Shark and Marine Conservation   Deep concerns Longlining Trawling Coral reefs Marine pollution     Trawling There are many different variations on trawling techniques and the type of equipment used but as fish stocks continue to decline, fishermen have developed more sophisticated gear that now threatens the very structure of the ocean floor whilst indiscriminately catching everything in its wake. The most common technique used today is the 'otter' trawl. It encompasses steel doors designed to drag along the seafloor, keeping the mouth of the net open. Each door is attached to the fishing boat by long bridles. The spread between trawl doors can extend to 650 feet. To keep the base of the net on the seabed the footrope is often fixed with heavy, destructive rolling disks and metal or rubber bobbins that enable the gear to bounce over the seafloor. An average flatfish bottom trawl vessel can catch approximately 15 tons of fish in a single haul. Trawling is an indiscriminate and destructive practice The mouth of a trawl net can extend 650ft Average catch size is approx. 15 tons per haul Trawling has devastated an undersea area the size of Europe To access previously difficult habits trawlers now utilise rock-hopper gear to keep the nets from snagging on boulder fields, deep sea coral reefs and rocky pinnacles. Painfully simple, the rock-hopper gear consists of taut steel chains, the length of the trawl net, punctuated by aircraft tyres that 'bounce' over the terrain. With a combined weight of several hundred pounds, rock-hoppers leave a devastating trail carved into the ocean floor, an area now reported to be twice the size of Europe, removing habitats that have been breeding grounds and refuges for up to 10,000 years.