Occurrence, age, growth pattern and sex ratio of mullet species in Lagos Lagoon

Abstract

The occurrence, age, growth pattern and sex ratio of 334 specimens of mullets collected from the Lagos Lagoon were investigated from December 2007 – March 2008. Five species of mullets were identified and the relative abundance of species was: Liza dumerilii (35.02%), Liza falcipinnis (33.83%), Mugil cephalus (27.84%), Mugil curema (2.99%) and Liza grandisquamis (0.30%). The standard length of all mullet species ranged from 8.9 – 25.9 cm (total length range was of 11.7 – 27.6 cm) and the total body weight ranged from 11.52 – 269.84 g. The frequency polygon reflected five age groups in L. dumerilii, seven age groups in L. falcipinnis, four age groups in M. cephalus and two age groups in Mugil curema. The b- values were: 2.82 (L. dumerilii), 2.97 (L. falcipinnis), 3.60 (M. cephalus), and 4.60 (M. curema). The Liza species exhibited a negative allometric growth, while the Mugil species had positive allometric growth pattern. All the species had K-values above 1 except for L. grandisquamis. The sex ratio was in favour of the female fish in all the species examined except in M. curema. The present investigation has provided an assessment of the mullet species in the Lagos Lagoon, Nigeria, with relevant information that would be useful in the exploitation, cultivation and conservation of these under-utilised resources of this coastal community