Results
The model fitted reasonably well for all the above stocks selected (Figures 2.6.2a,b). A summary of the results of the assessments is presented in Table 2.6.2. For
Sardinella aurita the current biomass level B
cur of the stock is less than the biomass at B
0.1, although the current fishing mortality for the
S. aurita is less than FMSY (F
cur/F
MSY= 58%) that will bring the stock to sustainable levels. The model fits reasonably well the data for
S. maderensis (Table 2.6.3). The current biomass is 10 percent less than B
0.1 and the current fishing mortality is 10 percent higher than the fishing mortality that will bring the stock to a sustainable level.
Table 2.6.2: Summary of the results for the
Sardinella aurita and
S. maderensis in the western stock
Stock/abundance index |
Bcur/B0.1 |
Fcur/FSYcur |
Fcur/FMSY |
Fcur/F0.1 |
S. aurita (West/CPUE Ghana inshore) |
58% |
43% |
58% |
65% |
S. maderensis (West/CPUE Ghana artisanal) |
90% |
110% |
112% |
124% |
B
cur/B
0.1: Relationship between the estimated biomass for the last year and the corresponding biomass at F
0.1.
F
cur/F
SYcur: Relationship between the fishing mortality coefficient observed over the last year of the series and the coefficient that would provide a sustainable yield at the current biomass level.
F
cur/F
MSY: Relationship between the fishing mortality coefficient observed over the last year of the series and the coefficient that would provide a sustainable yield over the long term.
F
cur/F
0.1: Relationship between the fishing mortality coefficient observed over the last year of the series F
0.1.