Crystal Jellyfish     Aequorea spp.

Commonly found in Puget Sound, this moderate sized (2 to 5 inch) jellyfish is often seen floating near the surface where it's pulsating bell propels it through the water.

The bulk of the animal is composed of a jelly-like material that is transparent. Hanging down from the exterior margins of the bell are numerous stinging tentacles with which it captures its prey.  The common prey are other jellyfish and gelatinous members of the plankton which are engulfed by the mouth which is in the middle of the underside of the bell.

Inside the bell are numerous radial canals along which are attached the gonads.  This stage of the animal's life history is called a medusa which lives only from spring to fall producing larvae.  The larvae attach to a hard surface such as the underside of a floating dock and survive the winter as a polyp or hydroid, looking like a very small sea anemone.  In the spring the new medusa bud off the polyp.

The stings from the tentacles are not noticeable to most humans and so this species is often handled.  If you handle one at night don't be surprised if it emits a green glow from the margin of the bell.  This glow or bioluminescence is produced by a biochemical reaction.  The organic chemicals that produce this reaction were discovered at the University of Washington's marine laboratory at Friday Harbor on San Juan Island earning the researcher a Nobel prize.  This discovery has been commercialized and is now widely used in biomedical research.