trawlers fuck up the sea bed

In this case it was scallop dredgers. And to simply say they fuck up the seabed is an overly simplistic interpretation of a complex interaction. Really there's much more to consider. In highly dynamic inshore environments it's possible that natural disturbance from winter storms can cause comparable damage to certain levels of towed fishing gear pressure (see this research 1, 2, 3). In other more stable and delicate environments, such as within sea lochs, then towed fishing gear can cause huge amounts of long term damage. It is our responsibility to identify where and to what level the natural environment can with stand such impacts and to manage our activity accordingly. It's also our responsibility to harvest our fish stocks sustainably and to make proper effective use of them- not to leave our own resources underutilised whilst importing fish from developing countries where fisheries management and environmental regulation is weaker, thereby increasing pressures on their environment. It's not an easy problem to solve, and anyone who thinks it is solved simply by banning things needs to study the situation more closely.