As we have seen, fish production in irrigation canals may take two forms: capture fisheries and aquaculture. In the promotion of both these operations there are legal implications which must be carefully considered if the project is to be a success.
A Fishery development in large eutrophic lakes and reservoirs may be problematic and unproductive. Increased eutrophication caused by urban and agricultural development
Physical subdivision into ponds (China)
Swamp potential for chinampa development with associated aquaculture (Mexico, Bangladesh, Burma, Kashmir)
Pens for fish culture in shallow water or often enclose large areas in lakes and reservoirs (Philippines, Indonesia, China)
Floating fish cages variable production based on degree of supplemental feeding and amount of natural food. Site selection often critical(Philippines, China)
Aquatic mactrophytes can be cultivated in irrigation canals eg water hyacionth, water lettuce used as feed for fish (China)
Fences dividing canals; partitioned areas can be stocked with fish (China)
Small dams/impoundments (5 ha) on the farm for small scale irrigation or water can be stocked with fish (Israel, Taiwan, Thailand, Zimbabwe)
Fish in rice/taro/spinach etc (S E Asia)
Irrigation canals within farms may be stocked with fish eg orchards (SE Asia)
Fixed cages in rivers, canals sewers: a high stocking density is often possible (Cambodia, Indonesia)
Road drainage channels have potential as sites for cage culture which may be seasonal (Panama, Bangladesh)
Borrow pits/Mining pools these could be usedasconventional fish ponds or cage culture areas (Malaysia)
Figure 11 A summary of integration of fish production with natural and man-made water resources (Little and Muir, 1987)
A managed fishery involves purchasing or growing seed fish for stocking, provision of staff etc., or at the very least, regulating the fishing effort, a task which also needs staff. These imply annual costs to maintain or police the fishery. This raises the question of ownership of the fishery resources in the irrigation system. Does the bearer of the management/restocking costs own the fish once they have been released into the canals, or are they common property? Who is entitled to fish them? These questions lead to the conclusion that revenue must be provided from the fishery to cover management and running costs. The collection of this revenue could be via licences, taxes etc. This in turn implies government legislation, which should provide adequate legal devices to make the regulations enforceable. There would also be a need to regulate the fishing effort, in order to sustain the level of production from the fishery, without incurring unreasonably high levels of management input.
In an aquaculture system, as the fish are confined by the farmer, the question of ownership is quite clear. However, there are other aspects to be taken into consideration. These mainly revolve around the fact that the farmer is making use of water that is ultimately destined for use in land-based agriculture, and which is often paid for, at least in part, by these users. Intensive use of irrigation water for aquaculture may also be damaging to the subsequent use of that water in agriculture, through environmental effects of the culture operation, e.g. organic enrichment, obstruction of the waterways etc. Thus, a form regulation, such as licensing, should be considered to:
gain revenues from the activities of the aquaculturists, which could be used to augment the revenues obtained from the land-based farmers, and
to regulate the extent of the aquaculture activities, such that they do not conflict overmuch with the agricultural users, or jeopardise their own operations through environmental deterioration.
These points introduce the further question of legal rights of access and use of the waterway itself. This applies to both aquaculture and fishery situations. The majority of irrigation systems are constructed and maintained by the state government which normally place legal constraints on the use of the water in canals. These legal measures can vary greatly in their extent. For example, in the case of cage and pen culture in Canada there are 12 different licences required before a fish pen can be set up, whereas in Thailand all that is required is a nominal licence fee and permission from a fisheries officer (Carruthers and Clarke, 1981). In West Java any prospective farmer must be prepared to maintain irrigation canals and keep them free of debris. He must also keep any nets at least three metres away from any bridge and is forbidden to use canals with a slope less than 2.5%. This is to prevent flooding which has occurred in the past due to the numerous cages which appeared in the drainage canals in urban areas (Costa-Pierce and Effendi, 1988). Permission from the water authorities is required in Egypt before any aquaculture facility can be placed in irrigation canals. The authorities take account of whether the facility is likely to restrict water flow in the canal, or cause siltation or pollution (Nour, pers.comm.).
Most financial constraints to capture fisheries or aquaculture in irrigation systems are products of the market-place, the local socio-economic conditions, the culture system etc, and are totally unrelated to the conditions of the irrigation scheme. The only generally applicable exceptions to this concerns licences, either for fishing or for aquaculture, and levees on the agricultural water-users by the operators of the irrigation scheme.
In the case of fishing licences, the fee charged should be at a level such that fishing is neither discouraged or made so attractive that overfishing results. In fact a licence fee can be a useful means of controlling fishing pressure. The same argument applies to aquaculture operations.
In many irrigation schemes, water users are charged for the water they use, or for the right to use water from the system. If capture fisheries or aquaculture operations are set up in an irrigation system, should not the beneficiaries of these also contribute to the cost of building and maintaining the system in the same way farmers do? In fact, in the case of large-scale developments, it might be possible to consider a reduction in the rates charged to arable farmers, the shortfall made up by charges to fishermen and fish farmers.
In most developing countries irrigation charges are usually set at a nominal fee which seldom covers the actual cost of irrigation. In India the recommended charges are based on the type of crop grown, but are usually equivalent to 4–15% of the gross income from the irrigated land. However, in reality this figure is usually less than 5% of the farmers gross income. In Pakistan and other developing countries the charges are similarly small. However in Europe, Australia and the USA the charges are substantially higher.