Constraints on the realization of the potential of culture-based fisheries are presented from a number of viewpoints. The need for stocking is appraised in light of what appears to be a considerable ability for self-replenishment. Indigenous fishes that could effectively contribute to culture-based fisheries are considered. Additionally, the state of exploitation of inland waters is examined in relation to the need for stocking.
Institutional capabilities to provide academic education, applied research results, management, and extension are evaluated. Finally, coordination of development and management is assessed.
The ideal combination of characteristics for candidates for culture-based fisheries is a fish well adapted to natural conditions that fetches a good price and for which the culture technology already is in place and fingerling production is cheap. In Ghanaian inland waters Oreochromis niloticus meets these criteria. The technology to produce Clarias gariepinus fingerlings exists, but is not yet practiced in Ghana. Chrisichthys nigrodigitatus meets all of these criteria for lagoon systems, except for culture technology; however, a simple technology exists in Cote d'Ivoire and it is cheap.
Macrobrachium vollenhoveni is an interesting candidate on which to base high-value culture-based fisheries in reservoirs. It is also a candidate for culture. Development of a M. vollenhoveni CBF could be the basis of an investment project, especially if combined with the development of a hatchery and commercial culture technique. However, before that can be undertaken, information that clearly specifies its conditions for reproduction has to be obtained. Market demand has to be estimated. A simple, cost-effective culture technology has to be developed. Finally, the economic feasibility of prawn CBF and culture has to be established.
Recommendation: The FD should undertake a phased project to assess the potential of Macrobrachium vollenhoveni for CBF and for commercial culture
The project outline arising from this recommendation is in Working Paper No. 13.
Historically, the freshwater clam, Egeria radiata, has provided a geographically limited, but locally important fishery in the lower Volta. Pople (1966) indicates that the Volta clam fishery is probably centuries old. Before the Volta Lake, the annual harvest was put at from 4–7000 t.
Pople (op cit.) mentions several characteristics of the clam and its fishery that could make it the objective of a development project:
In Ghana, fishermen have learned to transplant the young clams laterally and upstream to “farms”. Thus, a tradition for “transplant” fishery exists;
It spawns and develops without the presence of any saltwater;
It will grow when transferred into stagnant water in dams and creeks, but the flesh becomes less palatable and it may not reproduce in such conditions;
The results of a recent study of the Egeria fishery in the Cross River, Nigeria (Moses, 1990), indicate a sustainable meat weight of about 112 kg/ha/y.
Although it is likely that development activities could enhance the existing fishery, a better justification for a project would be if the clam is found to be more widely distributed than in the past and if, in fact, in can be successfully grown outside its present range.
Recommendation: The Fisheries Department should undertake a study of the distribution of the freshwater clam and its fishery in the Lower Volta as a preparatory activity for a project to follow.
The activity outline is in Working Paper No. 13(f).
Lack of suitable species is not a constraint on the development of culture-based fisheries; however, a lack of suitable culture technologies for some species is a temporary impediment.
Hatchery capacity of produce stock for CBF is considered in Section 4.1.2, below.
3.2.1 Lagoons
Based on observations of the mission4 and the literature (Mensah, 1979; Pauly, 1976), lagoons generally are heavily fished. Catches seem small as do the sizes of the individual fish in the catch, a sign of over-exploitation. Therefore, they could be potential targets for CBF. However, a thorough-going survey of the fisheries and environmental conditions is a prerequisite to the design of any stocking programme.
Brush-park fisheries could be a better alternative than CBF in lagoons through providing significant increases in yield based on natural production and by introducing management of the resources by the fishermen themselves. Brush-park fisheries have been successful in Togo, Benin and Cote d'Ivoire. However, there have been political and social difficulties with their introduction and operation. Therefore, careful planning is an essential element of this kind of development.
Recommendation: The Fisheries Department should undertake a lagoon brush-park feasibility study as a pre-investment project activity.
The project outline is given in Working Paper No. 13(g).
Another possibility for lagoon areas is extensive fish and penaeid and brine shrimp farming in saltworks ponds. Advantages are that little or no capital investment is required to modify existing ponds. In the simplest form, extensive culture would be based on species already present.
The project outline is given in Working Paper No13(h).
3.2.2 Reservoirs
Observations of catches at some reservoirs5, data from Fisheries Department reports and interviews with knowledgeable persons indicate that reservoirs are not being too heavily exploited despite relatively high apparent densities of fishermen, low catches per fisherman and some low yields per unit area (Table 4). Ghanaian reservoirs appear to be yielding 25% less than global averages for reservoirs of similar size. Despite this, there appeared to be ample fish in the catches. Many fishes were of a size large enough to have reproduced at least during one breeding season before capture. In several reservoirs quite large individuals were in the catch. There are closed seasons of about 3 months duration during the spawning season on all but two of the reservoirs, Mankessim and Afife; however, the latter is fished only part of the year voluntarily. No data were seen to demonstrate the efficacy of the closed seasons; however, the regional secretary of the fishermen's association in Northern Region volunteered that the fishermen believe that the closed seasons were working.
Fishermen densities on lakes and reservoirs range up to 6 per square kilometre (Kapetsky, 1984). The relatively high fishermen densities on reservoirs in Ghana (Table 4) seem to be due to the part-time nature of fishing by persons who also farm or have other means of earnings. Thus, the reservoirs can accommodate more fishermen than is usual where fishing is full-time.
Table 4. Fishery characteristics of some Ghanaian reservoirs
| Name | Area (ha) | Fishermen | Catch | Notes | ||
| n | n/km2 | t | kg/ha | |||
| Mankessim | 192 | 37 | 19 | - | - | 1 |
| Afife | 720 | 125 | 17 | - | - | 2 |
| Tono | 1860 | 207 | 11 | 102 | 55 | 3 |
| Vea | 380 | 90 | 24 | 4.4 | 12 | 4 |
| Bontanga | 770 | 60 | 8 | 4.8 | 6 | 5 |
| Bunglun | 25 | 10 | 40 | 1.8 | 72 | 6 |
| Libga | 48 | 20 | 42 | 3.4 | 71 | 7 |
| Golinga | 46 | 20 | 44 | - | - | 8 |
1 interview with fisherman
2 interview with IDA manager
3 interview with secretary of fishermen's association; catch fromFisheries Department reports
4 Fisheries Department reports
5 catch from Fisheries Department reports; fishermen numbers fromsecretary of regional fishermen's association
6 data as from Bontanga
7 data as from Bontanga, but catch from unregistered fishermenis not included
8 fishermen numbers from secretary of regional fishermen'sassociation
In fact, some reservoirs are not being exploited at all. These are reservoirs administered by Ghana Water and Sewerage Corporation (GW&S) for urban water supplies. A number of regional directors of GW&S indicated that, although the policy was not to permit uncontrolled fishing because of a fear of damage to the plant due to, say, the use of explosives, they would be willing to permit fishing, if it could be supervised. Not including Weija Reservoir that is already fished, seven reservoirs totaling about 660 ha with a potential yield of about 73 tons at 110 kg/ha, fall into this category. A positive aspect of these reservoirs from the fish marketing viewpoint is that they are relatively close to urban centres.
Recommendation: A Fisheries Department-Ghana Water and Sewerage Cooperation working group should be established to devise fishing development and management plans for the GW&S reservoirs.
Virtually everywhere the mission travelled fishermen and Fisheries Department officers complained of the scarcity and high prices of fishing materials. Fish farmers indicated that meshes needed for seine nets were unavailable, or very costly. The complaints were too numerous to lack substance. Furthermore, Fisheries Department reports show that lack of inputs for fishing has been an almost perennial problem. Materials appropriate for inland fishing are not being imported and distributed in sufficient quantity and the distribution is spotty.
One inland fishermen's association has compiled a list of the kinds and quantities of fishing materials its membership requires. Thus, there is not a lack of comprehensive information on which to act.
Recommendation: Because the lack of appropriate gears appears to be a serious impediment to fishing, the Fisheries Department, in consultation with inland fishermen's associations and taking into account the needs of fish farmers, should estimate the demand for materials for inland fishing by region. This should be communicated to the state trading companies for action and the same information should be published for the awareness of private merchants.
At Tono Reservoir the state of the fishing gear was very poor, undoubtedly contributing to low harvests. Fishermen did not appear to have good net making or repair skills.
Recommendation: The Fisheries Department should investigate the quality of construction and of repair of fishing gears. If poor, net making and repair short courses should be organized. These activities could be incorporated in the CBF project outlined in Working Paper No.13(a).
The mission did not specifically consider lack of processing skills as an impediment to the development of CBF; however, in Northern Ghana where the people do not have a fishing tradition, this could constrain CBF development.
Recommendation: Training in processing along with training in fishing should be considered as an activity in CBF development activities. This could build on earlier training programmes executed by the Fisheries Department.
The report of the economist deals with transport costs in relation to fish farming and CBF (Working Paper No.5). Transport costs have to be taken into consideration in two ways. The Fisheries Department costs are for fingerling transport and for follow-up assessments of stocking results.
Marketing is covered in Field Technical Report 3. Given the expected increase in demand for fish and the present low rate of fish consumption in Northern Ghana where CBF are most likely to be active along with the relatively poor opportunities for fish farming there, lack of markets should not be an impediment to the development of CBF.
