Dive Dry with Dr. Bill

#134: Got the Itch? Scratch It!

My upcoming DVD "Munching and Mating in the Macrocystis" contains a number of "messages" for divers and other viewers (it is an educational video after all!). One such message is that to really gain an understanding of the marine environment and ecosystems, divers should slow down and really look carefully. Of course we all realize that may be difficult for divers from the "big city" where the pace may be more hectic, and it is hard for them to unwind quickly here. However, it is essential for a real understanding of the many underwater critters and their interactions.

Another "message" is that one should not overlook the "common" species by focusing strictly on locating the rarer ones. As any "collector" will tell you, "rarity" confers a certain value whether it be a postage stamp, a coin, an antique vase or a fish. Although I do a little "collecting" myself, I believe an understanding of the common species in an ecosystem is more important. By their very numbers, common species usually exert a more significant impact on ecosystem dynamics than rare ones. Of course if environmental conditions change in the future, the common may become rare and the rare common!

I often watch these "common" species for signs of unusual behavior... therein lies my "rarity." Garibaldi, kelp or calico bass, blacksmith and wavy top snails are all commonly encountered by any diver with their eyes halfway open (remember coffee is a diuretic and dehydrates divers). Too often a diver is "satisfied" with just noting the presence of the common types and moving on. Divers who are photographers or videographers more frequently look for interesting interactions to create more spectacular images.

One good example is the giant kelpfish. These are common in our dive park and might be "overlooked" because of that. However they are a very interesting species in many respects. First the color variations can be significant... bright yellows, lime greens, boring brown, rusty red, etc. Second, they can frequently be seen mating if you know what to look for. As an underwater voyeur, I'm always interested in any mating behavior I can observe there. I do draw the line topside... late at night my telescope and binoculars are strictly for looking at the moon and stars, not the windows of the buildings across the canyon! I promise. I like my ladies up close and personal (so why is it they always run in the opposite direction?).

In my video I depict many interesting examples of common species exhibiting unusual behavior or interactions. One behavior involves giant kelpfish who have the itch! Parasites are very common in the underwater environment, and can create a fair degree of discomfort. The giant kelpfish appears to have parasites that attach to the very sensitive gill region of the fish. Now our fine finned friends don't have hands, so it is very difficult to scratch that tender region.

The solution to this itch often comes in the form of a "parasite picker." Usually this service is provided by a senorita (or a senor?) fish which has a pointed snout that can be inserted into the gill opening to grab the offending critter. Senoritas are well adapted to fill this important role as cleaners for many species. Usually I see them picking parasites off the outer surfaces of other fish, especially garibaldi. On numerous occasions I've observed and filmed senoritas approaching giant kelpfish that were "posturing" to attract cleaners. Occasionally the kelpfish opens its gill cover as the senorita approaches. The senorita then enters the open gill cavity and picks at the parasites there. The usual reaction by the kelpfish is a sharp twitch, suggesting that although beneficial it may also be a bit painful!

Although senoritas are another common species, sometimes they are not around to take care of the kelpfish when it needs the itch "scratched." I had the good fortune to observe and film one such kelpfish in an opening in the kelp forest. Strangely, there were no senoritas in sight. I was about to see an example of "do it yourself" ingenuity. The kelpfish bent its body in a u-shape and used its tail to scratch its gill opening! It is such sightings that frequently reward me as I look for the unusual in a common species. Divers who do this often observe behaviors that are unknown to the ichthyologists stuck in their lab most of the time. Documenting the behavior with a camera or camcorder can lead to a scientific discovery that might even be publishable.

So my advice to divers and snorkelers is to buy my new DVD and use the examples on it to enhance your own experiences in the underwater world. Yes, I know... that is shameless self-promotion. But I assure you it will be an interesting show based on feedback from viewers who have already seen pre-release versions. Slowing down, focusing on the common species and watching their behavior can truly enrich your own experience underwater. I try to learn as much as I can from such observations. One lesson is that I must find a pretty senorita to scratch my itches (strictly G-rated of course) since I'm tired of using the back scratcher by myself.

© 2005 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.

(Top) Senorita cleaning parasites from gill region of giant kelpfish; (bottom) a kelpfish
"doing it yourself" by scratching its gill region with its tail.

This document maintained by Dr. Bill Bushing.
Material and images © 2005 Star Thrower Educational Multimedia