We compared the effects of water resource development on migratory fish in two North American rivers using a descriptive approach based on four highlevel indicators: (1) trends in abundance of Pacific salmon, (2) reliance on artificial production to maintain fisheries, (3) proportion of adult salmon that are wild- versus hatchery-origin, and (4) number of salmon populations needing federal protection to avoid extinction.
In the absence of reliable data on the species composition of the catch in the Lower Mekong Basin, the authors look at three approaches to estimate the size of the region’s migratory fish resources.The article, based on three different studies, concludes that 700,000 tonnes to 1.6 million tonnes of migratory fish are at risk. These possible losses correspond to respectively five times the size of the fishery sector in Finland and the whole fishery sector in Denmark.
The past decade has seen increased international recognition of the importance of the services provided by natural ecosystems. It is unclear however whether such international awareness will lead to improved environmental management in many regions. We explore this issue by examining the specific case of fish migration and dams on the Mekong river. We determine that dams on the Mekong mainstem and major tributaries will have a major impact on the basin’s fisheries and the people who depend upon them for food and income.
The Basin Focal Project for the Volta (BFP-Volta) is a research project funded by the Challenge Programme on Water and Food (CPWF). Its aim is to provide an in-depth analysis of the basin through three main thematic issues: water-poverty, water availability/use and water productivity. The overall objective of the BFP-Volta is to contribute to the main goal of the CPWF, that is, to alleviate poverty through better management of water in order to enhance agricultural productivity and environment conservation.
This paper draws on approaches in ecology, biology and policy analysis to examine the tensions between dams and fisheries in the Lower Mekong Basin. We review the exceptional importance of Mekong fisheries in terms of total catch, economic value and their role in rural livelihoods. The ecological conditions necessary to sustain the fish production are also analysed. The paper then considers the implications of dam development in the Mekong Basin, drawing on recent research to review predicted changes in hydrology and the resulting impacts on fishery resources.
In this paper, we assess how resettlement and changes in water access have altered livelihoods of local communities upstream of the Theun Hinboun Expansion Project in Lao PDR. Based on household surveys conducted both before and after resettlement, we estimate changes in water use and benefits among households of 4 resettled villages.
The Mekong is an exceptional river in many ways. In terms of fish biodiversity, it is the world’s second richest river after the Amazon (www.fishbase. org). With 6 to 18% of the global freshwater fish catch, it is also home to the largest freshwater fisheries in the world. The productive Mekong fisheries are essential to the food security of the 60 million people of the Lower Mekong Basin. Fish contributes 81% of the population’s protein intake in Cambodia and 48% in Laos. Mekong inland fisheries also provide employment to 1.6 of the 14 million Cambodians.
Fishpen culture is a possible means to increase fish production in Casamance, Senegal and to develop aquaculture without negative environmental effects. To study this possibility, a fishpen study was conducted in two dammed valleys, Guidir and Balobar in the area. Wild Sarotherodon melanotheron from 7.7 to 25.4 g and Tilapia guineensis from 7.7 to 35.0 g were stocked at densities ranging from 1.5 to 2.5 individuals/ super(m). Results are summarized in this article.
The paper outlines briefly the history of the fishery in a dam reservoir in India. The reservoir was very productive in its early years, with support from a seed farm, ice plant, cold storage and regulated entry of fishery. However, once entry restrictions were relaxed and closed fishing seasons no longer enforced, the yield of fish from the reservoir declined.
Freshwater allocation in an environment of increasing demand and declining quality and availability is a major societal challenge. While biodiversity and the needs of local communities are often in congruence, the over-riding necessity of meeting national demands for power, food and, increasingly, mitigation of the hydrological effects of climate change, often supersedes these.