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Tangs versus algae

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Fish | Sharks

Friday, April 04, 2008

David

Shark Lagoon is an outdoor exhibit which means it is fully illuminated by the sun. Photosynthetic organisms, such as algae, thrive in environments where they can get plenty of sunshine. This is unfortunate because if left undisturbed, the algae can quickly blanket Shark Lagoon and leave it looking dirty. This is where the tangs come to the rescue. No, I am not talking about a powdered drink. I’m talking about a family of colorful fish that are great at controlling algae.

Tangs are herbivores and they love algae. In their natural environment, they help the coral reef by keeping algae at bay and reduce stress on the coral. Thus, it was only natural to utilize the tangs’ innate ability to control algae at Shark Lagoon. The alternative solution was to manually scrub the walls of the exhibit. Who wants to do that (OK, so we still have to do that, just not as often!)? Besides, the tangs add tons of movement, color and life to Shark Lagoon.

There are over five species of tangs at Shark Lagoon. The powder blue tang, Acanthurus leucosternon, is one of my favorites. It has a bright yellow dorsal fin, a black mask over its face and a beautiful shade of baby blue all over its body. The powder blue tang has a pretty aggressive demeanor but considering that it is living with sharks, that may not be a bad thing. Other tangs in the exhibit are the naso tangs Naso literatus, palette tangs Paracanthurus hepatus, yellow tangs Zebrasoma flavescens, and sailfin tangs Zebrasoma desjardinii.

The reason why it is a bad idea to touch these fish is twofold. First of all, they have sensitive skin with a thin mucous layer. Too much rough handling can damage their skin which can lead to infection and disease. Second, all tangs (also known as “surgeon fish”, and you will see why) have small blades at the base of their tail which they use for protection (we call them scalpels). A tang can use these blades to inflict damage on predators or anything that may cause them harm. Therefore, it is best to leave the tangs alone, let them do their job and just enjoy having them in Shark Lagoon.

Tangs versus algae
A sailfin tang hangs out with green scats  | © David Chen
Tangs versus algae
Look at the base of the naso tang's tail. You can clearly see the 4 orange-colored blades it uses for protection.  | © David Chen

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marinedepot

Tuesday, April 08, 2008 02:46 PM

So the tangs are permanent residents in the shark lagoon now, or just until the algae issue is under control?

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David

Tuesday, April 08, 2008 06:57 PM

Algae never stops growing. Therefore the tangs’ job is never done.
Nutrient rich water fuels algae growth. We have mangrove trees in Shark Lagoon to keep phosphates and other nutrients under control but so far it does not help. Sharks are messy animals whose protein rich diet keeps the water pretty nutrient dense.
In short, the tangs are permanent residents of Shark Lagoon.

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Jason

Friday, April 25, 2008 12:58 PM

Actually, David, I’ve got a question.  Can you do a post describing how the Aquarium gets and disposes of its seawater?  Is this information available online already?  Just curious if its being drawn directly out of the harbor and recycled back in.  Thanks, Jason

David's avatar

David

Friday, April 25, 2008 11:51 PM

Thanks for the question, Jason. Unfortunately, I am not an expert on this subject but I can tell you that we do not get our water from the harbor. Nor do we make our water from synthetic salt. A truck brings water, which was collected from a clean source, to the Aquarium. Staci, another fellow blogger, has agreed to write more about this subject so be on the lookout for her blog entry.

All blogs and comments represent the views of the individual authors and not necessarily those of the Aquarium.

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