The Hawaiian Islands rise straight up off the seafloor and into the sky making vertical cliffs underwater. In Tahiti, the islands are so old they have developed barrier reefs, which give a lot of habitat to marine life.
Each species has lots of room to feed and call home, but in Hawai‘i the reefs are straight up and down, which does not give much room for fish to feed, so they had to develop new techniques on how to find food unlike their cousins on other Pacific Islands. Hawaiian fish have learned how to hunt together and use each other’s skills to their advantage, which makes our fish behaviour different than in the rest of the Pacific.
In Hawai‘i, jacks (omilu) hunt in cooperation with moray eels (puhi). Jacks will also hunt with weke, the goatfish and kaku the barracuda will hunt with the sharks. It is super fascinating to watch the fish feed on a Hawaiian reef, then go to Palau and see the very same fish species hunt in a totally different way. The most unusual hunting cooperation with fish I have ever seen is with the schools of surgeonfish hunting with nunu the trumpet fish.
Surgeonfish like the manini form large schools because they eat algae and a little fish called a gregory does not like the manini stealing their algae off the reef where they live. The gregory has become very aggressive for their 3-inch size and they will attack any manini that gets close to their home garden of algae.
Over thousands of years, the manini have learned to attract predator fish to come along with the school and eat the gregory so they could have the entire algae garden to themselves. The trumpet fish (nunu) are long and thin, so they hide right in the middle of the school of manini and when the little gregory fish comes out to chase the manini away they get eaten by the trumpet fish.
What is really amazing is the trumpet fish have developed different colors to blend in with different surgeonfish schools on different islands. Along the Kona Coast on the Hawai‘i Island the nunu are always yellow and they hunt with yellow tangs.
In Kaua‘i, the nunu are green and striped or banded and they hunt with the green and yellow manini. Also in Kaua‘i, we have yellow nunu but they hunt by themselves because there are no schools of yellow tangs to hunt with.
When you scuba dive all around the Pacific you realize how unique Hawaiian marine life is because they have adapted strategies to live that are different due to being isolated 3,000 miles out in the middle of the ocean.
You can see the trumpet fish and surgeonfish hunting together in my movie about marine life at Koloa Landing in Kaua‘i up on my YouTube page at Underwater2web.
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Terry Lilley is a marine biologist living in Hanalei Kaua‘i and co-founder of Reef Guardians Hawai‘i, a nonprofit on a mission to provide education and resources to protect the coral reef. To donate to Reef Guardians Hawai‘i go to www.reefguardianshawaii.org.
