A large Aurelia labiata, marked with horeshoe-shaped purple/pink gonads and an equally colourful fringe is a sight rarely forgotten.  Seeing an entire bay absolutely full of them, so thick as to suggest one could easily skip across the water on the top of their bells. . .well, that is disturbing.  I imagine there are other hydromedusa that form huge aggregations, but the Moon Jelly gatherings have gratefully raised a number of questions concerning their environmental impact and what might be causing this overabundance.  Everygreen College’s Marine Life course handout offers a wonderful description of the species as well as a possible explanation and warning. “Dense aggregations of A. labiata have been linked to increased nutrient runoff of anthropogenic origin. Jellyfish blooms credited to eutrification affect the composition of zooplankton, as well as, larger organisms in the water column. There is increasing concern that commercially important fisheries are being affected and will be further threatened due to lack of available bait fish and increased jellyfish populations.”