Frame of reference is everything. From the perspective of sampling surf zone fishes, jellyfish in the surf tend to be an irritant. They foul lines, and in large numbers, they make sampling impossible. That’s one perspective. From the point of view of the naturalist wandering along the sandy beaches, jellyfishes are mysterious delicate creatures, so beautiful they challenge our descriptive abilities. Bound to the shore, our exposure to jellyfishes occurs only when surf washes them onto the beach, and we look forward to opportunities to get to know them. I’m in both camps.
This is a little hydrozoan called the red-eyed medusa, Polyorchis penicillatus. This little medusa is featured on the cover of McLachlan’s Fieldbook of Pacific Northwest Sea Creatures. Good luck finding that one, it’s out of print. The red-eyed medusa is fairly common on Northern Oregon beaches, but they are easy to miss because they are so small, and in the driftline, they look like little more than clear 1-inch blobs. If you happen to have a finger bowl handy, and I’m sure you do, gently place the little red-eye in some sea water. If you’ve picked a live one, you are in for a treat. The pulsing transparent bell shows all the internal anatomy and the eye-spots at the base of the tentacles immediately catch your eye. I still remember the first one I observed this way; I had no idea it would be so lively.
The sea nettle, Chrysaora fuscescens, is another commmon TOS jellyfish. It’s a large brown scyphozoan, usually 8 or more inches in diameter when it washes up on the sandy beaches. Rebecca Helm, at Jelly Biologist, wrote a post on her blog a while back that helped me identify this one. She has a great website and if you love jellyfish you should check it out.
Another large scyphozoan is the moon jelly. It washes up on the beach fairly frequently. Ricketts and Calvin mention that the gonads, the horsehoe-shaped features near the center, in the thickest part of the bell, are yellowish in the female and lavender in the male. Looks like at least two of the moon jellies featured above are males. I’ll be checking out the color of moon jelly gonads from now on.
Jellies aren’t the only gelatinous sea creatures you’ll find on the outer shores. I’ve previously written about comb jellies and salps which are also commonly encountered. A great Pacific jellyfish resource is The Jellies Zone and, for a world-wide perspective, you can also try out the Jellywatch mobile app; it’s pretty cool.
You don’t see this everyday. A few months ago I found a jellyfish display at the airport in Portland, Oregon. It’s a permanent jellyfish exhibit honoring those affected by the 2011 tsunami in Japan.
McLachlan, D. H. and J. Ayres. 1979. Fieldbook of Pacific Northwest Sea Creatures. Naturegraph Publishers.
Ricketts, E. W. and J. Calvin. 1968. Between Pacific Tides. 4th ed., revised by J. W. Hedgpeth. Stanford University Press.