Abstract:

The study of the relative yield and sex ratio of the West African fiddler crab (Uca tangeri) in Mbo river of Akwa Ibom State, Niger Delta, Nigeria, was conducted for 12 consecutive months. Uca tangeri exhibited sexual dimorphism with a sex ratio of 1.2:1.0, which was significantly biased in favour of males. The yield isopleths demonstrate the response of the crab to both variation in E (exploitation level) and Lc/L∞ (a proxy for mesh size). Yield contours with Lc/L∞ = 0.74 usually consist of four quadrants (Pauly and Soriano, 1986), each with its characteristics. The yield isopleths with Lc/L∞ = 0.74 and E = -1.62 belong to quadrant B, which implies that, large specimens were caught at high effort level.