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The Gulf of Guinea CPRs were towed on 114 occasions in the Gulf of
Guinea between December 1995 and April 1999 along four routes.
Three of these routes were 'coastal': the 'GH' route from Lagos,
Nigeria to Tema/Takoradi, Ghana; the 'GG' route from Tema/Takoradi
to Abidjan, Côte d'Ivoire; and the 'GJ' route from Abidjan to San
Pedro/Cape Palmas. The fourth route, the 'GI', runs over deeper
water across the southern Bight of Benin from Douala, Cameroon to
Cape Three Points, Ghana. The location of these routes is shown in
Figure 7. Samples taken since December 1995 have been stored at
SAHFOS and await detailed taxonomic analysis. The data for
Phytoplankton Colour, however, are available for all successful CPR
tows and provide an opportunity to examine interannual variability
in phytoplankton standing stock. The mean seasonal Phytoplankton
Colour taken in each degree of longitude is shown in Figure 7. In
the first year (July 1996 to June 1997), the level of Phytoplankton
Colour was high during the upwelling period (July-September), and
remained high for the next two quarters. In contrast, in the second
and third years (July 1997 to June 1998, and July 1998 to March
1999) Phytoplankton Colour was at a maximum only during the
upwelling period. There appears to be a downward trend in the
colour in the upwelling period (July-September) between the three
years. Even with only a few years of data, significant inter-annual
variability is evident. These results from the plankton module of
the LME study of the Gulf of Guinea provide the first spatially
extensive information over a number of years of plankton
variability in the region. With other information from these
surveys, the data will be of value to estimating the carrying
capacity of the GOG fishery and understanding nearshore upwelling
events of relevance to the coastal artisanal fishery.
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| Mean Phytoplankton colour, per season, along the Gulf of
Guinea. X indicates no sampling |
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| Routes from which Data have been averaged for 1°
bands of longitude. |
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