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Observations made on coral reefs on the Big Island:
On 3/10/96 Brian Tissot (Tissot@Hawaii.edu) wrote:
District: Kohala; Reef: Pelakane Bay
Observation: effects of last weeks storm were visable by the high amount of sediments in the bay. Visability in some areas was less than 10 cm. Many coral colonies were lightly covered with silt due to land runoff. This area receives abnormally high sedimentation due to deforestation and cattle grazing upslope.
On 10/02/96 Brian Tissot (Tissot@Hawaii.edu) wrote:
District: Kona; Reef: Honaunau
Observation: Stu Meriweather & Sara Peck (Kona Sea Grant Agent) took me diving north of the boat ramp at Honaunau to examine some broken coral areas. I saw six huge areas of broken coral which appeared to be human in origin. Each broken swath was about 6 m wide and extended from near, but not at, the top of the reef slope (about 10 m depth), down to about 20-25 m; close, but not at, the bottom of the reef slope. There were no large piles of coral at the bottom of these swaths which you might expect if debris has rolled down the steep slope (about 30-40 degree). Within this area, finger coral (Porites compressa) was completely destroyed, and was being covered by a black fungal mat ( up to 1 cm thick!) on month old areas, and red seaweeds (mainly Galaxaura fastigiata) on 6 month to 1 year old patches. The coral Pavona varians also appeared to be colonizing and growing on the dead finger coral. Stu provided approximate dates based on his diving observations.
The causes of this damage is unknown, but it is clearly not natural in origin. Any ideas?
On 10/26/96 Brian Tissot (Tissot@Hawaii.edu) wrote:
District: Kohala; Reef: Puako
Observation: While diving at Puako, off of the Church access, Leon Hallacher, John Coney and I noticed quite a bit of bleached cauliflower coral (Pocillopora meandrina), mostly at 40 to 10 foot depths. Our estimate is that as much as 50% of this species exhibited bleaching. The colonies were generally bleached almost to their bases (about 50-75% of their total area). I noticed that the polyps were still visable and appeared healthy on bleached corals. I did not notice any other species exhibiting bleaching. Leon said he first saw bleaching the week before (10/19) but neither of us has been at Puako since May.
I wonder if this is related to the late Aug.-early Sept. bleaching episode noticed on Oahu in Kaneohe Bay? That episode appeared to be associated with a few weeks of abnormally warm weather.
On 11/17/96 Brian Tissot (Tissot@Hawaii.edu) wrote:
District: Hilo; Reef: Keaukaha District
Observation: Due to an unusually large winter storm we had 10-15 foot waves from a NE direction on our coastline for 2-3 days. Many people stated this was the largest surf in 40 years! Many coastal roads were closed as waves threw boulders up on the road and moved one oceanfront house. After the storm many reefs had drastically changed. Based on observations of several university students coral in 0-30 foot depths was completely cleared at Chocks and Leilewi Point. Coral cover from earlier surveys had 30-60% cover at these locations. My observations at Onekahakaha Beach Park (which is a protected area) is that the bottom was almost completely cleared of all fleshy algae (mostly Padina & Gracilaria), probably due to scour and rolling boulders. Macro-invertebrates seem to be similar to pre-storm levels but coral seems much lower in abundance. It will be interesting to watch the recovery!
On 11/24/96 Brian Tissot (Tissot@Hawaii.edu) wrote:
District: Kohala; Reef: Puako
Observation: Revisited Puako, off of the Church access, to reassess the coral bleaching observed earlier (see above). Some was still present although greatly reduced. Cauliflower coral (Pocillopora meandrina), mostly at 40 to 10 foot depths, still displayed some bleaching. My estimate is that about 10-20% of this species exhibited bleaching. The colonies were generally bleached only at their tips (about 5-20% of their total area). Many of the polyps at the tips were dead but the coral colony appeared healthy and alive. One anecdotal observation is that the colonies exhbiting bleaching appeared darker (more zooxanthellae?) than other colonies. Interesting......!
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