"Coral Bleaching Event in Hawai'i"
cindyh at hawaii.edu
Fri Sep 13 23:20:36 EDT 1996
The current coral bleaching event in Hawaii is not limited to Kane'ohe
Bay. Corals in Kailua Bay, a shallow but more open-coast environment
southeast of Kane'ohe Bay on Oahu, have shown exceptional bleaching
responses over the past two weeks.
The bleaching in Kailua Bay was first evident on Labor Day weekend--just
after a period of very warm, nearly windless weather conditions.
Near-shore seawater temperature in Kailua Bay on September 2nd was 31
degrees C. Up until that time (over the past four years), we had not
measured temperatures higher than 29.5 degrees in Kailua Bay [on 9/7/95].
All coral species (large massive bommies=Porites evermanni and P. lobata;
rice and lavendar coral=Montipora verrucosa and M. flabellata; rose and
lace coral=Pocillopora meandrina, P. ligulata, and P. damicornis) were
bleached to varying extent, except the common finger coral, Porites
compressa; bleaching in this species didn't appear for another three to
four days. Of note is that colonies of Montipora patula, an encrusting
species found in the same habitat and often adjacent to bleached Montipora
verrucosa and M. flabellata, has _not_ bleached.
As of yesterday (September 12th), nearly every coral in Kailua Bay from
shore to about 1.5 km out--in depths to 5 m--appeared bleached, with most
colonies being white or very pale. In the past 10 years of our studies on
corals in Kailua Bay, we have not seen anything close to such a bleaching
response, both in terms of extent of pigment loss and numbers of species
Seawater temperatures returned to normal (about 28 degrees) rapidly
(within a week). Since we have not previously observed such an extreme
bleaching event in Hawaii, we cannot predict how long corals will take to
recover. Some mortality is already apparent in colonies of the most
rapidly bleached species-- Pocillopora damicornis and P. meandrina (lace
and rose coral).
University of Hawaii
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