Penaeus notialis (Pink Shrimps): Length-Weight Relationships and Condition Factor in Lagos Lagoon, South West, Nigeria

The Length-Weight Relationship (LWR) and condition factors (K) of 600 pink shrimps (Penaeus notialis) obtained from Makoko Jetty off Lagos Lagoon between January and June, 2009 were studied. The carapace length of Penaeus notialis ranged from 2.0 cm to 12.1 cm and 1.4cm to 11.5cm in females and males, respectively. The slope or regression coefficient (b) obtained for Carapace Length-Total Length Relationship ranged from 0.0001 in combined sexes to 1.3889 in males while the intercept (a) varied between 0.4754 and 0.8416. The value for ‘b’ and ‘a’ in Carapace Weight-Total Weight Relationship of P. notialis was highest in females and males, respectively. In the Carapace Length-Total Weight Relationship, the males’ P. notialis showed the highest regression constant (a) of 1.2345 and regression coefficient (b) of 0.8059. Generally, the values of the regression coefficient were lower than 3.0 for males, females and combined sexes, reflecting a negative allometric growth of the P. notialis. The results showed that there were differences in the condition factors for males and females. The lowest ‘K’ value for the female species was found in size group 7.5-8.4, while the highest ‘K’ value was obtained in size group 6.5-7.4. The male species had K values ranging between 0.18 and 80.29. There was variation in condition values for the combined sexes as the size group 1.0 - 1.4 had the highest K-value and size group 6.5 - 7.4 had the lowest K-value.