An assessment of the vulnerability of Ghana's coastal artisanal fishery to climate change

Abstract

Considering the fact that nearly 25% of the Ghanaian people live in the coastal zone and about 10% depend on the coastal fishery for livelihood, it is likely that any changes in the production of the fishery may impact on the socio-economic lives of the people. For the past four decades, climatic conditions ha ve been found to be changing in the country. This period coincided with the conspicuous fluctuations in the landings of the most significant pelagic species exploited by the canoe fleet. This study provides an assessment of the influence of precipitation and sea surface temperature changes on yield and catch of Round Sardinella (Sardinella aurita), anchovy (Engraulis encrasicholus), Flat Sardinella (S. maderensis) and Guinea Shrimp (Parapenaeopsis atlantica). The abundance of these stocks is believed to be correlated with upwelling and sea surface temperature conditions and a local manifestation of global scale climatic changes is suspected to be taking place. It was hypothesized that climate as represented by sea surface temperature (SST) and precipitation affects either catchability or the population growth rate of each species. Forty years of climatological data (mean air temperature and precipitation) were assessed; 38 and 33 years each of hydrological data (sea surface temperature and salinity) were then used to investigate the possible relation between climatic changes and species production. Forecasts of future climate scenarios were made, and stock dynamics were simulated with an environmentally coupled dynamic surplus production model. Stock production and, to a lower extent, catchability were found to be closely tied to climatological factors. Lower catch rates of the Round Sardinella coincided with years of higher SST and the reverse was true for the anchovy. For the shrimp and flat sardine, precipitation was found to have the most substantial effect on production and total annual catchability. It was concluded that changes in climate directly affect the productivity of the ecosystem as well as its catchability and most importantly, the population growth rate of the species. For sustainable management of the fishery resources, it is imperative that climatic and hydrological parameters be incorporated into fishery management models.