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Pacific Ocean (east) Bleaching was first noticed in the Pacific when the 1997 El Nino event resulted in warm water pooling up in the mid to eastern tropical Pacific along the coastline of Central America. Water temperatures of 27-28oC were recorded from June to October 1997 off Panama and coasts further north, which are 8oC warmer than normal. As this pool of warm water expanded, it then affected the Galapagos islands (on the Equator) in December to February, when surface waters were up to 3oC warmer that normal. Bleaching of the corals started at the extreme temperatures around 30oC. Colombia (Pacific Coast) The first signs of bleaching were in late-May 1997 with small white patches on Pocillopora when water temperatures were 29oC. More bleaching was observed in July and August 1997 with increased signs of bleaching at similar temperatures. In September 1997, up to 30% of some Pocillopora was bleached, whereas similar corals nearby appeared normal. (Fernando Zapata) Galapagos The first bleaching reports were in mid-December 1997, when water temperatures of 28oC were recorded from satellites. Water was 2oC warmer in February and bleaching continued. Nearly all corals on the Galapagos were bleached to some extent by March 1998. The most strongly affected were Porites and Pavona. The genera Psammocora, Diaseris and Cycloseris were bleached on top, but many still had pigment around the bases. Corals bleached down to 30m, but bleaching was more extensive shallower than 10 to 15 m depth. Pocillopora, which was most impacted during the big El Nino of 1982-83, seems to be largely resisting this time. (Andrew Baker, Joshua Feingold, Jerry Wellington, Al Strong) Mexico (Pacific Coast) Bleaching was first noticed in July 1997 from the Gulf of California (25oN) to Jalisco (19oN) and in the remote Revillagigedo Islands (18oN). Bleaching peaked in August-September 1997 involving about 25% of total coral cover (water temperatures were 31-34oC). The most extensive bleaching occurred at Nayarit (20oN), of about 60% of corals mostly shallower than 4 m. Bleaching was 10-15% in the Revillagigedos, with some mortality, but had finished in October. The only significant recovery in the Gulf is from new Pocillopora recruits settling on the old skeletons. This the first time that bleaching has been reported on the Pacific coast. Very minor bleaching was seen at Oaxaca (16oN) in 1997 with water temperatures at 31oC; all colonies recovered. A sudden drop in surface water temperatures in mid-September 1998 caused extensive bleaching and this is being followed. No bleaching or death was observed on Clipperton Atoll in November 1997. (Gerardo Leyte-Morales, Hector Reyes) Panama (Pacific Coast) There was significant coral bleaching in mid-September 1997 at Uva Island, Gulf of Chiriqui. All coral species were affected down to 20 m. Millepora intricata, the most common species remaining after the 1982-1983 El Nino, bleached and died. Other species were still alive but bleached. Almost all coral species in the Gulf of Chiriqui region started bleaching in mid-April 1998 with 50% to almost 90% of corals with at least partial bleaching. This follows the bleaching above, but is much less intense than in 1983. Bleaching occurred when water temperatures were 29-31oC, more than 1.5oC above normal. Corals from nearby Gulf of Panama showed much less bleaching. (Andrew Baker, Mark Eakin, Peter Glynn and Juan Maté )
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