Why such a high percentage of endemic species in Hawaii

The location of the Hawaiian Islands is in the Central Pacific Ocean, on the northern most edge of the tropical zone.  The eight main islands, Ni’ihau, Kaua’i, O’ahu, Moloka’i, Lana’i, Kaho’olawe, Maui, and Hawai’i (the Big Island) are most commonly known as “Hawaii” and contain 99 percent of the land area of the islands, however the Hawaiian chain of islands really begins with the Emperor Chain of seamounts stretching about 3700 miles to the northwest of the Big Island.

3IslandChain

The Hawaiian Chain of islands are isolated by a gap of over 1000 miles from the nearest island groups to the south and west.  This gap has prevented a large number of species from migrating here.  Most marine animals begin life as minute drifting larvae, known as plankton.  These plankton are carried by ocean currents, until they eventually settle to the ocean floor.  Many forms of plankton do not survive in the larval stages long enough to make the 1000 mile journey and thus have not established themselves here.  Once a larval stage plankton arrived in the islands, the struggle was not yet complete.  A suitable habitat had to be found with an adequate food supply and sufficient numbers of both male and female of the species had to make the same journey and end up in the same place for the species to establish itself in these isolated islands.  Due to the difficulty of this process, fewer marine species occur in Hawaii than in other areas of the Indo-Pacific area.  While this isolation has reduced the number of species significantly, it has also made possible the emergence of many new species found nowhere else in the world.

This occurrence of unique species in a small area are known as endemic species.  It is on these species that we will focus during our dives.  You will see both vertebrate and invertebrate species that are totally unique in size, shape, coloration and behavior.

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