Floating in the sea, pushed about by winds and currents, sea jellies drift about letting their "harpoon"-studded oral arms and tentacles collect food. The fried-egg jelly (Phacellophora camschatica) is one of the larger jellies to be found along the Pacific coast of North America. The bell of this jelly can be up to 23 inches (60 cm) in diameter, and the thin white tentacles may extend for 10 to 20 feet (3 to 6 meters). Unlike some jellies that have powerful stinging cells on their tentacles to immobilize active swimmers like fish, the fried-egg jelly's tentacles and oral arms are sticky with mild stinging cells. This is largely the result of them having evolved to prey on other jellies that once captured by the tentacles can't swim strongly enough to get away.
This week's photo is a close-up of the frilly oral arms of a fried-egg jelly encountered in the chilly waters of Point Lobos State Park just south on Monterey Bay on the California coast. The thread-like tentacles typically trail out behind the animal, acting like a fishing net of sorts. When another jelly, or other prey, bumps into the tentacles, the tentacles' sticky surface and mild stinging cells snare it. As the prey becomes entangled in more tentacles, it is drawn upward toward the oral arms as the tentacles contract. Once there, the prey becomes entangled in the oral arms and is eventually digested.
The oral arms hanging beneath the main bell of the animal are reminiscent of the petty coats women used to wear beneath their skirts, but their purpose is far more deadly, to the prey at least.
This photo was taken with a Canon EF 17-40 f/4.0 USM lens zoomed to 17 mm on a Canon EOS 10D in an Ikelite underwater housing. Lighting was provided by a pair of Ikelite DS-125 strobes in eTTL mode. The exposure was set to 1/60 sec at f/22 and ISO 800.