Quantifying mesh resistance to opening of netting panels: experimental method, regression models, and parameter estimation strategies

The increased mesh resistance to opening of netting panels manufactured with thick and stiff twines has a notable impact in the structural response and selective performance of the fishing gears. The only available method to quantify the mesh resistance to opening of netting panels was described in Sala et al. (in Experimental method for quantifying resistance to the opening of netting panels. ICES Journal of Marine Science, 64: 1573–1578, 2007b). We present an alternative method with a similar methodology: we attempt to estimate the mechanical and geometrical properties of a netting material that best fits the experimental measurements of a netting panel. We introduce three major contributions: (i) a considerably simpler uniaxial experimental set-up, which stretches a netting sample in the normal direction of the meshes while leaving free its deformation in the transverse direction; (ii) more accurate theoretical models for mesh resistance to opening; and (iii) new strategies to estimate the parameters of the models. We present the results of the analysis of polyethylene, compacted polyethylene, single-twine, and double-twine netting. Some of the assessed combinations of estimation strategies and theoretical models have an excellent goodness of fit with experimental data. The method proved to be a simple yet accurate way to quantify the mesh resistance to opening of netting panels.