Sound production has been widely described for territory holding fish, including cichlids, during reproductive and agonistic activities. Males of the African mouth-brooding cichlid Oreochromis mossambicus defend territories where they dig pits to attract females. Sound emissions, a series of pulses, were studied in this species to determine their association with agonistic and courtship acts. Focal observations on visual and acoustic behaviour were carried out for 8 territorial males of various sizes belonging to 5 mixed sex groups. The number of times each behavioural act occurred with and without sound emission was scored and tested for dependence. Agonistic and courtship episodes were also quantified and correlated with sound production rate. Courtship episodes were categorised into low (either 'tilt' or 'lead' occur) and high (either 'tail wagging' or 'quivering' occur) rank episodes. Sound production was significantly associated with the courtship acts 'tail wagging' and 'quivering' in all fish and with 'pit circling' and 'dig' in larger males. Courtship episodes were positively correlated with sound emission rate, though only for high rank episodes in small individuals. Sound production was not significantly associated with agonistic behaviour.
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