Abstract
The tiger shrimp, Penaeus monodon (Fabricius, 1798) was studied in Okoro River estuary, Southeastern Nigeria between the months of April, 2018 to March, 2019. The sex ratio showed sexual inequality (0.82:1 ratio) in favour of female. The population structure revealed that the number of females (112) far outnumbered the males (91). The results of biometric analyses including length and weight of males, females and pooled population showed 116.25-224.08 (189.76±10.06) mm, 124.38-257.56 (197.22±12.78) mm and 116.25-257.56 (194.06±7.85) mm range of length with 15.16- 92.78 (67.62±7.71) g, 27.81-137.67 (78.69±16.41) g and 15.16-137.67 (65.39±8.15) g of weight respectively. The female population exhibited higher size structure than the male counterpart. The morphometric structure of female was significantly different from that of the male shrimp (p<0.05). The coefficient of determination (R2) 0.7984, 0.9935 and 0.6795, intercept (a) 0.00004352, 0.00000506, 0.00000944 and slope or growth coefficient (b) 2.59, 2.99 and 2.71 was obtained for male, female and pooled shrimp population. The value of regression coefficient (b) was < 3.0 that shows negative allometric growth of the studied population. The growth coefficient (b) was not significantly different from the isometric growth of b =3. The condition factor of Penaeus monodon shrinks as the shrimp increases in size. The size of the shrimp is a determining dynamic or an exponential index of condition factor. The values of welfare condition (K) was 0.98 for male, 0.99 for female and 0.95 for pooled population which revealed that the tiger shrimp, Penaeus monodon in Okoro River Estuary, Southeastern Nigeria was not in good welfare condition (K<1) and this calls for apt management of the stock.