Hitchin’ a ride on the Red-eye Medusa
By Jett and Kathryn Britnell
Named for the telltale ‘red eyespots’ ringing the base of its tentacles, the Red-eye medusa (Polyorchis pencillatus) is one of the prettiest jellyfish in British Columbia’s Emerald Sea. These ocelli are actually tiny light-sensitive receptors that help the Red-eye medusa stay vertically oriented in the water column as it moves about and feeds. The translucent bell averages about two to four inches (5-10cm) in height and 0.8 to 1.2 inches (2-3cm) in width with a fringe of about 120 evenly spaced, unbranched tentacles that can elongate to twice the bell length when drifting or they can contract in swimming mode.
Despite tidal movement, the nearshore range of this hydromedusa is local, typically in shallow bays with eelgrass. Divers usually see them in midwater depths of 10 to 30 feet (3-10m). They seem to favour the surface at night and seafloor during the day to feed on plankton and benthic critters such as small crustaceans, worms and amphipods, some of which are seen here hitching a ride on the red eye! Interestingly, this jelly will ‘hop’ along the seafloor stirring things up a little, most likely for a meal!
Scientists say jellyfish populations are growing rapidly in many parts of the world ocean due to a deteriorating marine environment caused by ocean warming, acidification and predator-prey imbalance. But some observers are concerned the diminutive Red-eye medusa’s numbers may be in a decline as their habitat is destroyed by such human activity as seafloor dredging, pollution run-off and also, ironically, due to specimen collection for research. Enjoy them while you can… the Red-eye may not be around forever.
Photograph taken at Browning Passage, British Columbia, using a Nikon D700 with a Nikon 105mm macro lens in an Aquatica housing fitted with dual Sea & Sea YS-D1 strobes. Exposure: ISO 200, f/32 at 1/125th second shutter speed. Photograph: © Jett Britnell – www.jettbritnell.com
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