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Trawling can destroy important seagrass beds
Trawling can destroy important seagrass beds
Courtesy of NOAA/OSDIA/Richard B. Mieremet

Issue

All fishing methods have an impact on the target resource and may affect also non-target species and the wider aquatic environment. But the "normal" effect of exploitation should be compatible with sustainable use and reversible. It should not be confused with "destruction" which, according to the dictionary implies "to reduce to a useless form, to spoil completely; to put out of existence; to obliterate, wipe out, annihilate, demolish, devastate, tear down, raze".

The term "destructive fishing" has, however, often been used for a wide range of situations spanning from classical overfishing (non sustainable use) to outright destruction of the resource and its environment, as for example when using explosives or other methods with significant and definitive impact. Indeed, many fishing gears could be considered "destructive" if used in the wrong environment. In a fisheries management perspective, it is important to distinguish among:

  • reversible overuse or overfishing, to be corrected mainly through input/output controls and proper incentives;
    low-selectivity, which in most cases can be corrected through improved gear technology, closed seasons or closed areas, etc.; 
  • destructive fishing practice, or destructive use, e.g. when a gear is used in the wrong habitat, such as bottom trawls in seagrass, macro algae or coral beds, where the gear should be prohibited or used at a rate that would only affect a relatively small part of the given habitat; and
  • destructive methods, the impact of which are so indiscriminate and/or irreversible that they are universally considered "destructive" in whatever circumstances and should be systematically banned.

The use of poisons and explosives are prominently cited in literature, together with the muroami fishing, as examples of destructive practices. The economic losses for the local and wider society resulting from such damage far outweigh the short-term individual gains made by the users of these destructive methods.

Poisons The use of poisons is widespread, in some regions in both fresh and marine waters -- especially in coral reefs and coastal lagoon fisheries. In many places the use of poison is a traditional practice but the effects have been exacerbated by the use of pesticides to replace poisons of vegetable origin. As fish become scarcer through overfishing or in order to catch rare, small and precious aquarium fish, local fishers often resort to using poisons such as cyanide or pesticides. Fishers can easily obtain inexpensive cyanide used in the jewellery industry and gold mining. Pesticides are readily available to farmers, which are often also part-time fishers. Techniques used vary across regions/localities. They are effective at killing or stunning, indiscriminately, the fish, which are then collected by divers, or through netting and seining. The poisons kill also other organisms from the ecosystem, including the coral reef-building organisms.

Explosives Fishing with explosives, also known as blast fishing, has probably been in existence for centuries and is apparently spreading. Explosions can produce fairly large craters, devastating 10-20 square meters of bottom. In coral reefs, recolonization of damaged habitats is very slow and complete recovery may take several decades. The explosion kills both the target fish and the accompanying fauna being indiscriminate in size or species. In many instances, errors of manipulation have lead to injuries and death of humans. Explosives and the raw materials for preparing explosives such as fertilizers and sugar are inexpensive and easily available. Commercial explosives are often obtained from mining or construction activities. In many areas, fishers only need to extract the explosive charges from munitions left from armed conflicts. In other areas, fishers can access army munitions through illegal channels. Explosives can have very serious consequences for the resources, the environment and, unfortunately, sometimes also for the users themselves.

Muroami The muroami fishing technique, employed on coral reefs in Southeast Asia, uses an encircling net together with pounding devices. These devices usually comprise large stones fitted on ropes that are pounded onto the coral reefs. They can also consist of large heavy blocks of cement that are suspended above the sea by a crane fitted to the vessel. The pounding devices are repeatedly and violently lowered into the area encircled by the net, literally smashing the coral in that area into small fragments in order to scare the fish out of their coral refuges. The "crushing" effect of the pounding process on the coral heads has been described as having long lasting and practically totally destructive effects.

Inadequate practices Some standard fishing gears could be used in a way, which damages the resource and/or the environment, to such an extent that they could be (and have been) considered as "destructive" fishing practices. These may include, inter alia, the following practices that can be properly regulated and controlled:
•    beach seining, because of the large proportion of juveniles yielded and often discarded;
•    bottom trawling (including dredgers and scrapers) because of its impact on the bottom and on bottom-dwelling animals and benthos such as sea stars, urchins, clams, etc. In addition, when improperly used in the wrong environment e.g. on coral reef areas or coastal seagrass beds (despite of being generally prohibited in such areas) it may have very long lasting negative effects on the habitat; and,
•    large-scale pelagic driftnets because of their ability to snare large marine animals such as mammals, sharks, turtles and a number of vulnerable species.

Dolphins are among the large marine mammals caught in driftnets
Dolphins are among the large marine mammals caught in driftnets
Courtesy of OAR/National Undersea Research Programme/M.Herko

Possible solutions

The techniques universally recognized as "destructive" can only be explicitly banned and their use severely punished. Most inappropriate ways of using fishing gear have been identified and are prohibited in national legislation. However, experience shows that this is not sufficient because in stressing economic situations, the incentives to misbehave might be very high. For the poor, poisons and explosives are among the most inexpensive methods available, requiring little capital investment. In some instances, it is the only affordable access to a vital resource. Often, however, the replacement of poison and explosives by other types of fishing methods is within the financial means and reach of those who currently use destructive fishing practices.

For the poorest, however, it will be difficult to suppress bad fishing habits without improving their economic condition. In these instances, the long-term solution to the use of destructive methods is in improving livelihoods or providing affordable alternatives. The muroami technique does not seem to be associated specifically with poverty. It often reflects a total disregard for sustainability and as such should be banned.

The destructive modes of use of other more standard gears can also be "promoted" by chronic overfishing, in a very damaging vicious circle. Proper practices should be regulated through protection of particularly important areas or habitats (seagrass and macro algae beds, coral reefs), as well as closed seasons (particularly to protect juveniles or sensitive species).

Eliminating destructive methods requires finding solutions to a number of issues affecting the fisheries sector such as overfishing (an example of "the hen and the egg" dilemma), inequitable resource allocations, food insecurity and poverty. In most cases, there is a need to improve stewardship over the resources through better monitoring and control, educating fishers about the destructive nature of their practices, and the establishment of explicit forms of use rights for local communities together with decentralised management responsibilities as well as no-take areas. There is evidence that the allocation of use rights will create a strong incentive for communities to use responsible fishing practices and persecute and punish trespassers.

Action taken

Awareness about these methods and their effect is growing. All national fishery laws generally prohibit poisons and explosives but enforcement is often inadequate. Large-scale pelagic driftnets have been banned by the United Nations General Assembly. The use of beach seines is prohibited in many countries and areas. The coastal areas with coral reefs or coastal seagrass beds are usually prohibited to trawls. However, the realization of the existence of cold water corals in large parts of the deeper continental shelf and slope areas poses additional management challenges. It should be recognized that enforcement is often difficult, particularly in the case of offshore fisheries.

Programmes have been implemented to educate small-scale fishing communities of the damage caused by explosives and cyanides. On the technical side, many programmes worldwide have been initiated in order to develop trawls and trawling techniques with reduced bottom impact. Furthermore, area closures are introduced to prevent the use of bottom trawls on sensitive habitats. The devolution of fishing rights and responsibilities to coastal communities (e.g. in Philippines) and their greater involvement with other stakeholders and NGOs in the management of resources accompanied by programmes to raise awareness of the long-term damage of such fishing techniques have contributed to the promotion of local social pressure and enforcement to control destructive fishing. In addition, the development of tourism can increase the value of the fish and the environment creating incentives for their better conservation, provided the economic benefits of development are equitably distributed.

Outlook

More of the actions mentioned above are still needed to reduce destructive fishing. These include measures aimed at suppressing overfishing, improving livelihoods, and reducing poverty that all contribute to reducing the probability of and need for using these methods. The evolution of the problem in the future largely depends on local conditions and it is difficult to generalize. At the moment, and with the little information available, the problem seems to be spreading. Once described mainly in Asia and Africa, it is now becoming more widespread in the Mediterranean and Latin America. It is unlikely to regress without the greater establishment of explicit use rights in fisheries. Moreover, the complete cessation of such destructive practices is likely to require that the economic situation of the poorest strata of the fishery and rural sectors improves significantly. 

 
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