes (3) and two short tubes (4) of plastics material mounted to a loop of fishing net (5). Each loop of fishing net (5) is formed by crimping the ends of the loop by means of a metal crimp (6). Each of the tubes (3, 4) can rotate freely about its longitudinal axis, so that a fish brushing against a tube (3, 4) will cause the tube to rotate, and will therefore avoid becoming snagged on the tube. When such a fish grading device (1) is included in a fishing net and the net is dragged through the water, small fish are able to swim through the rectangular apertures (2), whereas larger fish are not. Thus only fish of a desired minimum size are caught. |
