Mafia island and Tanzania fishery ground is rich in variety of vertebrates and fish stock. Because of diversity and variety of these marine resources it is experiencing an increase in fishing effort particularly fishermen, fishing vessel and various fishing gear. This resulted from increase in indigenous and migrant’s fishermen and forces raise complexity in management. To reduce over exploitation burden the maximum level of effort enabling sustainable exploitation has to be determined to support measures like introduction of protected marine areas, restricting destructive gears and beach management unit already taken.
This study examined the sustainable exploitation of finfish particularly in Mafia Island fishery. Using yearly catch and fishing effort, the effect of fishing effort on stock size and maximum sustainable yield were evaluated, also it determined gear used in fishing finfish in Mafia Island fishery in Tanzania. The study was carried out using Ordinary Least Square (OLS), on time series data from 1989 to 2009 for Mafia Island. Also survey data on catch and inputs used in fishing was collected to analyze effect of gear and other inputs in finfish production function of Mafia Island. After evaluating the finfish fishery for the period of 1989 to 2009 its evident that overfishing problem is existing and fishery has not yet been managed for economic efficient. Most of fishermen concentrated along the shore using local vessel with poor technology. The effort in 2009 in Mafia Island was 18% higher than required to harvest maximum sustainable yield (MSY). And result from Mafia finfish production function suggests that an increase of fishermen, fishing time, quantity of fishing net, width and type of fishing vessel will improve fishing activities. This is more likely because Mafia fishery ground is not bounded to inshore only where 85% of traditional fishing vessel concentrated, there is a wider chance of expanding fishing to virgin offshore fishery ground not yet exploited. This may possibly be achieved after improving technology on fishing vessel and gear that could carry more fishers to fish offshore. Thus the present study calls for policy intervention to rescue inshore stock from existing high fishing pressure by motivating offshore exploitation.
Key words: Sustainable exploitation, Maximum sustainable yield, Overfishing, Catch per unit effort, Sustainable effort level
