Selective fishing with the aid of electric nets and LED lights
Various types of fishing gear are utilised, depending on the species or habitat. Bottom-living species are caught using bottom trawls, whereas fish living in open waters are caught using pelagic nets. Steel long-lines – carrying hundreds of thin lines and baited hooks – are often used to catch tuna.
Some of these fishing techniques have considerable disadvantages. A prime example is the beam trawl, a type of net that is dragged across the seabed. Beam trawls are often equipped with iron chains that disturb the flatfish on the seabed and drive them into the net. The beam trawl is the subject of considerable controversy because it ploughs its way along the seabed and destroys numerous bottom-living creatures.
Long-lines, in turn, are notorious for their bycatch harvest of dolphins and turtles, which are attracted by the bait on the hooks. Seabirds such as albatross are also frequent casualties: they dive for the bait when the lines are thrown from the ship into the water and are briefly suspended near the surface. Over recent years, various alternative and gentler fishing techniques have therefore been developed:
- the Danish seine, a specific form of towed net. Conventional trawl nets are generally equipped with weights to help them sink. However, these weights can kill other marine fauna or damage sensitive seabed habitats. With a Danish seine, contact with the seabed is minimized due to its specific geometric structure, consisting of diamond knotted netting turned 90° from its usual orientation;
- pelagic trawl nets with escape hatches for turtles;
- long-lines with additional lead weights that cause the lines to sink rapidly, taking them out of seabirds’ reach;
- unusually shaped hooks for long-lines that avoid turtle bycatch;
- electric fishing nets which produce a mild electric pulse to disturb the flatfish and drive them into the net, instead of using heavy chains (tickler chains) for this purpose;
- gillnets equipped with fishing lights (LED markers or lightsticks), which scare away turtles or alert them to the presence of the net.
- 5.13 > Different fishing techniques and their impacts on the environment
PURSE SEINE NETS
- For some years, the development of gentler (i.e. more selective) fishing technologies has been promoted by an international environmental organization through the Smart Gear initiative. It is noteworthy that it is not only researchers and engineers who are involved in the initiative; so too are professional fishermen. The many different solutions offer hope that gentler forms of fishing will come to the fore. Many fishermen, especially in Northern Europe, have already switched from beam trawling to alternative fishing techniques for pragmatic reasons. With rising oil prices, dragging a heavy beam trawl along the seabed is no longer economically viable. In many areas, lighter fishing gear such as Danish seines is being used instead.
Generally speaking, effort-based management must be constantly adapted to the latest technological advances. Increasingly efficient technology is available to locate fish, for example, making it possible to detect and catch a given amount of fish in ever shorter periods of time. Experts estimate that industrial fishing is achieving a 3 per cent increase in efficiency year on year, so fishing effort must be reduced.
Another way of protecting fish stocks is to establish designated marine protected areas, where fishing is restricted or subject to a total ban. In some areas, bottom trawling, for example, is prohibited altogether in order to protect seabed habitats. In other cases, specific areas are protected, notably those where fish come to spawn and juveniles grow to maturity. This approach can only be successful, however, if very accurate information is available about the whereabouts and reproduction habits of fish or marine fauna in relation to the protected areas. Furthermore, a protected area must be the right size. If it is too small, the stock will not be adequately protected. If it is too large, the fishermen will lose access to stocks that they could in fact catch without putting stocks at risk.
Sustainable, high-yield fishing is possible
Despite the numerous problems, well-organized fisheries management can work, as the examples of Alaska, Australia and New Zealand show. Most stocks in these regions are fished sustainably and are in a good state. In many cases, TACs and ITQs have been set in accordance with the maximum sustainable yield (MSY) principle, i.e. the maximum annual catch that can be taken from a species’ stock over an indefinite period without jeopardizing that stock.
In some fisheries, the limit reference points and target reference points for the maximum annual catch are even more stringent than the MSY. The following factors contribute to successful fisheries management:
- The fishing industry and policy-makers comply with researchers’ recommendations on catch volumes and with limit reference points and target reference points.
- Various interest groups are involved in the management process at an early stage. Researchers’ expertise plays a key role in the setting of quotas. In addition to commercial fishing companies, recreational fishing associations and non-government organizations are involved in the allocation of fishing rights, in measures to avoid bycatch, and in other aspects of fisheries management.
- Responsibilities for the various aspects of fisheries management are clearly defined and hierarchically structured. Fishing in international waters is regulated by one of the Regional Fisheries Management Organizations (RFMOs). Fishing in the exclusive economic zone is managed by national authorities, while fishing in coastal waters falls within the jurisdiction of local authorities.
- Government observers are deployed and their operating costs are covered by the fishery enterprises, generating funds for the research community. The entire Alaska pollock (Theragra chalcogramma) fishery, for example, is monitored by onboard observers. Landings in port are also monitored by CCTV.
- The focus is not only on individual fish species: efforts are also made to manage fishing in a way which protects the ecosystem as a whole. Experts call this the ecosystem approach. Among other things, it means that no heavy fishing gear can be used that would potentially damage the seabed.
- The management authorities are willing to learn from others’ mistakes and, from the outset, target their measures towards avoiding overfishing. This is the case in both Alaska and New Zealand, where industrial fishing began only around 20 years ago.
- In the USA, the Magnuson-Stevens Fishery Conservation and Management Act adopted in 1976 contains the main legal provisions applicable to fishing. The Act has been revised several times over the years, most recently in 2007. The latest amendments introduce measures for the USA as a whole which are very much in line with some of those already in place in Alaska. For example, fishing should now take greater account of environmental conservation aspects and protect important fish habitats. The objectives defined in the Act are to be achieved with the aid of fishery management plans (FMPs) which incorporate the economic, ecological and social dimensions. Although there is some opposition to these stringent rules in the USA, they are now established in law and non-governmental organizations can bring legal actions in the event of violations.
The right management regime for each stock
So which management measures are most appropriate to generate a high but sustainable yield over the long term while protecting fish stocks and marine habitats? This will ultimately depend on the fish stock and the local situation. In industrial fishing, which is carried out using vast vessels and provides employment for around 500,000 fishermen worldwide, the fishing activity could, in theory, be monitored by onboard observers, although this is associated with high costs. However, in countries where artisanal fishing involving hundreds of small boats is the norm, as in West Africa, this type of surveillance measure cannot possibly work. With an estimated 12 million artisanal fishermen worldwide, it is quite impossible to monitor all of them at work. Nonetheless, there are some promising strategies for monitoring the catches of small and medium-sized coastal fisheries as well. In Morocco, for example, the authorities have introduced automated systems to monitor coastal fishing. Machines are installed in port or in the coastal villages and fishermen are allocated a chip card which they insert into the machines to register their departure and arrival times. This gives the authorities an ongoing overview of which particular fishermen are at sea at any given time. If a ship does not return to port on time, the authorities can run preventive checks. This system also allows fishing effort to be estimated very accurately. The catches are recorded by the authorities on landing. At present, the system is used to record vessels of trawler size, but from next year, smaller motor boats will also be monitored using this system, with spot checks on these smaller vessels’ catches also being carried out. Penalties are imposed on fishermen who provide false information about their catch. These penalties depend on the severity of the offence, but in some cases can include the confiscation and scrapping of the boat.
- 5.14 > Fishing without bycatch: stilt fishermen in Sri Lanka’s coastal waters wait patiently for their prey, which they haul out of the water with rods and landing nets.
More regional responsibility
Territorial use rights in fisheries (TURFs) are an alternative to centralized approaches to fisheries management. Here, individual users or specific user groups, such as cooperatives, are allocated a long-term and exclusive right to fish a geographically limited area of the sea. Catches and fishing effort are decided upon by the individual fishermen or user groups.
This self-organization by the private sector can also help to achieve a substantial reduction in government expenditure on regulation and control. Users also have a vested interest in ensuring that they do not overexploit the stocks, as this is necessary to safeguard their own incomes in the long term. However, a use right for a stock of fish or other living resource in the ocean is exclusive only for non-migratory species such as crustaceans and molluscs.
One example of successful management by means of TURFs is the artisanal coastal fishery in Chile, which mainly harvests bottom-living species, particularly sea urchins and oysters. Fishermen here have shown that they have a vested interest in pursuing sustainable fishing once they have the prospect of obtaining secure revenues from these fishing practices over the long term. Similar approaches are being pursued in the lobster fishery
in Canada. Experts use the term “co-management” to describe this trend towards more individual responsibility for fishermen (ownership). >