The Semiglades: the collision of restoration, social values, and the ecosystem concept

Opinion article

The valuation of riparian fisheries in Southern and Eastern Africa

This paper reviews the published and gray literature concerning economic valuations of river fisheries in eastern and southern Africa, extracting the best available information on their direct economic values and on the impacts of changes in water management on this value. It then assesses the methods used and makes recommendations regarding approaches to be used in future. The review concentrates on rivers with their associated floodplains and major deltas. The values and issues associated with estuaries and lakes are not considered.

Predicting the fisheries potentials of inland reservoirs and lakes: a case study of Kubanni Reservoir, Ahmadu Bello University, Zaria

The depth, alkalinity, total dissolved solids and conductivity of Kubanni Reservoir were monitored biweekly between December 2003 and April 2004. The range values and their means were 0.8-4.64m, 42-67mg/l, 52-71mg/l and 104-142 mhos/cm; 2.8m, 42.6mg/l, 59.8mg/l and 119.6 mhos/cm respectively. Total Dissolved solids correlated significantly (P<0.05) with depth and conductivity while alkalinity correlated highly and significantly(P<0.05) with conductivity, total dissolved solids but negatively correlated with depth. The electrical conductivity was positively and highly correlated with depth while Morpho-Edaphic Index (MEI) which increased with depth decrease correlated positively with conductivity. Based on the average value of the MEI the potential fish catch of the reservoir was estimated to be 38kg/ha. This estimate was compared with other values obtained from other African reservoirs/lakes and management considerations under "private liability company" are proffered

Central area redd project [Ribble, Hodder and Lune catchments]

Redd counting is an integral part of most Fishery Officers duties. The number and distribution of salmonid redds throughout salmonid catchments provides invaluable information on the range and extent of spawning by both salmon and sea trout. A project was initiated by the Fisheries Science and Management Team of Central Area, North West Region in England in liaison with the Flood Defence function. The main objective of this project was to assess redd count data for Central Area and attempt to quantify these data in order to produce a grading system that would highlight key salmonid spawning areas. By showing which were the main areas for salmon and sea trout spawning, better informed decisions could be made on whether or not in-stream Flood Defence works should be given the go-ahead. The main salmonid catchments in Central Area were broken into individual reaches, approximately 1 km in length. The number of redds in these individual reaches were then calculated and a density per lkm value was obtained for each reach. A grading system was devised which involved looking at the range of density per km values and dividing this by five to produce 5 classes, A - E. A sixth class (F) was used where the density per Ion value was 0.00. This grading system was calculated at two levels of detail. Grades for salmon and sea trout were produced for each individual catchment and also on an Area-wide level. Maps were produced using a range of colours to represent the grade for each reach. These maps provide a highly useful overview of the status of salmonid spawning for each catchment over individual years and highlight the key salmon and sea trout spawning areas in each catchment. These maps and the associated summary data should now provide Flood Defence and Fisheries staff with a fairly detailed overview of the status of spawning in any location within the. main salmonid catchments in Central Area. Although these maps are very useful they should only be used as a guide. The current practice of consulting with the local Fishery Officer should be continued to ensure that expert local knowledge is taken into account.

Value chain transformation: Taking stock of WorldFish research on value chains and markets

The goal of WorldFish’s research on markets and value chains is to increase the benefits to resource-poor people from fisheries and aquaculture value chains by researching (1) key barriers to resource-poor men, women and other marginalized groups gaining greater benefits from participation in value chains, including barriers related to the availability, affordability and quality of nutrient-rich fish for resource-poor consumers; (2) interventions to overcome those barriers; and (3) mechanisms that are most effective for scaling up of value chain interventions. This paper aims to promote and document learning across WorldFish’s value chain research efforts in Asia and Africa. It has three main objectives: (1) to take stock of WorldFish’s past and ongoing research on value chains; (2) to draw out commonalities and differences between these projects; and (3) to provide a synthesis of some learning that can guide future work.