Food approach conditioning and discrimination learning using sound cues in benthic sharks
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The marine environment is filled with biotic and abiotic sounds. Some of these sounds predict important events that influence fitness while others are unimportant. Individuals can learn specific sound cues and ‘soundscapes’ and use them for vital activities such as foraging, predator avoidance, communication and orientation. Most research with sounds in elasmobranchs has focused on hearing thresholds and attractiveness to sound sources, but very little is known about their abilities to learn about sounds, especially in benthic species. Here we investigated if juvenile Port Jackson sharks could learn to associate a musical stimulus with a food reward, discriminate between two distinct musical stimuli, and whether individual personality traits were linked to cognitive performance. Five out of eight sharks were successfully conditioned to associate a jazz song with a food reward delivered in a specific corner of the tank. We observed repeatable individual differences in activity and boldness in all eight sharks, but these personality traits were not linked to the learning performance assays we examined. These sharks were later trained in a discrimination task, where they had to distinguish between the same jazz and a novel classical music song, and swim to opposite corners of the tank according to the stimulus played. The sharks’ performance to the jazz stimulus declined to chance levels in the discrimination task. Interestingly, some sharks developed a strong side bias to the right, which in some cases was not the correct side for the jazz stimulus.
KeywordsElasmobranch Behaviour Cognition Associative learning Personality Hearing
This research was funded by the Department of Biological Sciences at Macquarie University, and CVP was supported by an Endeavour Postgraduate (PhD) Scholarship. We thank the members and interns of the Fish Lab and SIMS for husbandry assistance, Jack Gruber for help running the experiment, Drew Allen for advice on statistical analysis, and Vera Schlüessel and two anonymous reviewers for their insightful comments.
Compliance with ethical standards
Conflict of interest
The authors declare they have no conflict of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. This work was approved by the Macquarie University Animal Ethics Committee under ARA 2014-003.
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