STEM Logo

Dive Dry with Dr. Bill

#698: Clean Up Your Act [Cleaning Behavior]

No, this column won't be about the judge that counseled me when I was a bad boy. Why, that never happened. Dr. Bill was always a fine, upstanding young man who never got into trouble... or at least never got caught! It could apply to the state of my home though... but divebums are too cheap to hire someone to clean for them, and too busy editing the day's underwater video to do it themselves!

Today I'm going to blab on about how some of our marine critters take care of certain cleaning needs. Obviously they don't grab a broom and dustpan, or a mop or a vacuum or a dustcloth. It may be filthy down under, but no one takes responsibility for that except the sea cucumbers and other detritus feeders. I'm talking about cleaning up something completely different.

Fish (and other critters) often acquire loads of parasites, bacteria and dead tissue. Without arms and hands, it is very difficult for them to remove these. I have seen fish rubbing themselves on the rocky reef and even giant kelpfish scratching their itches with their tail. Dogs and cats can "con" their humans into combing off the fleas and picking off the ticks, but I won't do that for my fine finned friends. Fortunately there are others who often specialize in picking tidbits of off hosts. They are known as cleaners.

In the tropics such activity usually occurs at fixed cleaning stations. Fish ranging in size from fairly tiny to huge manta rays may line up to wait their turn at such a spot on the reef. Here in our temperate waters, cleaning activity more often occurs in random places. The cleaners generally come to the hosts and perform that duty wherever they meet.

On a recent dive I observed and filmed quite a bit of cleaning behavior in our dive park. This behavior is often referred to as symbiosis, a type of "mutualism" where both species benefit from their interaction. The host gets rid of irritating parasites, potentially harmful bacteria and diseased tissue. The cleaner gets a tasty tidbit to nourish itself.

Some species like blacksmith (Chromis punctipinnis) and halfmoon (Medialuna californiensis) will gather together and actively solicit cleaning by fish such as señoritas (Oxyjulis californica) or rock wrasse (Halichoeres semicinctus). It is not unusual to see a big ball of blacksmith clustering together in midwater to try to get a lovely señorita to pick them clean. Halfmoon tend to cluster near the bottom and attract rock wrasses to clean them.

Many of my readers are aware of the cleaning relationship between the red rock or California cleaner shrimp (Lysmata californica) and the California moray (Gymnothorax mordax). The shrimp often gather in a moray's hole and crawl all over the moray picking off delicious copepod parasites, often grabbing them with their claws and crushing them before swallowing. They may walk right into the moray's mouth to clean the teeth... but better be careful as the moray has notoriously bad eyesight and occasionally will munch them.

One of the more interesting examples of cleaning symbiosis in our waters is that involving the giant sea bass (Stereolepis gigas). Those of you who have seen them underwater or looked at pictures of their heads, know that they are infested with loads of copepod parasites that make them look like I did after my surgery... badly in need of a shave. The whiskers on them are actually the egg sacs of the female parasites.

Now what makes cleaning a giant sea bass interesting is the element of danger involved. I've observed señorita, rock wrasse, sheephead and kelp bass (Paralabrax clathratus) perform the function. Few of them will clean the head... for a very simple reason. Giant sea bass are suction feeders able to suck up lobsters and other critters by expanding their huge mouths. A good cleaner wants to gain a meal, not become one! I did film one kelp bass that attacked parasites on a GSB's head by coming in from above and behind, then literally bouncing off the GSB! Smart move. Must have been a gymnast.

© 2016 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. You can also watch these episodes in iPod format on YouTube through my channel there (drbillbushing). Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

To return to the list of ALL of Dr. Bill's "Dive Dry" newspaper columns, click here.


Rock wrasse cleaning halfmoon and señorita mobbed by blacksmith; living dangerously; cleaner shrimp
and moray and kelp bass (arrow) bouncing off giant sea bass' head after taking a parasite.

This document maintained by Dr. Bill Bushing.
Material and images © 2016 Star Thrower Educational Multimedia