4.1 Ivory Coast
4.2 Ghana
4.3 Togo
4.1.1 S. aurita
Annual catch statistics are available for the industrial seiner fleet from 1963 to 1978 (Table 2). Data are imprecise regarding the separation of the two sardinella species until 1965 and calculation of average weight of crate throughout the whole period.
Since the period of collapse of the stock (1973-1975), total catches have been increasing. Analysis of catches by sector indicates that in the western Ivory Coast they were low from 1966 to 1970, sizeable during the two years preceding the collapse, and high during the last three years (Table 3). Reduced catch of the Ivorian seiners in Ghanaian territorial waters is due on one hand to changes in the country’s law and on the other hand to a shifting of the fishing effort to S. maderensis stocks located further west.
Bait catches by tuna boats and also S. aurita catches by artisanal seiners are insignificant (ORSTOM, 1976) and have been excluded. However, the growth of this type of fishery makes initiation of a study on at least the landings important.
4.1.2 Other species
Data on S. maderensis and Scomber japonicus catches from 1966 to 1978 are available for the purse-seine fleet (Tables 4 and 5). Off the Ivory Coast flat sardinella (S. maderensis) catches are similar to those of S. aurita before the collapse of this species. Since then they have remained high (Figure 3); an analysis of the evolution of catches within each sector would be interesting. Anchovy (Anchoa guineensis) and triggerfish (Balistes capriscus) catches are insignificant (Tables 6 and 7). The latter species is discarded in large quantities by Ivorian trawlers and purse seiners though this does not correspond to a high mortality rate as Balistes capriscus has a high survival rate. The quantity of discards is not known.
4.2.1 S. aurita
Annual catch data are available for the sardinella fleet and the artisanal fishery (all types of gear included); the catch of the latter being the larger (Table 2). Catches of all sardinella boats are recorded whereas for the artisanal sector there is a stratified sampling scheme (region and gear) to estimate the catches. The raising factors used to estimate catches prior to 1968 are not very precise.
The overall increase in total catches is the same as observed in Ivory Coast.
4.2.2 Other species
Annual catch figures of S. maderensis, S. japonicus, A. guineensis and B. capriscus are available, both for the artisanal and the industrial fleets (Tables 4, 5, 6 and 7), from 1972 to 1978. During the period of the decline of the round sardinella the artisanal fleet concentrated on the flat sardinella, and especially anchovies, using small mesh nets (poli). It should be mentioned that catches of these two species have remained high in recent years, despite the apparent recovery of the S. aurita stock; the same feature has been noted in Ivory Coast for S. maderensis (Figure 3).
The B. capriscus and mackerel catches are largely from trawlers. For the latter species, larger catches were taken by the seiners in 1972 and 1973, as was observed in Ivory Coast.
4.3.1 S. aurita
Data available for 1976-1978 indicate small catches (Table 2 and Appendix 3). Data for the preceding years are likely to be similar.
4.3.2 Other species
S. maderensis and B. capriscus catches have also been small in recent years (Tables 4 and 7). S. japonicus catches have not been estimated but they must also be very small. A. guineensis landings will be larger than those of S. aurita.
