Habitat distribution, growth and mortality of the giant African cuttlefish Sepia hierredda were studied along the coast of Ghana in the Gulf of Guinea. S. hierredda is an economically important species in Ghana, but has backdrop in literature, except the landed catches. For the first time, the giant African cuttlefish habitat and spawning grounds were mapped and growth and mortality parameters were also estimated. In all, a total of 1,299 individuals including 180 males and 118 females were collected for reproductive biology and 1001 unsexed individuals for population parameter analysis. The study covered a period of 10 months, from January to October 2016. S. hierredda in Ghanaian waters attained an asymptotic length of 33.88 cm based on the mean length (20 cm) observed. The growth constant (K) of 0.69 indicated fast growth for the species. The life span was estimated at four years with a growth performance index of 2.89. Females attained first sexual maturity (Lm50) at 17.70 cm and the length at first capture was 16.0 cm. Total mortality (Z) rate was estimated at 2.88 yr-1, natural mortality (M) 1.31yr-1 and fishing mortality (F) 1.57 yr-1. This was evident in the current rate of exploitation (Ecurrent) of 0.56. Hence, the exploitation of cuttlefish has exceeded the sustainable limit in Ghanaian waters. It is therefore recommended that selective gears be designed for sustainable exploitation of the species, to avoid catching undersized fishes.
Key words: Habitat distribution, dorsal mantle length, growth parameters, fishing mortality, exploitation
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