Aspects of ecology and biology of the cichlid, Tilapia mariae from two adjacent low-brackish water lagoons in Nigeria.

Abstract

Some aspects of the ecology and biology of the spotted tilapia, Tilapia mariae from Badagry and Ologe Lagoons in Nigeria were examined between August 2006 and May 2007. The species was captured throughout the sampling period and constituted about 34.55 and 38.42% of five cichlid species in the catch from Badagry and Ologe Lagoons respectively. Whereas, the total lengths of the specimens from Badagry Lagoon ranged from 8.2 to 17.1 cm (SL, 6.5 – 15.0 cm), specimens from Ologe Lagoon had a total length of 8.9 – 18.1 cm (SL, 6.9 – 13.5 cm). The total weight ranged from 15.50 to 86.50 g and 15.00 to 105.40 g for the specimens from Badagry and Ologe Lagoons respectively. Generally, the condition factors of T. mariae from Badagry Lagoon were higher than those from Ologe lagoon. The sex ratio of 1:0.66 and 1:0.70 were obtained in specimens from Badagry and Ologe Lagoons respectively. Four gonad maturation stages were recorded in Badagry Lagoon, while three were recorded in Ologe Lagoon. Plant materials, diatoms and green algae predominated the food items consumed by the species in Badagry Lagoon, while diatoms, cyanobacteria and green algae were the most abundant items consumed in Ologe Lagoon. Adequate management of the species will enhance fish production in the sub-region. Key words: Brackish-water, Lagoon, Tilapia mariae, cichlid, food items.