Net depth response of a depth-controllable (towed) gillnet for fish sampling
Flume-tank experiments were performed to examine the depth response of a new type of depth-controlled gillnet. Variations of net depth were investigated as the warp was paid out and wound up for different changes of warp length, main sinker weights, and winch speeds. In most experiments, when the warp finished paying out, the net continued to descend and then ascended slightly to an equilibrium depth (overshoot phenomenon). The overshoot distance was nearly constant when the warp was wound up and increased linearly with increasing winch speed when the warp was paid out. An increase in winch speed reduced net settling time, which converged on a constant value for both paying out and winding up.
Document Type: Research Article
Affiliations: 1: Graduate School of Fisheries, Laboratory of Marine Environment and Resource Sensing, Hokkaido University, Hakodate, Hokkaido 041-8611 and 2: Department of Marine Science and Technology, Tokyo University of Fisheries, Minato, Tokyo 108-8477, Japan
Publication date: 2001-02-01