Dive Dry with Dr. Bill

068: In the Jungle... the Lion Sleeps

I've spent a fair bit of time recently writing two papers to present at the Sixth California Islands Symposium in Ventura Dec 1-3. This conference occurs roughly every five years. Catalina's own Dr. Bob Given attended the first one back in 1965 when I was a college freshman and probably didn't even know where the Channel Islands were! I've attended all of them since then, and have presented papers at the last three. Island residents interested in learning more about Catalina and its "neighbors" might consider attending this. Sessions will cover the marine biology, terrestrial ecology, archaeology, conservation, history and other interesting subjects about the islands extending from the Farallones in the north to those off Baja's Pacific coast in the south.

One of my papers is about the effects of our own island with its rugged peaks casting shadows on the water and shading areas where kelp might grow, especially in the late afternoon on our leeward side. I ask the question whether this "hillshading" of our coastal waters might affect the distribution of giant kelp (it apparently does). The other is on the history of the Catalina Island School for Boys (CISB) from 1928-1943. So what does this have to do with the subject of this week's column "in the jungle, the mighty jungle, the lion sleeps tonight?" While writing up this research paper, I thought back to the very first research I did here on Catalina Island back in the late 1960's while teaching at CISB, located in Toyon Bay before CIMI.

That early research looked at detached drifting mats or "rafts" of kelp as one possible way that marine invertebrates could disperse from the mainland to Catalina, from Catalina to the other islands, etc. Many marine species live in the holdfast or fronds of living kelp, and are transported with it as it travels with the currents. My students at the Toyon school would go out with me to collect the drifting "rafts" in the school launch, then bring them back to my meager lab at Toyon to "dissect" the raft, count and identify all the species we found on it. Later I would write reports of these findings which were later presented and published at one of the California Islands Symposia.

One of the species found on a raft looked like a blob of greenish jelly sitting on a kelp blade while we were out on the boat. When we put it in the school's holding tanks, a very strange creature about 3" long took shape. I had no idea what it might be, and there were relatively few good guidebooks back then. I decided to report this finding back to Dr. H. Barraclough Fell, one of my mentors at Harvard and the scientist who helped support our kelp rafting research program. I drew him a simple picture of the creature's outline with the description "it looks like a Hoover vacuum cleaner with wings."

About two weeks later I received a letter. Any of my readers remember what those are? They were an ancient form of communication back in the days when postage stamps were a few pennies (and before my classmate Al Gore invented the Internet so he could e-mail roommate Tommy Lee Jones). Dr. Fell had taken it to another expert, Dr. Ruth Turner at Harvard's Museum of Comparative Zoology, and she identified it as Melibe leonina (oops, I've used a scientific name). Fortunately this creature has a common name... the lion nudibranch! So the kelp forest (almost like a jungle) is home to this small marine equivalent of the king of the beasts.

I've written previously about my fondness for nudibranchs, the often very ornate and beautiful shell-less relatives of snails. Many marine biologists and SCUBA divers share this love. The lion nudibranch is an excellent example of everything my icon Edward F. "Doc" Ricketts and his pal John Steinbeck said about marine animals (not to mention marine biologists). It is both a terrifying eating machine and a love machine. Food and sex... what else is there to life?

Of course to be really terrified by it you have to be a small planktonic copepod or other invertebrate. This "lion" crawls along the kelp extending its big oval oral hood which sweeps the water like a net, capturing plankton and bottom-dwelling crustaceans for food. In a sense it really IS like a Hoover vacuum cleaner (or Oreck if you prefer)! Like other nudibranchs, Melibe is one of those "Hollywierd" species with both male and female sex organs. This makes "love" easy since anytime one encounters another Melibe, it will be possible to mate with it! That sure would make it easier to find a date on Saturday night. In fact while conducting my research one day off the East End, my class found thousands of these nudibranchs on drifting kelp... and every one of them seemed to be mating (although we tried not to peak)! Between 15-25 eggs are laid in a broad ribbon on the kelp.

The lion nudibranch is found from Alaska to Bahia de Los Angeles in Baja, and appears to be seasonal here on kelp during the warmer months. If dislodged from the kelp, the animal may "swim" by flexing its body. One of the kelp crabs is reported to eat lion nudibranchs, or cause them to "swim" away when attacked. In an interesting adaptation, a species of scale worm is a commensal species on these nudibranchs. A commensal species gains a benefit from another species without hurting it. How does this occur? The worm feeds on the nudibranch's fecal matter. Yes, it eats its poop. Not my idea of gourmet dining, but to each species its own. As for me, I'll feast on turkey. Happy Thanksgiving to all.

© 2003 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays.

Lion nudibranch feeding with oral hood extended; X-rated shots of
two lion nudibranchs mating in my laboratory tanks at Toyon

This document maintained by Dr. Bill Bushing.
Material © 2003 Star Thrower Educational Multimedia