E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Diet:

Medusae are known to prey on zooplankton (copepods, larvaceans and cladocerans, and also a variety of meroplankton) and some fish larvae (Purcell 2003). Medusae of this species are also reported to have major impact on Atlantic herring yolk-sac larvae in the Baltic Sea. (Lynam 2010). This species is reported by Purcell (2003) to consume mostly hard-bodied prety (e.g. crustaceans).

Reproduction:

The Monterey Bay Aquarium provides the following information on reproduction in moon jellies: “the adult male moon jelly releases strands of sperm, which are ingested by female moon jellies. After fertilization, larvae settle on or near the seafloor and grow into polyps. Polyps alternate between feeding and reproductive stages for up to 25 years. In the reproductive phase, polyps launch buds of cloned juveniles, known as ephyrae, which grow into adult medusae.” (Monterey Bay Aquarium 2010). This species has been observed to migrate directionally in British Columbia, and maintain breeding aggregations in isolated inlets (Dawson and Jacobs 2001).

Notes:

Life span in this species in Roscoe Bay, BC, was estimated by Albert (2005) as greater than one year, with 40% likely living two years or longer. Medusae remain in the sheltered Roscoe Bay throughout the year, with some lost from the bay as a result of tidal flushing: juvenile medusae in this study formed 30-40% of the population. Population densities in Japan have been estimated as 13.4 medusae m–3 (Purcell 2003).