Moorea: The Coral Reef Community

From the researcher's perspective...

Gobies are among the most diverse group of fishes. They include the smallest species of known fish, bizarre forms like the mudskippers, and are the largest group of marine species of any family of fish. That said, they have a distinctive look - sometimes they appear to be "all head". It is a diverse, impressive group that has evolved to live in all sorts of strange places—like in the branches of coral!

The Paragobiodon species are parasites of coral. They live on it, lay their eggs on the underside of its branches, and eat it. No one knows very much about them because they are never seen outside of their coral hosts. They are what we call an "obligate" symbiont—this fish is only found in a particular species of coral. That level of intimacy between two different species has costs and benefits. The goby gain a precise ability to use the Pocillopora corals as a source of energy and shelter, but if a goby finds itself on a reef without Pocillopora, it is out of luck. This is a pattern seen over and over again in coral symbionts—many are specialists limited to a very narrow range of hosts. This "fine tuning" of the relationships between the organisms on the reef is part of what allows for such tremendous biodiversity.

Chris Meyer, Seabird McKeon, Hannah Stewart, and Matthew Johnson