Influence of a roller clump on the seabed

The effect of the impact of trawl gears on benthic communities has been of concern during the last couple of decades. Knowledge of the response of benthic habitats to impacts from fishing gear is of great importance to the ecosystem and the management of sustainable fisheries. A European project, DEGREE (DEvelopment of Fishing Gears with Reduced Effects on the Environment), addresses this concern by focusing on quantifying the environmental and ecological impacts of fishing, developing fishing gears with reduced environmental impact, and assessing the socio-economic consequences of these changes. This paper is a preliminary study focusing primarily on the comparison between laboratory and finite element (FE) modelling of the interaction between a gear component, the roller clump of a twin trawl, and the seabed in terms of penetration and disturbance of the sediment. The FE model and experimental rig are described. Initial outputs of penetration depth from the FE calculations show that the model is highly sensitive to the yield stress and that further investigation is required to achieve full parity with laboratory observations on dry sand.