A DIRECT ESTIMATE OF GILLNET SELECTIVITY FOR BROWN TROUT

Five hundred pre-measured brown trout (Salmo trutta), 20 of each cm-cl ass from 5 to 29 inclusive, were released. They were recaptured with g illnets of mesh size 8.0, 10.5, 16.0, 19.5 and 24.0 mm, measured betwe en adjacent knots. The nets were made of clear, nylon monofilament. Th e modal lengths and the general shape of the selectivity curves were i n agreement with earlier findings. The height of the selectivity curve (S) increased exponentially with mesh size in mm (M): S = 0.047e0.075 M.