Côte d'Ivoire
Annual statistics on catches by industrial seiners are available for the period 1966 to 1986 (Table 3). Inaccurracies derive respectively from the assessment of the share of S. aurita and of S. maderensis in the multispecies catches and from uncertain estimates up to 1979–80 with respect to the average weights landed.
Concerning the artisanal fishery data, estimates for the period 1979–1984 are available for Vridi only, whereas those of 1983–1986 cover the whole coastline (including Vridi).
After the 1972 collapse of S. aurita and a slight recovery in 1976 and 1978, there has been a decrease in catches in 1979, followed by a sharp rise to record levels in 1985 and 1986 (except in 1984 marked by a substantial loss). As regards the 1983–1986 period when artisanal catch estimates concerned the whole coastline, it is noted that the share of the Côte d'Ivoire artisanal fishery is very important and even exceeds that of the industrial fishery with the same trend for both sectors.
Ghana
Data are available for the years 1963 through 1986 and for the canoe, the semi-industrial and the industrial fisheries (Table 3) (in that table industrial fishery designates semi-industrial fishery plus industrial fishery proper). Additional data on catches and effort are given in Appendix 7.
Industrial catches data are not always sufficiently accurate because of ill-defined Sardinella species (called either “herrings” or “mixed sardinellas”). This lack of differentiation between S. aurita and S. maderensis was observed for 1974–1977 and 1980–1986 (except 1983); therefore, the Working Group deemed it necessary to make a distinction between the two species. Their respective share in the catches of the Poli/Ali canoe fleet and the semi-industrial fleet was analysed and the average value of the two shares calculated for each year (with the exception of 1981–82 for which a weighted value was indicated).
As from 1980, S. aurita catch trends are approximately identical to those observed in Côte d'Ivoire, with peak values recorded in 1985 (54 072 t). Ghanaian fisheries are dominated by the artisanal sector which is 2 to 10 times more productive than the industrial sector.
| Year | S. aurita | S. maderensis | Year | S. aurita | S. maderensis |
|---|---|---|---|---|---|
| 72 | 96 | 4 | 80 | 72.9 | 27.1 |
| 73 | 36 | 64 | 81 | 64.4 | 35.6 |
| 74 | 19.8 | 80.2 | 82 | 67.6 | 32.4 |
| 75 | 6.4 | 93.6 | 83 | 87.8 | 12.2 |
| 76 | 54.7 | 45.3 | 84 | 77.8 | 22.2 |
| 77 | 56.5 | 44.5 | 85 | 78.5 | 21.5 |
| 78 | 83.4 | 16.6 | 86 | 70 | 30 |
| 79 | 57.4 | 42.6 | nbsp; | nbsp; | nbsp; |
Togo
The available statistical series covers the period 1976 to 1986 (Table 3). Before 1983 data on catches were rather under-estimated because the different features of fishing activities (except those in the port of Lome) were not known in detail (beach seine fishery).
It is noted that the volume of catches was particularly high in 1986 (3 979 t) as compared to the other figures of the time series and also that variations are not in concordance with those of Côte d'Ivoire and Ghana (artisanal sector).
Benin
With only a two-year series (Table 3) available, the analysis can be only limited.
Côte d'Ivoire
Data on catches by Côte d'Ivoire seiners are available for the period 1966–1986 (Table 4); however, a problem is posed by the non-differentiation between species as in the case of Sardinella aurita. Concerning the artisanal fishery, the same series as that for Sardinella aurita is available but catches for the years 1979 through 1982 are underestimated.
There are fewer fluctuation in the Côte d'Ivoire catches of S. maderensis than in those of S. aurita and it is estimated that they ranged between 10 and 25 000 t throughout the time series. It is noted that the volume of artisanal catches became important only since the early 1980s and that they are now comparable to catches by the seiners.
Ghana
The Ghanaian series covers the years 1971–1986 for both the artisanal and the industrial sectors (Table 4). Artisanal catches are much higher than catches by the industrial fleet and have remained at a rather stable level since 1977 (except for a drop in 1984 and a peak in 1985), ranging between 10 000 and 15 000 t. Industrial catches were always below 2 500 t, except for 1975.
Togo
A ten-year series (1976-1986) is available but Sardinella aurita catches are underestimated. As regards catches of S. maderensis, although quite important in the overall catches, they never reached 1 500 t (Table 4) during this period.
Benin
The species is important in the catches of Benin but only a two-year series is available (Table 4).
Côte d'Ivoire
The species is present in the Côte d'Ivoire waters but was a secondary resource and exploited solely by the canoe fleet (Appendix 3).
Ghana
Available data on catches cover the years 1972 through 1986 (Table 5). Exploitation of this species is by the artisanal sector (with however a small contribution by the industrial tuna fleet which catches 500–1 000 t of anchovy for use as bait); anchovy is the dominant species in artisanal catches when seasonal high catches of S. aurita (Figure 9) are recorded.
There are considerable fluctuations in catches (from 14 000 to 68 000 t) throughout the time series, with a peak in 1981–82.
Togo
The available ten-year series (Table 5) shows the predominance of this species in the Togolese fisheries. However in 1986, and for the first time since 1976, Sardinella aurita catches were higher than those of Engraulis encrasicolus. Generally there has been a substantial growth in catches as from 1983 and until the sharp drop of 1986.
Benin
The important reduction which affected the whole region in 1985 and 1986 is also evidenced in the two-year series available (Table 5).
Côte d'Ivoíre
Catches by seiners were significant between 1966 and 1974; this was followed a long period when Scomber japonicus totally disappeared from Côte d'Ivoire waters. Since 1984, it has been recovering, at an increased rate in 1986 (Table 6).
Ghana
The available industrial data series cover the period 1972– 1986 for the industrial sector (with a breakdown between seiners, small trawlers and large trawlers (Table 6) and the artisanal sector). Since 1973, there has been a sharp decrease in catches by both fleets though less marked in the artisanal sector. This was followed in 1986 by a considerable growth, more particularly in the artisanal catches (from 45 to 16 000 t).
Togo
Data of Table 6 cover the period 1975–1986 and apply equally to Scomber japonicus and to Scomberomorus tritor. The 1983 to 1986 values do not disclose any clear trend.
Benin
Scomber japonicus has not been recorded in sufficient quantities, at least over these past years.
