Stock assessment of the threadfin (Galeoides decadactylus) from the Nigerian inshore waters.

Abstract

Galeoides decadactylis is a commercially important species of the family polynemidae and constituted 10-20% by weight of the total landing of the trawl fishery in the 60s (Longhurst 1964a). Between 1971 and 1985 landing figures of the fish showed a fall of 7 – 8% by weight of total fish landed (FDF and NIOMR. 1986). Length frequency distribution showed the average size of fish landed by the commercial fishing company was 23.03cm while that of the Institute’s Research vessel was 18.89cm. Catch curve analysis showed that the fully exploited length ranged between 17 and 31cm. The length at infinity (Lx) obtained was 47.75cm while the growth coefficient (Z) was 0.20. Estimated total mortality (z) was 0.36. The stock size estimates was 10,090.54 tonnes, while the maximum sustainable yield (MSY) was 52.03t and the potential yield value, 1.816.30t.