Some ambient environmental conditions, food and reproductive habits of the banded lampeye killifish Aplocheilichthys spilauchen in the Kakum estuary wetland, Ghana

Abstract

The use of killifish in biological control of mosquitoes to complement other mosquito control programs is gaining interest due to the increasing development of chemically resistant substrains of mosquitoes. This study investigates the ambient salinity, temperature and dissolved oxygen as well as food habits, sex ratio, fecundity and spawning frequency of Aplocheilichthys spilauchen in Ghana in an effort to broaden knowledge of the suitability of this killifish for mosquito control. Sampling was undertaken from July 2009 to January 2010 to monitor the levels and variations in the environmental parameters and fish abundance, and also to determine the feeding ecology, fecundity and possible spawning frequency. Results suggested that lower levels of salinity favoured the population while levels beyond 4‰ were detrimental. The species preyed highly on insects and insect larvae, which constituted 80% of food consumed. Females significantly outnumbered males by almost 2:1 (χ2 = 28.57, P < 0.05), and had low fecundity (2–44 eggs). Ova diameter analysis suggested that the species spawns continuously. The better survivability of the species in freshwater pools with continuous spawning of drought tolerant eggs, and the high preference for insects and insect larvae suggest that it could be a useful candidate for biocontrol of mosquitoes.