Unit I6 - Fisheries Industry Impacts


Unit I6


While some subsistence fisheries have led to overfishing, most have achieved a balance with the productivity of the local fisheries resources. Subsistence fisheries generally exploited a wide range of edible fish and other animals found on the reef and in coastal waters at levels that were approximately sustainable. In the absence of ways of storing an excess catch, such fishing tried to meet a moderate but constant demand determined by the size of the local population. If the resource was less than the demand for it, limits were usually established either on fishing for, or on consumption of, the resource in question.

Several things have now changed the possibilities for developing fishery resources. Fish can be stored more easily through salting, icing, freezing or canning, so there is a way of using catches that are more than what is needed for local consumption. The development of urban centres and of various kinds of paid employment has created markets for fishermen who want to sell their fish to those who lack the time or the means to fish for themselves. Transportation links with other countries have even made possible the export of some fisheries products. All of these have helped to encourage the creation of commercial fisheries (fishing for money) in many developing countries.

There are many reasons why commercial fisheries projects and the development of a fishing industry can have important impacts on the environment and coastal resources. The following are some of the most important reasons for and kinds of fisheries impacts.


While subsistence fisheries are limited to the immediate needs of a low density local population, commercial fisheries tend to be larger in size, and to supply markets that may be more demanding, or even almost without any limit relative to the size of the resource. The conservation ethic of leaving behind what you do not need immediately does not apply in a commercial fishery. Thus one of the most important controls on traditional fisheries no longer works with commercial fishing; the fisherman tries to catch as much as he can regardless of the effect on the fish population.

Knowledge of the resource

Most tropical coastal fisheries are still poorly understood scientifically. There have not been enough surveys or research to know what yields are possible or how to manage the resources scientifically. Traditional fisheries experience is often the only guide available, but it is not always easily converted to modern fishing methods and changing environmental conditions.

Many commercial fisheries development projects have failed because the resource was not understood or misunderstood. A reef may be swarming with fish, but this does not mean that it can produce so many fish again quickly once those that are present are caught; the standing stock is not the same as the productivity.

Limited species of commercial interest

Tropical coastal waters have many kinds of fish living together, yet only a few of these will have a high market value or be easy to sell. Commercial fisheries prefer to concentrate on those species that sell easily or bring a good price. Heavy fishing for only these species can upset the balance of resources through changes in food chains and population controls. Less desirable species which may be caught by accident are often just wasted, and much of the available productivity of the environment is not utilized. The commercially-useable yield may thus be lower than the subsistence yield.

New technologies

New and more elaborate fishing technologies have been introduced to rural areas, including larger boats, motors, nets, hooks, lines, reels, spear guns, diving gear, etc. Such technologies make it possible to catch more fish, leaving fewer to reproduce and maintain the population. At the same time better boats have improved travel to all possible fishing grounds, spreading the fishing pressure to the whole population. There are now few places so remote that they can continue to serve as population reservoirs from which more heavily fished areas are restocked. The result of both these factors may be to lower the ability of the total fish population to reproduce and replace those fish that are caught. As the pressure increases, the productivity of the fishery will decline.

These new fishing techniques have eliminated one former factor in fisheries conservation, the inability of traditional techniques to catch more than a fraction of the total population. Where a primitive technology in itself made over-fishing difficult, modern techniques have made it much easier, increasing the need for voluntary restrain or other kinds of management controls.

Support facilities

Many fisheries industry development projects involve the construction of fisheries support facilities such as freezers, harbours, and canneries. These facilities can often have severe effects on the environment in the coastal zone. The construction itself may involve dredging and filling, and may interfere with sediment movement and other coastal processes, causing damaging erosion or filling in. Canneries and other processing plants produce large quantities of fish wastes and washing water that can cause serious local pollution. Refueling and other fishing boat operations may lead to spills of fuel and oil, producing chronic pollution in ports and harbours.

Support facilities may also tend to concentrate fishing activity in the area immediately around the facility. No fisherman is going to use more expensive fuel than he needs to. The result is rapid overfishing in the immediate vicinity of the facility, gradually spreading outward as fishermen are obliged to go farther and farther away to find a reasonable catch.

Economic pressures

The fishing industry requires important capital investments, both individually in boats, motors, nets and other gear, and collectively in ports, processing and marketing installations. Such investments are often financed with loans that must be paid off regularly, putting pressure on fishermen to keep fishing in order to maintain a regular income. It is thus no longer possible to adapt fishing pressure to the needs of the resource, which usually needs periods of protection to allow reproduction and replenishment.

The commercial requirements of a modern economy or industry for constant production and the efficient use of investments are thus not particularly compatible with the ecological requirements of a tropical "hunting and gathering" fishery in a natural unmanaged environment. A resource damaged by a cyclone or simply a bad year may need time to recover, but to stop fishing would mean economic bankruptcy. These economic pressures can make good management of coastal fisheries resources much more difficult, and accelerate the damage to resources through over-fishing. Aquaculture, where (just as in farming) there is more control over the level of production, fits better with commercial requirements.

It is already hard for tropical fisheries to compete with the more efficient overseas temperate water fisheries because of the greater distances and small scale of rural fishing industries. The conflict between commercial pressures and tropical coastal resource requirements makes it even harder to achieve economic success.

Conflict with subsistence fishing

Just as cash crops have hurt subsistence agriculture, so can commercial fishing cause a decline in the local subsistence diet. Fishermen will devote their best effort to the commercial fishery, and important food fish will be sold rather than eaten. The family may only get what cannot be marketed.

Commercial and subsistence fishermen will often be trying to catch the same fish. Since the commercial fisherman is generally better equipped and more efficient, he may reduce fish numbers to the point that less efficient local subsistence fishing techniques are no longer able to give adequate catches.

The presence of the commercial fisherman also destroys the conservation interest of the subsistence fisherman in leaving for tomorrow what he does not need today. The traditional approach to managing the resource is subject to a forced change. If over-fishing results, both the commercial and subsistence fisheries will suffer.

Oceanic fisheries

Offshore or deep ocean fisheries, such as those for skipjack and other tunas, are subject to different management requirements which do not need to be discussed here. However they can have an important impact through the construction of supporting facilities in coastal areas (see above), and through the exploitation of coastal resources of bait fish.

If bait fish populations are not properly managed, there can be over-fishing which would affect coastal fisheries food chains and might have an impact on other fish species of economic importance.

There has also been a widespread problem of oceanic fishing boats from other parts of the world taking advantage of the impossibility of policing all remote islands and coastal areas to poach valuable fisheries resources in coastal waters such as giant clams and beche de mer, with serious effects on the resource. The more foreign fishing boats are attracted by a fisheries development project, the greater the risk of such unwanted side effects.

It should be clear from the above that the fishing industry can have two main types of impacts. One involves coastal pollution, construction and other effects common to many industries in the region. The other concerns the management of the fishery resources themselves, and is related both to the ecological limits of the natural ecosystems exploited and to the importance of coastal fisheries resources for local subsistence. Fisheries development projects must be planned with these possible impacts in mind.

Instructions for trainers in the use of this unit

Return to Rural Environmental Management Home Page

Last updated 2 July 2008