Highest Endemism in the World Found in Hawaii Reefs

The northwestern Hawaiian island chain is home to a very special network of deep coral reefs. Those reefs are part of the Papahanaumokuakea Marine National Monument, and they contain the most abundant collection of endemic species found in any region of the world, according to NOAA scientist Randall Kosaki, PhD. This is another reason why we're proud to support the work of marine scientists through our Maui ocean tours.

   Kosaki is the deputy superintendent for Papahanaumokuakea Marine National Monument, within NOAA's Office of National Marine Sanctuaries. His study has recently been published in Marine Biodiversity, a scientific journal, revealing the complexity and abundance of deep coral reef fish communities found exclusively in Hawaii. The region contains one of the planet's richest reservoirs of biodiversity, and the highest level of endemism in any marine ecosystem recorded so far.

If you aren't familiar with the term "endemism," it simply refers to species that have developed in a certain region and exist nowhere else. These species have evolved specifically to take advantage of their ecosystem of origin, often developing unique traits in the process, which make them especially interesting to the scientific community. High endemism also tends to occur in places with conditions that are especially hospitable to life in some way. As a result, such ecosystems contain many "niches" for various species to fill, leading those species to become highly specialized for their environment. The complexity of these ecosystems can be mind boggling.

Isolation is another driver behind high endemism, and the Hawaiian archipelago is one of the most remote on Earth. You may be wondering how that can be a factor when oceans are all connected, but migration can still be dangerous, challenging, and even virtually impossible for some marine species. Consider that they're reliant on certain conditions and food availability to survive, which aren't available everywhere for some species.

The communities referenced in the study are found at a 300-foot depth near the Kure Atoll, which is 1,300 miles northwest of Honolulu. Given the very specific location of this ecosystem, you're not going to find these particular species when trying out a Molokini snorkel tour, or when you're exploring the reefs around Maui, but Hawaii's shallower waters foster a stunning biodiversity all their own. Funny enough, the reefs that lie between 150-450 feet of depth are called the coral reef twilight zone, and are some of the most poorly explored marine ecosystems. They're in that awkward area that's too deep for most scuba diving, but much shallower than submersibles are designed for.

Now, these twilight zone reefs are coming to represent a new frontier for coral reef research. Hopefully, that means we'll get to find out about a stream of discoveries in future years as these ecosystems are more thoroughly documented. In the meantime, we hope to see you aboard one of our Maui ocean cruises and tours, and if you want to learn more about these marine discoveries, you can check out the study in the Marine Biodiversity scientific journal. Mahalo!