Response Prediction and Monitoring Feasibility of a Stow Net System Using Measured Environmental Data in the Southwest Coast of Korea

Chungkuk Jin,Moo-Hyun Kim,Junho Choi

doi:10.3390/app8091517

Abstract

This paper investigates the response characteristics of a stow net under wave and current excitations, as well as the feasibility of its monitoring system to check net functionality and prevent loss of fishing gears. The stow-net model is based on one of existing types used in southwest coast of South Korea. The measured wave and current data there are acquired and inputted as environmental loads for numerical simulations. The Morison equation for a moving object with equivalent net model is utilized as the external-force estimator, which has been validated by many researchers regarding fish-cage studies. Since the modelling of all the net elements is inefficient in terms of computational time in time-domain simulations, cruder equivalent-drag net elements are devised with equivalent wet mass, projected area, and axial stiffness. The performance of stow net is highly influenced by current velocity. Stow nets submerge more in stronger currents, which results in less wave forces. The proposed monitoring system can provide useful information, such as net functionality and loss of stow net, using the minimum number of monitoring sensors.

Highlights

Marine-environmental pollution caused by marine litter has increased
The stow net freely changes its direction according to the direction of current flow by a single-point-mooring line (SPM) fixed with anchor, and the current force leads to the catch of fish
As a qualitative comparison, the general trends in the present numerical simulations coincide with the experimental results

Summary

Introduction

Marine-environmental pollution caused by marine litter has increased. The marine-environmental pollution caused by the loss of fishing gear is recognized as a serious problem [1]. In South Korea, 20% of used fishing gears are lost or abandoned, and only approximately. 15% of the lost or abandoned fishing gears are collected—the remaining 85% may harm the marine ecosystem [2]. The predominant type of fishing gear in South Korea is the drift gill net, stow net, and fish trap. The stow net has traditionally been utilized on the southwest coast of South Korea by using strong tidal current [3,4]. As the stow net influenced by strong current and wave excitations, the possibility of net-loss increases a lot through braking of lines or twisting of net assembly

Objectives

Results

Conclusion