Deep sea: threats (www.panda.org) A number of human activities threaten the deep sea:  Destructive fishing practices: Bottom trawling is currently the greatest threat to deep-sea biodiversity. First introduced in the 1980s, rockhopper trawls fitted with large rubber tires or rollers allow bottom trawling on virtually all of the ocean floor down to a depth of 2,000m. These trawls - whose use is now widespread - crush everything in their path. In an experiment off Alaska, 55% of cold-water coral damaged by one pass of a trawl had not recovered a year later. Scars up to 4km long have been found in the reefs of the north-east Atlantic Ocean. And in heavily fished areas around coral seamounts off southern Australia, 90% of the surfaces where coral used to grow are now bare rock. These and other deep-sea trawlers also kill a large amount of unwanted deep-sea life as bycatch. Many fishing practices are extremely destructive to delicate habitats - particularly vital fish breeding grounds like coral reefs and seagrass meadows. For example:  Bottom trawling: Industrial trawlers once avoided coral reefs and other rocky regions of the ocean floor because their nets would snag and tear. But the introduction of rockhopper trawls in the 1980s changed this. These trawls are fitted with large rubber tires or rollers that allow the net to pass easily over any rough surface. The largest, with heavy rollers over 75cm in diameter, are very powerful, capable of moving boulders weighing 25 tonnes. Now, most of the ocean floor can be trawled down to a depth of 2,000m. These trawls - whose use is now widespread - are extremely damaging. In an experiment off Alaska, 55% of cold-water coral damaged by one pass of a trawl had not recovered a year later. Scars up to 4km long have been found in the reefs of the north-east Atlantic Ocean. And in heavily fished areas around coral seamounts off southern Australia, 90% of the surfaces where coral used to grow are now bare rock. When covered with marine life, these seabed areas provide habitat for juvenile fish and other species. Like removing forest, removing this cover decreases the area available for marine species to live and thrive in.  Cyanide fishing: In this technique, fishers squirt sodium cyanide into the water to stun fish without killing them, making them easy to catch. Cyanide fishing on coral reefs began in the 1960s to supply the international aquarium trade. But since the early 1980s, a much bigger, more profitable business has emerged: supplying live reef fish for the restaurants of Hong Kong, Singapore, and, increasingly, mainland China. Some 20,000 tonnes of live fish are eaten annually in the restaurants of Hong Kong - and for every live fish caught using cyanide, a square metre of their coral reef home is killed. Dynamite fishing: In this technique, dynamite or other explosives are set off under water. The dead fish floating to the surface are then simply scooped up. The explosives completely destroy the underwater environment, leaving it as rubble. Dynamite fishing has contributed to massive destruction of, for example, Southeast Asian coral reefs over the past 20 years.  Ghost fishing: Ghost fishing occurs when fishing gear is lost or abandoned at sea. The gear can continue to catch fish, dolphins, whales, turtles, and other creatures as it drifts through the water and after it becomes snagged on the seabed. When driftnets were used on the High Seas, an estimated 1,000km of ghost nets were released each year into the North Pacific Ocean alone. Although the current contribution of ghost fishing to bycatch is unknown, it is likely to have a large impact. One survey estimated that a quarter of the rubbish on the bottom of the North Sea is fishing nets, while fishers speak of a dolphin and turtle graveyard among the nets that drape the cliffs of Cape Wessell, Northern Australia.  Overfishing: Deep-sea species are generally extremely slow growing and do not reach sexual maturity for many years. Some commercial deep-sea fish also congregate in large numbers around seamounts to feed and spawn. And many deep-sea fisheries are located on the High Seas where there is often little or no regulation. These factors make deep-sea fish extremely vulnerable to overfishing. Newly fished populations of deep-sea species like Patagonian toothfish and orange roughy, for example, have been fished to commercial extinction in just a few years. At present most deep-water species are likely to be over-exploited - and as many as 40% of the world’s fishing grounds are now in waters deeper than 200m. The global fishing fleet is currently 2.5x larger than what the oceans can sustainably support1 - meaning that humans are taking far more fish out of the ocean than can be replaced by those remaining. As a result:  52% of the world’s fisheries are fully exploited, and 24% are overexploited, depleted, or recovering from depletion2  Seven of the top ten marine fisheries, accounting for about 30% of all capture fisheries production, are fully exploited or overexploited  As many as 90% of all the ocean’s large fish have been fished out3  Several important commercial fish populations have declined to the point where their survival is threatened  Unless the current situation improves, stocks of all species currently fished for food are predicted to collapse by 20484. Why is this happening? Many fishers are well aware of the need to safeguard fish populations and the marine environment. However, the greed and waste of some large commercial fleets combined with modern developments in fishing technology have had an enormous effect on fishing worldwide. Contributing factors to the current level of overfishing include:  Technological advances that have made large-scale fishing easier  Subsidies that keep too many boats on the water  Unfair Fisheries Partnership Agreements that allow foreign fleets to overfish in the waters of developing countries  Pirate fishers that don’t respect fishing laws or agreements  Massive bycatch of juvenile fish and other marine species  Destructive fishing practices  A lack of sound fisheries conservation and management  Oil, gas, and mineral exploration: At present, most oceanic reserves of oil, gas, and minerals are extracted from the continental shelf, under shallow coastal waters. However, with valuable reserves also located under the deep ocean floor, the oil and mining industries are expected to venture further afield, and eventually explore down to 3,000m. Such activity could have devastating effects on fragile, slow growing deep-sea communities. The extraction of oil, gas, and minerals from the Earth's crust currently provides most of the energy and resources needed to run our society. And to meet our ever-increasing energy demands, the extractive industries are increasingly moving into new areas - including remote areas with fragile ecosystems and unique biodiversity, where governments often have limited capacity to protect the environment or the people who live there. Valuable areas under threat. In many cases, oil and gas exploration and drilling is permitted in or near Marine Protected Areas (MPAs). WWF believes that the threat posed by oil developments - and the oil and gas industry's track record in often failing to protect the environment adequately - makes such developments too big a risk to be allowed near or in MPAs. However, even if exploration and drilling were prohibited in and around all marine parks and reserves, many areas of high conservation value would still be vulnerable - less than 1% of the world’s oceans has been declared as MPAs. Lack of planning and control. At present, environmental concerns are not always routinely considered in plans for offshore oil and gas exploration and development. Environmental impacts are often inadequately assessed, and the assumption is usually that developments will go ahead in all areas, regardless of their ecological value. In addition, many companies operate to different environmental and social standards depending upon the county in which they are working. In some developing countries, this means that even the most basic environmental requirements are not followed. Another problem is that decommissioning of infrastructure is rarely considered. Many exploration wells will only have a limited life, sometimes as little as one to three months, but their construction can have a long- lasting impact. Environmental disruption would be reduced if planning for decommissioning was considered during the design process.