Showing papers by "Christophe Béné published in 2003"

Inland Fisheries, Poverty, and Rural Livelihoods in the Lake Chad Basin

Abstract: The objective of this paper is to describe the livelihoods of the rural populations of the Lake Chad Basin area (Sub-Saharan Africa), and in particular to assess the role of inland fishing activity...

Biological Evaluation of Marine ­Protected Area: Evidence of Crowding Effect on a Protected Population of Queen Conch in the Caribbean

Abstract: This study provides a first evaluation of the biological impact of a marine fishery reserve on the stock of queen conch (Strombus gigas) in the Turks and Caicos Islands. The density and the shell length of the population living in the reserve are compared with those of the individuals living in the surrounding fished areas. The results show that the adult density is six times higher in the reserve than in the fished areas. The shell length analysis shows that both adults and juveniles are significantly smaller in the reserve than in the fished area. This unexpected result suggests the existence of a crowding effect (i. e. a high density-induced reduction in growth rate) within the ­reserve. It is hypothesised that this crowding effect is due to the superimposition of two factors leading to very high density values in the reserve: (a) the reduced fishing mortality following the creation of the reserve, (b) the existence of natural barriers that impede the emigration of adults outside the reserve. These results are then discussed in relation to current considerations on marine fisheries reserves.

Natural‐resource institutions and property rights in inland African fisheries: The case of the Lake Chad Basin region

Abstract: Although there exists a rich literature on fisheries traditional management systems in North and South America, Caribbean, Asia and Pacific islands, much less information is available on inland African fisheries. Presents the first regional‐scale survey of traditional management systems operated within the Lake Chad Basin. The survey focused on the status and organization of the local (de facto) management systems and their interactions with the modern (de jure) regulations. The results show that fishing activities within the whole Basin are still largely under the control of the traditional local authorities. The few open‐access fishing grounds are areas that traditional authorities have never controlled or water‐bodies that they have had to “give up” in recent times due to the presence of armed groups. These areas are also areas where illegal taxation systems operated by non‐legitimated governement agents have developed, essentially as a consequence of the remoteness and political instability of the whole Basin.

Effects of natural barriers on the spillover of a marine mollusc: implications for fisheries reserves

Abstract: 1. The movement of organisms and dispersal of propagules is fundamental to the maintenance of populations over time. However, the existence of barriers, created through the spatial configuration of habitats, may significantly affect dispersal patterns and thus influence community dynamics and resource sustainability. 2. Within marine environments unstructured or open habitats may form partial or complete ecological barriers due to elevated risk of predation or physical stresses associated with them. The existence and effects of such barriers may be of particular importance when considering the establishment of marine protected areas with a fisheries enhancement focus. 3. In this paper, the spillover of post-settlement queen conch (Strombus gigas) from a protected area in the Turks and Caicos Islands is investigated. It is hypothesized that the reserve boundaries overlap with a series of shallow, sand habitats that effectively enclose the protected population, reducing the spillover of conch into the adjacent fished areas. 4. To test this, density gradient maps for juvenile and adult conch populations were constructed using underwater visual survey data at 68 sites within and surrounding the protected area. These maps illustrate very low densities coinciding with poor, shallow sand habitats along the two marine boundaries of the reserve where spillover is expected to take place. 5. These sand habitats are thought to create ecological barriers to a slow, sedentary gastropod largely due to their shallowness (physical stresses of solar exposure or anoxia) and lack of food reducing the tendency of individuals to move across these areas, despite the 10-times higher density of adult queen conch observed in the protected area compared with outside. Copyright © 2003 John Wiley & Sons, Ltd.

Fisheries development issues and their impacts on the livelihoods of fishing communities in West-Africa: An overview

Abstract: Fisheries (in particular small-scale fisheries) provide a vital source of food, employment, and economic well-being for rural people throughout the world. In West Africa several million households along the coast and also inland are critically dependent on fishing for their livelihoods. However, fishing communities are often characterised as being amongst “the poorest of the poor”. The main objective of this paper is to review the major issues relating to the development and management of smallscale fisheries in West Africa and to examine their impacts on the livelihoods of the fisheries-dependent communities of the region. Several major issues are identified, discussed and briefly illustrated using numerical examples or extracts of official documents. Globally, it appears that the fisheries sector, despite its potential role as a powerful lever for poverty reduction, is often neglected by national or supra-national decision-makers. Since 1999, however, a number of international initiatives (sponsored by Donor Agencies) have attempted to overturn this negative perception.

Sustainability of fisheries through marine reserves: a robust modeling analysis

Abstract: Among the many factors that contribute to overexploitation of marine fisheries, the role played by uncertainty is important. This uncertainty includes both the scientific uncertainties related to the resource dynamics or assessments and the uncontrollability of catches. Some recent works advocate for the use of marine reserves as a central element of future stock management. In the present paper, we study the influence of protected areas upon fisheries sustainability through a simple dynamic model integrating non-stochastic harvesting uncertainty and a constraint of safe minimum biomass level. Using the mathematical concept of invariance kernel in a robust and worst-case context, we examine through a formal modeling analysis how marine reserves might guarantee viable fisheries. We also show how sustainability requirement is not necessarily conflicting with optimization of catches. Numerical simulations are provided to illustrate the main findings. (C) 2003 Elsevier Ltd. All rights reserved.