ASSESSMENT OF THE BIOLOGY AND POPULATION STRUCTURE OF BOBO CROAKER FISH PSEUDOTOLITHUS ELONGATUS (BOWDICH, 1825) FROM QUA IBOE RIVER ESTUARY, IBENO L.G.A, AKWA IBOM STATE, SOUTHEASTERN NIGERIA

ABSTRACT The biology and population structure of Pseudotolithus elongatus was carried out in Qua Iboe River Estuary at Ibeno L.G.A in Akwa Ibom State, Southeastern Nigeria between July to December, 2024 using standard methods and procedures. A total of hundred and seventy-seven fish specimens made up of 140 males and 37 females were analyzed for sexual dimorphism, sex ratio, size distribution, reproductive investment using gonadosomatic index, hepatosomatic index and condition factor and determination of length-weight relationship. The results showed that the males were significantly more than the females with the ratio of 1.0: 0.26 and was significantly different from the expected 1:1 ratio (χ2= 15.842, p= 0.001). The genital papillae on the postero-ventral surface of the abdomen were more rounded in females than those of the males. The GSI ranged from 0.33 to 3.56 (1.258±0.04) and the HIS ranged from 0.10 to 0.88, K ranges from 0.42 to 1.43 respectively. Somatic weight decreased with decrease in condition factor (K). Length at first maturity of male and female measured at standard length showed that female matured earlier than the male counterparts. The smallest fish weighed 11.50g while the largest fish (male) was 9.6g heavier than the largest female. The smallest fish examined was male with the total length of 12.50 cm while the largest specimen was also male with Lmax of 23.50 cm and body weight of 101.80g caught in the rainy season in the month of September. The regression exponent (b) showed that males (3.018, isometric), females (2.877) and combined sexes (2.994) were negative allometric. The R2 value obtained showed a strong linear relationship between the length and weight of the species (p< 0.05). Qua Iboe River Estuary seems to be polluted as the growth exponent showed negative allometric growth pattern. Hence, proper monitoring of the ecosystem is recommended.