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RP2E INRA Université de Lorraine

Behavioural analysis of intra-cohort cannibalism in early life stages of fish.

Behaviour 2017, 31 juillet - 04 août, Estoril, Portugal

Colchen, T., Teletchea, F., Fontaine, P., Pasquet, A.

2017

Cannibalism is the act of killing and consuming a conspecific individual, irrespective of its stage of development. It can be defined as an intra-specific predation. It is a major bottleneck in larviculture, and particularly for pikeperch (Sander lucioperca). Several environmental, nutritional and populational factors have been studied; yet none allowed to completely supress it. We supposed that it could be due to one or several individual’s variables that external factors cannot completely regulate. We focused on two individual’s variables that might explain cannibalism: personality and the onset of ichtyophagy, through two experiments. The main goal of the first experiment was to highlight the possible link between cannibalism and personality. We compared cannibals (n=25) to individuals randomly sampled in the tanks (n=42) of the same age (from 32 to 52 days post-hatching (dph)) with two behavioural tests: an exploration test in cross-maze and a sociability test. We showed that there was no correlation between cannibal’s status and their personality. The second experiment aimed at evaluating the relationship between cannibalism and the onset of ichtyophagy. We compared cannibals (n=50) with non-cannibals (n=50) of the same age (from 16 to 33 dph) in two tests: a cannibalism test where tested fish was confronted to three congeners during 20 minutes and an ichtyophagy test where fish was confronted to three zebrafish (Danio rerio) as prey during 20 minutes. Results will be presented during the congress. Both experiments highlight the significance of behaviour analyses in trying to better understand cannibalism that has never been taken into account until now.

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