Know Your Neighbours: Beware the Blobs
October-November 1998
This is an article from WaveLength Magazine, available in print in North America and globally on the web.
by Bryan Nichols
They drift by our kayaks all the time, attractive but bizarre aliens pulsing gently below the surface. The Northwest has an excellent collection of what our ancestors called " jellyfish". What? You do too? Of course they aren't fish and biology is not the right field to be retro in. Save it for your fashion sense. We'll call them sea jellies. But what the heck are they anyway? In order to name them, we need to know:
TAXONOMY (What are they and who are they related to?)
This is a complicated question because they belong to at least three different phyla, and phyla are huge divisions. One group is even in the same phylum as we are! Time to engage those (um, hopefully) active tongue muscles and wrap them around some Latin.
. Cnidarians (Phylum Cnidaria) Most jellies belong to Phylum Cnidaria, named after the Greek word for nettles. Like the sea anemones and hydroids in the last issue, they have stinging cells. In the Northwest, these jellies can be either -hydrozoans (the drifting sexual form of hydroids, which are normally attached to things) or scyphozoans (true jellies).
. Ctenophores (Phylum Ctenophora) You will also see comb jellies floating around out there. They belong to Phylum Ctenophora (combs) and do not sting or pulse like cnidarians.
. Chordates (Phylum Chordata) Finally, you might run into salps, which may not look it, but are chordates like us.
ANATOMY How do they work?)
Cnidarians are simple but effective predators, using their stinging cells to subdue prey and then eat it. Ctenophores use sticky tentacles to grab small plankton. Unlike cnidarians, they have a two way digestive tract to process it. Salps on the other hand, are fairly complex. They have bilateral symmetry (a front and back) and a little blob of nerves you could generously call a brain.
ECOLOGY (What do they do?)
Basically they just drift around and eat things that make the mistake of bumping into their tentacles or getting sucked into their siphons. Unlike most kayakers, sea jellies are planktonic - they drift where the winds and currents take them. Because of feeding and breeding fluctuations they can be very abundant one season and impossible to find the next. Most are more common in summer.
Now then - while you're out there amidst them, the question is should you really beware the blobs? Fortunately our Northwest jellies tend towards peaceful coexistence with us. It's a different scene in tropical waters, where frolicking with the jellies can be extremely painful and might even paralyse and drown you. If you're heading south for some warm winter paddling, grab a guide and get familiar with Portuguese man-o-wars and sea wasps (box jellies). You'll want to know what they look like so you can admire them carefully.
There is an invaluable new guide out on Pacific coast jellies of all types - see the book review. Here are ten of its jellies you'll want to bump into if you do much Northwest paddling.
Lifelist #3 - Northwest Sea Jellies
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MOON JELLY
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WATER JELLY
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LION'S MANE JELLY
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SEA GOOSEBERRY
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BELL JELLY
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HELMET COMB JELLY
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FLOWER JELLY
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SAIL JELLY
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SALP
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CLINGING JELLY
For more info I recommend the book Pacific Coast Pelagic Marine Invertebrates. See my review of this book below.
JELLY BEINGSThis beautiful book from Sea Challengers is unique - an accurate, comprehensive guide to sea jellies of all sorts in full color. If you spot a jelly anywhere on the West Coast, odds are it'll be in this book. If it's not, one of you is very lost. The authors are jelly experts - professor Claudia Mills has written numerous academic papers on them and David Wrobel is an accomplished jelly photographer and manager at the Monterey Bay Aquarium. THE GOOD STUFF The book starts with some jelly biology basics, including what they are, what role they play in the oceans and how to tell the major groups apart. This is followed by a brief but immensely helpful and interesting section of tips - how to avoid being stung, the best ways to observe jellies (from boats, scuba, docks and aquariums), how to temporarily collect them and finally - how to photograph them. There is a helpful pictorial glossary of parts showing eight different types of jellies with their anatomy labelled. The bulk of the book contains a photo and description of each species (including ID notes, natural history, range and habitat). The photos are usually in color and you won't believe the colors - that surreal jelly blue is complimented by a dazzling array of reds, oranges, pinks and yellows. Complex bells, arrays of tentacles and all manner of spots, dots and rings make for some stunning images. The text is fascinating, particularly the natural history notes as most of these jellies tend to be predators with complicated life cycles. Because of their free floating nature, many species can be found throughout the world, making this book helpful nearly anywhere. A welcome bonus at the end is a list with explanations and origins for all the scientific names. Because so few of the jellies have common names these explanations are very helpful as well as interesting - be sure to look up Polyorchis pencillatus. NITTY GRITTY IF I WERE EDITOR TAKE IT HOME? Though it might seem a bit technical or specific for the average person, it makes for an excellent reference for your shelf. Divers, boaters, tidepoolers and especially paddlers (who are often in the best position to see jellies) invariably come across jellies that aren't in the brief listings of more general guides. Skim the excellent photos and descriptions in this book and the next time you're on the water, your eyes will skim the surface for these exotic and beautiful blobs. GORY DETAILS |
Bryan Nichols is a Nanaimo biologist and kayaker who can assure readers that Cyanea is a poor and painful substitute for raspberry jelly regardless of how hungry you are.
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