Dive Dry with Dr. Bill

086: The Boxer- Banded Coral Shrimp

Yes, my mind still dwells on the warm waters of the northwest Caribbean today. Unfortunately my body is here in the cool waters of Catalina! At least our temperatures seem reasonably warm for this early in the season. When I left for Belize and Honduras in January, there were several species on my "must see" list. I hope you will bear with me as I write about a few of them before returning to the critters of our own temperate kelp forests.

For years I had seen banded coral shrimp in underwater pictures and movies, and watched them in the Indo-Pacific a few years ago. I was hopeful that I would finally have a chance to capture them on video during my trip. I was not disappointed. Several times during my dives I observed these beautiful crustaceans in action, always in pairs, in places like Coco Plum and Lime Cayes (Belize) and Utila, Honduras. They frequent coral reef areas throughout the tropics and usually live in pairs in sponges and crevices in the reef. The male is usually the smaller of the two.

The first time I was drifting slowly with the current filming an azure vase sponge. Although things look quite small through the camera's tiny viewfinder, I thought I saw several white antennae sticking out of the sponge's osculum or primary opening. I stopped and kicked back to find a pair of these shrimp living inside the sponge's central chamber. They initially retreated into the deeper recesses, then worked their way cautiously back up towards me.

I was able to film them for several minutes, giving me the opportunity to observe their behavior. The shrimp would sit just below the opening of the osculum and wave their long white antennae in the "air." These antennae are used to attract fish to their location. Why, you ask, would a small 1-2" shrimp want to attract a much larger fish which could possibly eat them? These shrimp are another example of a cleaner organism, and after attracting a fish to their cleaning station they will pick parasites and dead tissue off them.

Apparently these cleaner shrimp are specialists rather than generalists. They focus on parasites and diseased tissue located on the fish's head including the gills and mouth. If I were them, I think I'd pick a safer location like the tail, but fish being cleaned generally leave these shrimp alone. Like other cleaner organisms, they have a little bit of immunity due to the services they provide... but "accidents" do happen!

Each shrimp has two pair of the long white antennae to serve their "advertising" needs. The body and claws have a white background and are banded with red sometimes bordered with purple. Another common name for them is the barber pole shrimp, although I haven't seen any outside Lolo and Frank's shop! Due to this bright coloration they are quite obvious, making it easier for fish to find them. I wonder if they learned the value of such advertising from William Wrigley Jr. himself (am early and enthusiastic believer in such marketing strategies)?

Despite having five pair of legs to coordinate, they move quite gracefully. The middle pair known as the chelipeds is enlarged and equipped with small claws that allow them to pick off the parasites. They are called boxing shrimp because they often hold their claws up like a prize fighter. Occasionally one of these claws breaks off, but the shrimp eventually regenerates the missing body part. We should be so lucky. Modern medical technology needs to catch up with these lowly invertebrates.

Unfortunately the beautiful appearance of these shrimp make then popular for home aquariums. It is reported that many of them die in the first day or so in a new tank. When kept there, these shrimp do not tolerate other members of their species (well, except their mate). In fact they will tear one another apart if one invades another's space. They are territorial in the wild as well, but have more space to spread out. Fortunately mates are usually cooperative and will share food.

They do elaborate courtship dances prior to mating, something human males generally do only in the early stages of courtship (if at all!). Noted marine author Helmut Debelius describes the dance this way. The two shrimp face one another with their claws spread wide. The male begins to sway side to side, then increases his tempo and dances back and forth sideways. Eventually the female responds by moving her claws and the two continue their passionate tango until mating occurs.

Banded coral shrimp sex doesn't sound too exciting. The male climbs on the female's back and transfers a packet of sperm to a pouch on her side. She then releases the sperm once the greenish eggs are laid and attached to her lower abdomen. Here they will hatch and the young "shrimps" will cling to the female for as long as six weeks. After this, they rise into the water column and drift as plankton before settling in a new area. Of course these tropical species don't drift as far as Catalina since kelp forests are too cold for their tastes. Hmmm... I could acquire such tastes myself.

© 2004 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.

Pair of banded coral shrimp in vase sponge, Lime Caye, Belize

This document maintained by Dr. Bill Bushing.
Material © 2004 Star Thrower Educational Multimedia