Abstract:
Increased absorbance of carbon dioxide from the atmosphere has led to the changing of the chemistry of the oceans. In addition to already existing stressors, the resultant ocean acidification poses multiple threats to marine species biodiversity and goods and services and livelihoods that depend on them. The study set out to determine possible impacts of this phenomenon on the abundance and diversity of fin and shellfish species and ichthyoplankton in the artisanal and semi-industrial fisheries of Ghana, and the degree of reliance of the local fisher folks on these two fisheries. Physico-chemical parameters in the sites where fishing by artisanal and semi-industrial vessels were carried out were collected in the lean and peak seasons. Fish samples were collected, species identified, counted and diversity indices calculated for each fishery and season. A Canonical Correspondence Analysis (CCA) was used to identify which of the principal factors influenced the fish species. Fisher folks were randomly interviewed using structured interview guides on their reliance on the fishery and analysed using the Tobit Regression Model (TRM). Four ocean acidification parameters (pH, carbonate ion concentration, total alkalinity, Revelle factor) out of six principal components were identified to contribute significantly (RELATE, r = 0.955, P < 0.05) to biological variations observed in the two fisheries. A decreasing trend in ocean acidification indicators was observed for both fisheries and variations observed in species abundance between seasons and fisheries, which indicate the possible occurrence of ocean acidification in Ghanaian waters and likelihood of impacts on fish diversity. The Tobit model revealed a significant reliance (P < 0.01) of fisher folks on the two fisheries and implies that livelihoods would be impacted with occurring ocean acidification. Education and provision of alternative livelihoods for fisher folks is thus necessary in ensuring upkeep of livelihoods in the face of ongoing ocean acidification of Ghanaian coastal waters.
