A simple linear regression model was used to determine variations in temperature and salinity profile in the coastal waters of Ghana in Gulf of Guinea (GOG) from four surveys, two from each hydrographic season conducted between 2000 and 2002. The model estimated an average sea surface temperature (SST) of 27.13°C for thermocline season and 22.52°C for upwelling season. The average sea surface salinity (SSS) estimated by the model for the thermocline season was 35.24‰ and the upwelling season was 35.56‰. A seasonal sea surface temperature (SST) variability of 4.61°C was observed in the GOG. This revealed that that seasonal SST variability in the Gulf of Guinea (GOG) has reduced. The changes in temperature and salinity with unit change in depth did not show any clear pattern between thermocline and upwelling seasons. Temperatures showed higher level of correlation with changes in depth than salinity. The range of temperature within the 80-metre water column was higher in the upwelling season than the thermocline season. The range of salinity however did not show any clear pattern between the thermocline and upwelling seasons. There were no significant differences in temperature and salinity between the two upwelling seasons. There were however significant differences in temperature and salinity between the two thermocline seasons. The reduction in seasonal variability of SST in the GOG has implications for marine life in the region.

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In recent times, artisanal pelagic fishery which constitute the mainstay of Ghanaian fisheries have shown a decline leading to low economic output in coastal fishing communities. Trend analyses were performed on artisanal fish catch, catch per unit effort (CPUE), number of canoes (or artisanal vessels) and upwelling index from 1990 to 2016. Pearson Correlation investigated the relationship between catch and fishing effort, number of canoes and upwelling index. Round sardinella and anchovy constituted major artisanal pelagic fish species contributing 24% and 25% to artisanal fish production respectively. Catches of round sardinella declined sharply after 2006 with an average catch over last three year constituting 17% of maximum historical recorded catch in 1992. T-test however revealed no significant differences in catches of round sardinella and anchovy. There was a decline in catch, CPUE, upwelling index and an increase in number of canoes. A relatively stronger and negative relationship between catch and number of canoes indicated the major cause of dwindling catch was the higher number of canoes. Catch however had a positive relationship with fishing effort (number of days) and upwelling index. The number of canoes increased by 44% and the average CPUE was 322 kg/day. It is recommended that number of canoes are reduced to promote sustainable exploitation of the resource. This can lead to high economic output in coastal fishing communities to improve livelihood. Ghana is one of the major fishing nations in West Africa and is bordered on the south by the Gulf of Guinea (GOG). The artisanal pelagic fishery constitutes the mainstay of the fisheries with round sardinella and anchovy as the major species. The round sardinella is exploited during the major upwelling season which occurs from July to September whilst anchovy is exploited all year round. The primary ocean dynamics in GOG relates to the equatorial upwelling and seasonal coastal upwelling along coast of Cote d'Ivoire and Ghana [1]. Sea surface temperature (SST) is an important signal of upwelling in the GOG and upwelling takes place when SST drops below 26°C for a continuous period of a fortnight. The GOG has an average SST of 22.5°C during the major upwelling season [2]. The artisanal fishery is the largest sector with higher number of vessels and contributes more than 70 percent of landed fish. It provides fish for local consumption and employ 80 percent of Ghanaian fishers. The artisanal fisheries sector in West Africa is labor intensive, operates near the shores and provides fish for local communities [3]. The artisanal Ghanaian fishery employs a multiplicity of gears and is categorized into five main gears for statistical purposes namely purse seine, beach seine, set gill net, drift gill net and hook and line. There was a total of 11,583 canoes of which 3,346 are was pursing net ("Poli/Watsa") canoes, 1,084 beach seine canoes, 1,344 hook and line canoes, 3,729 set nets canoes, 1,052 gill net ("Ali") canoes, 836 drift net canoes and 192 one-man canoe...