The deepwater fish of the Atlantic Frontier region to the west of the British Isles have long been insulated from any significant human impacts, but fisheries which have developed on these species in recent years have changed this situation rapidly. The impacts from fishing on these deep-sea populations may effectively be irreversible.

Scientific knowledge of the biology these deepwater fish species is limited. As a result, stock depletion of deepwater fish can take place long before scientific knowledge is available - or in some cases before it becomes commercially accessible. However, there is ample evidence which show that these species are very distinct and biologically different from traditional commercial fish, such as the North Sea cod, and should not be treated as the same.

Whilst the deep sea environment is thought to conceivably house the greatest number of species found on the earth, most of them are poorly represented, rare, or are often very thinly distributed. The deepwater fish being caught to the west of the British Isles are largely made up of ‘ancient deepwater species’ which have adapted to life at great depth over a long time period. These species are often long-lived and their annual recruitment is often only a fraction of that of traditional shallow water fish. Therefore any removal by a fishery will obviously take a long time replace, if at all.

Perhaps the best historical example of the development of any deepwater fishery is that of the orange roughy in both New Zealand and Australia in the 1980s. Failure to take the biology of this highly vulnerable species into account, led to populations being depleted to a tenth of their original size.

The orange roughy are thought to live to over 100 years old and only become sexually mature. Studies in Australia have suggested that orange roughy do not spawn when food availablity is reduced, instead conserving energy for their own survival. There are few commercially exploited species, even amongst the great whales which were once heavy exploited, with natural mortality as low as the orange roughy. In the Atlantic Frontier, an orange roughy fishery developed in the early 1990s without any regulations or controls in place. Within a few years the fishery was thought to have ‘commercially collapsed’.

Other deepwater fisheries have developed in the Atlantic Frontier. Some trawl fisheries lead to high levels of discards of non-commercial species. The Ministry of Fisheries and Food (MAFF) have in the past referred to them as ‘trash’ species. They are largely made up of unpalatable species, or species which are considered by the fishing industry as being too small or too rare, or both, to be worth processing. Almost 60 per cent of the catch from depths of 1,000-1,250 metres consists of the ‘smoothhead’ which is discarded because of its watery flesh.

The fragile bodies of deepwater fish can lead to high death rates of young fish when trawled. These can be ‘invisibly’ discarded through the net - that is, fish enter the mouth of the trawl and subsequently escape through the meshes, but are damaged and die later.

Deepwater longlining in the Atlantic Frontier leads to a high mortality of deepwater sharks, which are well known to be very vulnerable to effects of exploitation. Many of the smaller deepwater sharks are discarded, often unrecorded, sometimes after removing their liver which is used in the cosmetic industry.

Fishermen are attempting to treat deepwater fisheries as just another fishery and trying to build up a track-record of catches on these species. In recent years, fisheries managers have attempted to find a scheme of managing these fisheries, but in the end they have been left them completely unregulated. Managers and politicians are currently turning a blind-eye to these fisheries, possibly perhaps with the view that they are a welcome outlet for excess fishing capacity in the shallower water fisheries.

As a consequence, it appears that regulation of these deepwater fisheries will be only be achieved through environmental policy in order that the biological diversity of these remarkable, enduring and well-adapted deepwater species and assemblages will be protected. In the absence of the European Commission adopting such measures, Greenpeace advocates that the UK Government should take unilateral measures to close these deepwater fisheries within the Atlantic Frontier, within their own Exclusive Economic Zone (EEZ). This could be effectively implemented and rigorously enforced by the introduction of restrictions on fishing gear to limit the depth at which a vessel can fish.