Meeting Abstract
While most jellyfish are planktonic organisms as adults, actively swimming through the water column, the genus Cassiopea is primarily epibenthic, resting with its bell on the bottom and its feeding structures up into the water column. Therefore, bell contractions are rarely used for swimming in open water. In this study, we demonstrate via in situ and in vitro time-lapse imaging of Cassiopea from the Florida Keys that these animals exhibit a benthic crawling-type of movement and, using this behavior, organize into chains of individuals instead of clumping or dispersing. The mechanism for this movement is an asymmetrical lateral paddling of the bell margin. While normal swimming utilizes a symmetrical contraction of the bell towards the center of the animal, crawling involves both sides of the bell margin pushing to one side of the animal. Particle Image Velocimetry (PIV) is used to explore the potential for water flow interactions of different spatial arrangements of Cassiopea, while quantification of stinging nematocysts released into the water column when Cassiopea are disturbed allows for examination of the potential for defensive benefits of aggregation.
