A geographic information system (GIS)-modeling of fish production in the Stratum VII of the Volta Lake was undertaken with the objective of investigating temporal changes and modeling fish production into the future. Parameters used included number of canoes, number of fishers, and water level. Stratum VII of the Volta Lake is currently one of the areas with the highest fishing activities, the largest fish market at Yeji and relatively a research center. Nevertheless, the lake has faced many setbacks due to poor management and monitoring. In order to combat these challenges, this study was conducted to investigate the temporal changes and forecasting production of Stratum VII of the Volta Lake using Geographic Information System. Long term field data from 1970 to 1998 on fisheries were acquired and analyzed for modeling fish production from 1970 to 2060, using ArcGIS management tools and model builder. A hind cast was first performed to validate the model. The model, “CPUE model” predicted a depletion of the fish of Stratum VII by 2055 with a maximum of 22,779 tonnes at a fishing effort of 9,826 canoes and a CPUE of 10.76 kg/canoe/day in the year 2005. Long and short term data were also compared in the Stratum VII. The R2 values of the correlation of the number of fishermen, number of canoes and the water level over the years are high (89.9%, 78.21%) and moderate (50.71%). These correlations showed a continuous increase in the fishing effort and decrease in the water level; trends that impact negatively on the fish production over the years. This study has established appropriate mechanism for incorporating field data into a GIS database to support fishery management in the Volta Lake.

 

Key words: Geographic information system (GIS) modeling, CPUE model, temporal changes, fish production, fishing effort.