The renewed interest in aquaculture in recent years stems mainly from the stagnating growth rate of marine capture fisheries and the growing uncertainties concerning their sustainability. The scarcity of fossil fuels, the most crucial input for marine capture fisheries, and the fast depleting marine fish stocks have also resulted in a marked shift towards aquaculture. However, the growth of aquaculture seems to have caused more problems than it solved. Irrational growth of commercial aquaculture ventures, indifferent to the environmental norms, can open a floodgate of new concerns, as evidenced in the recent Asian prawn culture boom. While the negative environmental impact of the aquaculture boom has already come to a sharp focus, there is a human aspect of the problem in the form of social disruptions which received much less attention. The traditional inland fishers, especially the inhabitants of the local communities surrounding the water bodies who eke out a living from the inland water bodies, are hit hard by the new developments and suffer on many counts. Various developmental activities had already caused the loss or degradation of many ecosystems, taking a heavy toll on their faunistic wealth. Often there were no avenues for alternative employment for the marginal fishers, rendering them vulnerable. Now, they are totally marginalized by the shift in accent towards intensive farming with excessive dependence on monetized inputs.
It is well recognized that the depletion of wild stock of fish and the resultant erosion of traditional inland fisheries are unavoidable to a certain extent owing to the environmental changes already mentioned. It is equally obvious that all inland water resources cannot be preserved for fisheries purposes without neglecting the genuine developmental needs. Moreover, many developing countries need to increase fish production from inland water bodies in order to alleviate the problems of malnutrition and poverty. Obviously, a country must resolve both intersector and intrasector conflicts before it opts for suitable management options in fisheries development. At the present time, there is a growing realization that the enhancement of fisheries in small inland water bodies can emerge as a possible solution to resolve the conflicts by combining environmental concerns with the growing aquaculture ventures.
In the context of this relatively environment-friendly fisheries development of traditional and enhanced fisheries, the small water bodies (SWBs) assume some significance. A variety of natural and man-made water bodies are often described as SWBs, although a precise and universally acceptable definition is yet to be made. Anderson (1987) included the following water bodies under SWBs: small reservoirs and lakes less than 10 km2 in area; small ponds, canals including irrigation canals; small, seasonal, inland floodplains and swamps; and, small rivers and streams less than 100 km in length. He excluded the following: mangroves; large coastal and inland floodplains; coastal lagoons with intensive, well-established fisheries; and, fish ponds specifically constructed for intensive aquaculture.
The small man-made impoundments, created for irrigation, cattle watering, and multiple community use, form the bedrock of this resource and in many countries they are the only inland fishery resource. The SWBs are as nondescript as they are ubiquitous, which makes the attempts to study their fishery potential a difficult task. More often than not, inventories are not available on such water bodies, therefore, their production potential remains unassessed. Any attempt to compile such data can be very tedious, nonetheless, such studies are vital to the national and international efforts to find solutions to the problems related to management of aquatic resources. The atomistic nature of aquaculture units makes the task of data collection more difficult than the preparation of industrial statistics, the latter having more identifiable locations. Some water bodies assume biological significance by being sensitive areas, providing vital links in the life cycle of organisms. Sometimes, these ecosystems provide shelter and grazing grounds for threatened species of fish during some transient phases of their life cycle.
The current interest in SWBs derives mainly from their utilization for fisheries enhancement, which involves guidance on stocking, exploitation and species management in order to obtain optimum yield on a sustainable basis. The present study is an attempt to probe into the national experience in management of small water bodies in a selected few tropical countries with a view to gauging the resource size and assessing the strength, weaknesses and issues involved in their management from a global perspective in order to facilitate bilateral or multilateral interaction among nations displaying similar characteristics.
This report provides an overview of the small water bodies and their fisheries in southern Africa, Asia and Latin America, represented by Zimbabwe, India, Thailand, Sri Lanka, Brazil, Cuba and Mexico. It depends heavily on the secondary data collected from various government agencies of the countries. A main constraint has been the remote and nondescript nature of the resources, the details of which, if available, were scattered among various agencies. Collection of primary data was impossible within the time frame of the study. These constraints resulted in some lack of uniformity in presentation of data on different countries. Since data have been collected from various sources, they lack the desired degree of accuracy. Nevertheless, the major facets of fisheries management in small water bodies in the seven countries have been highlighted. The main emphasis was on the resource size, organization of fisheries, fisheries management and species management, depending on the availability of data and information.
The seven country reports in this study describe, in detail, the size and variety of the resources available, the management practices followed and the current production trends. An attempt has been made to highlight the basic differences between the countries in the comparative account that follows. Some important trends are discernible vis-à-vis the level of national prioritization received by the resource, the amount of infrastructure and technical support from the state, the general organization of fisheries, the species management and the overall productivity. The national policies and legislative support on the introduction of exotic species and the level of efficiency in enforcement of the existing regulations play a key role in the success of yield optimization efforts in the countries. The overall strengths and weaknesses of the countries in managing the SWBs have been brought into focus and the issues involved in the process highlighted. An earnest endeavour has also been made to offer policy prescriptions of operational significance for streamlining the fishery management of small water bodies, particularly the reservoirs and other man-made impoundments which have promising fishery potential.