CBU: Unusual sighting of a swarm of moon jellyfish, Aurelia aurita (Linnaeus 1758) in the Bras d'Or Lake, Cape Breton during the summer of 2017

Following a routine sampling event in the Great Bras d’Or Lake in July 2017, researchers discovered a huge moon jellyfish swarm. The location of the sighting was recorded and the size of the aggregation was estimated. Nets were used to collect specimens and in addition pictures were taken with an underwater camera. Examination of specimens returned to the lab revealed that this was a spawning event based on the existence of viable planula. Local and traditional knowledge exist of scattered moon jellies in this area for most summers however there has been no previous recording of such a phenomenon in this area. The site was revisited six days after the original sighting. The swarm had dispersed and only a few hundred dead and dying individuals were observed. This resource contains a record of the presence of the jellyfish at this one location.