Abstract:
African cichlids are important constituent species in tropical inland fisheries and Oreochromis mossambicus supports profitable fisheries in many countries of the world. This species exhibits elaborate courtship behaviour. Building of spawning nests by males, aggressive behaviour and breeding colouration are important behavioural patterns of this species associated with reproduction. As O. mossambicus is found in reservoirs of Sri Lanka which are situated in agricultural areas of the country, reservoir populations of this species are vulnerable to exposure to agrochemicals at least at sub lethal levels. As ‘Roundup™’ is one of the widely used herbicides in the agricultural areas of the country, the present study was undertaken to investigate its impacts on territorial behaviour of O. mossambicus.
Adult O. mossambicus collected from the wild was acclimatized to laboratory condition and exposed to sub-lethal glyphosate concentrations (0 ppm, 5 ppm, 8 ppm and 10 ppm). The territorial behaviour of males measured as intensity of colour change, chasing distance, chasing occurrence, area of territory maintained by nest builders, dorsal fin erection and status of the bites has altered significantly in the aquaria with all three concentration of herbicide.
