The behavioural response of an estuarine teleost (Cape stumpnose Rhabdosargus holubi) to angler bait collection in two adjacent Eastern Cape estuaries, South Africa

Abstract

Reports of learned behavioural adaptations of wild Cape stumpnose Rhabdosargus holubi (family Sparidae) were investigated in two estuarine systems in the Eastern Cape Province, South Africa. Underwater observational trials using video cameras demonstrated that fish rapidly responded to bait collection activities in the East Kleinemonde Estuary but not in the West Kleinemonde Estuary. By simulating the visual and auditory cues associated with the activity alone, evidence suggested that fish in the East Kleinemonde Estuary have learnt to associate these cues with the activity, likely allowing individuals to identify and respond to this novel foraging opportunity. It is suggested that historical rates of bait collection within these estuaries is likely the cause for differences in the fish behaviour between estuaries; furthermore, social learning in fish may play a role both in perpetuating learned behaviours in the systems where they occur, and learned behaviour may potentially be shared to new systems via fish migration. This study presents a rare example of natural behaviour conditioning of wild fish to an anthropogenic niche. Further investigations into the cognitive and behavioural processes that allow wild animals to respond to human disturbance should be expanded to better account for and manage the wide-ranging impacts of human disturbance.