A purse seine is made of a long wall of netting framed with floatline and leadline (usually, of equal or longer length than the former) and having purse rings hanging from the lower edge of the gear, through which runs a purse line made from steel wire or rope which allow the pursing of the net. For most of the situation, it is the most efficient gear for catching large and small pelagic species that is shoaling.
Because of its characteristics there is no impact on the bottom habitat (except when the water depth is less than the height of the seine during the fishing operations and that the lower edge of the gear wipes the sea bottom).
The main negative impact is the bycatch of marine mammals and sharks or other endangered species. The increasingly used practice of encircling floating objects, including man-made FADs increases the capture of small sized and immature aggregating around such devices.