Features of intercohort cannibalism of Vendace (Coregonus albula (L.)) under laboratory conditions

Abstract

Cannibalism in Vendace (Coregonus albula (L.)) was studied under laboratory conditions by exposing Vendace eggs (100) or newly hatched larvae (20) to an older individual in aquaria. Predation on the eggs was not detected whereas both biting and ingesting of newly hatched larvae were observed in 23% of older Vendace individuals. Small individuals (<100 mm in total length) were significantly more likely to attack larvae than larger individuals. Differences were also found in attack rates between individuals. The rate ranged from no attacks to attacks towards every larva exposed to the cannibalistic individual. These results confirm that intercohort cannibalism is neither an exceptional nor a universal phenomenon when freely swimming Vendace larvae are exposed to older conspecifics. Field observations and bioenergetic modelling are recommended to assess whether cannibalism plays a role in recruitment variation, especially since Vendace show a biennial cycle in the strength of their year classes.

Keywords:

• cannibalism
• Vendace
• Coregonus albula
• eggs
• larvae

Acknowledgements

We thank the staff of the Konnevesi Research Station for the valuable help during experiments and the local fishers in Lake Southern Konnevesi. Experiments were performed with permission of State Provincial Office of Western Finland (LSLH-2005-04115/Ym-23). The constructive suggestions by three anonymous referees improved the article considerably.