Length at age and length-weight relationship of Parailia pellucida of the Nun River, Niger Delta, Nigeria

Abstract

The length at age and length-weight relationship of Parailia pellucida of the lower Nun River was investigated. The modal Total Lengths (TL) (cm) for the males of age 1+ to 4+ were 6.6, 8.5, 9.8, and 11.0 with an absolute increment of 1.9, 1.3, 1.2 respectively. L_t +1 was 8.5, 9.8 and 11.0 for ages 1+ to 3+ males respectively. The modal lengths, absolute increment and Lt + 1 for the females of age 1+ to 3+ were as follows: Age 1+ was 7.4, 2.3, 9.7; Age 2+ was 9.7, 1.7, 11.4; Age 3+, had modal length only of 11.4 cm. There was increase in weight with increase in size such that while the smallest male and female specimens of 4.8 cm and 4.6 cm weighed 0.169 g and 0.452 g respectively, the largest male of 11.5 cm and female of 11.2 cm weighed 7.242 g and 5.760 g respectively. The length – weight regression trends indicated variation in the growth pattern of Parailia pellucida in the Nun River. It was negative allometry in both male (b = 2.491) and female (b =2.788).