Reproduction of blackchin tilapia, Sarotherodon melanotheron, within an impounded mangrove ecosystem in east-central Florida

I investigated the reproductive biology of introduced blackchin tilapia, Sarotherodon melanotheron, over a twelve month period within a seasonally impounded mangrove ecosystem in east-central Florida, and compared the data to published accounts from native African habitats. Eggs and free embryos were collected from the buccal cavity of adult males from April to October indicating a protracted spawning season, however gonadosomatic indices suggested that most spawning occurred in April and May. The timing of reproduction was adjusted to occur immediately before temperatures reached optimal levels for juvenile growth and when increasing rainfall produced abundant food and shelter for the young. Temperatures below 24°C inhibited reproduction from November to March. The overall sex ratio was essentially 1:1. The minimum and maximum size at maturity were much larger in this study than those reported from Africa; the smallest mature male was 128mm standard length and 0.47 of the maximum size, while the smallest mature female was 145mm standard length and 0.54 the maximum size. However, because of the difficulty in aging this species and a lack of published information, it could not be determined whether the population in this study possessed a relatively early or delayed maturation compared to African populations.[PUBLICATION ABSTRACT]