Hawaiian Trough the Hawaiian Arch. The Hawaiian Arch extends about 200 meters above the surrounding ocean floor, and contains tilted coral reefs. The coral reefs in the Hawaiian Tough are described as mesophotic coral ecosystems, which can be found between 100 and 500 feet below sea level. 43 percent of fish species documented at the mesophotic reefs are unique to the Hawaiian Islands. At Maui’s ‘Au’au channel the largest uninterrupted mesophotic coral ecosystem was discovered, with an area larger than 3 square miles. These reefs contained many stony, reef building coral that belong to the genus Leptoseris, which are adapted for deep
Hawaiian monk seal its own, and returns to the sea to forage for the first time since the pup’s arrival. Most seals are found on the Northwestern Hawaiian Islands. The Hawaiian monk seal is endangered, although its cousin species the Mediterranean monk seal ("M. monachus") is even rarer, and the Caribbean monk seal ("M. tropicalis"), last sighted in the 1950s, was officially declared extinct in June 2008. The total population of Hawaiian monk seals is in decline - the larger population that inhabits the northwest islands is declining while the smaller population on the main Hawaiian Islands is increasing. In 2010, it was