Monday, November 9, 2015

Bye Bye Big Mama

By Darla White

I just wanted to share some observations about the bleaching event at Olowalu, especially one colony that we have been calling 'big mama'. This colony is 8.3 meters in total diameter (27' edge to edge).  It has lost more than 90% of its live tissue in the last two months due to the bleaching event. What polyps that are still there are still bleached and sickly looking.  

'Big Mama,' a large colony of Porites lobata (lobe coral) found at Olowalu in West Maui, that has suffered significant mortality (death of the living coral tissue) due to the ongoing global coral bleaching event. Photo by Darla White.
Olowalu was hit very hard. The sediment in most areas we observed is settling thickly in the algae that has newly overgrown parts or all of colonies, with little hope for recovery in the near term. One Scripps Institution of Oceanography mosaic site did not appear to have a sedimentation issue and had plenty of Crustose Coralline Algae (CCA), so time will tell but it likely has a better chance for resilience. Both the NOAA bleaching survey folks and the XL Catlin Seaview Survey team commented on Olowalu and how bad it was this past week, with some areas still exhibiting 50% bleaching. The newly dead colonies have a thick covering of limu (algae), but you can still feel and even see the newly dead corals underneath the fuzz mats. I wish we had been able to finish the baseline survey in the shallows at Olowalu before the bleaching event. Alas, all we have is the aftermath. The Porites spp. were hit the hardest.

There is still active bleaching, but definitely active recovery, too. Corals are regaining their color in part, many from the base upward or on the sides, with the worst affected areas mostly on the upward facing surfaces. New algal growth by-in-large dominated on the upward facing surfaces of most colonies observed, especially Pocillopora.  

Some color morphs did really well and were mostly resistant to the bleaching, including the rust-colored Montipora patula, and both the mustard and taupe color morphs of Porites lobata, and the taupe P. compressa.

Darla J White
Special Projects Coordinator
Hawai'i DLNR Division of Aquatic Resources, Maui
130 Mahalani Street, Wailuku HI 96793

Eyes of the Reef
Island Coordinator, Maui


Darla White on a recent survey of coral bleaching at Molokini crater, Maui. Photo by Liz Foote.

No comments: