UNIHI-SEAGRANT-TT-14-01 Republic of the Marshall Islands Coral Bleaching Report By Karl Fellenius, University of Hawai’i Sea Grant - Coastal Management Extension In association with Jesse Capelle, Candice Guavis, Lyla Lemari, and Benedict Yamamoto Marshall Islands Marine Resources Authority (MIMRA) Produced for Marshall Islands Coastal Management Advisory Council (CMAC) and NOAA Coral Watch Dec 31, 2014 *Additional photographic documentation provided by Remi Chauvin and Karl Mathiesen, journalists with the Guardian newspaper in London. Their article can be found at http://www.theguardian.com/environment/2014/dec/19/major-coral-bleaching-pacific-may-worst-20-years Note: Example low resolution photos are included with this report. All high resolution photos are available on dropbox. Invite requests can be sent to [email protected] Table of Contents 1. General Synopsis 2. Sea Surface Temperatures & Records from PacIOOS-CDIP 3. Observations – Sept through Nov Bleaching Times & Locations 4. Observations – December Monitoring Locations 1. General Synopsis The worst coral bleaching event ever recorded for the Marshall Islands has been occurring since about mid-September. Sea surface temperatures have been high since July. Thermal stress has been dropping off slowly since the third week of November. The event saw the highest bleaching impacts from mid-September through October, with evidence of bleaching as recent as mid-December. This has very significant consequences for coral reef health, food security, and coastal protection. This report serves multiple purposes: -The scale of the observations and locations may allow NOAA Coral Watch to calibrate/validate their 5km thermal stress monitoring products. -It underscores the importance of herbivores in maintaining clean surfaces for coral recruitment. This may lead to a greater emphasis on limiting fishing of herbivores before, during, and after an event. -Photos may be used by others to further identify species resistant and vulnerable to certain bleaching thresholds, given the range of growth forms and depth considerations observed. -Rationale for obtaining dedicated funding in coral reef monitoring programs to rapidly respond to events as they occur. More comprehensive monitoring is needed, and sites need to be revisited to assess whether assumptions made about adequate herbivore grazing vs. collapse of algae-covered skeletal structures are correct. This can also inform whether later stage bleaching under lower thermal stress than what was observed at the onset is low enough to allow for repopulation of zooxanthellae in some cases. On average three-quarters of all shallow digitate corals are dead, two-thirds of all table corals, half of all submassives other than Porites rus, and maybe one-quarter of all massive and encrusting corals. Limited observations have been recorded for the atolls of Majuro, Arno, Kwajalein, and Namdrik. It is likely to have affected other atolls as well, but there is insufficient capacity to monitor the full extent of bleaching in part due to the remote character of outer islands in the RMI. Therefore, the above estimates should be considered tentative, and only based on the sites surveyed. Note that most observations are for Majuro, which is already highly impacted by other stressors, and may be less able for that reason to handle the cumulative effects imposed by additional thermal stress. The event is likely severe because not only is there mortality down to 140ft., there are few white patches compared with the vast number of colonies that are completely covered over with algae. This suggests that bleached colonies likely died very quickly after the onset of high thermal stress. Note that this point is based on observations in Majuro, which has a longer timeline (Sept-Dec) than point in time reports from the other atolls. However, recent observations on Arno atoll show a disproportionate number of white colonies alongside algae-covered colonies compared with earlier observations in Majuro. It is unlikely that this amount of bleaching is happening every few days because temperatures are lower now than they were in September-October. This suggests that a lower thermal stress is still causing coral to bleach, and that some colonies are hanging on for a period of time before succumbing. The good news is that the common Majuro coral, Porites rus is doing well and is largely unbleached. This submassive species has generally taken over Majuro lagoon in recent decades as it is more resistant to pollution than other species. However, it is also known to not significantly support fisheries habitat as well as other species that have bleached. Another species that appears to be resistant with the exception of a few cases is Porites cylindrica. No cases of bleached Heliopora coerulea were observed. For the most part, deeper and massive growth forms of Porites sp. are doing o.k. Shallow submassive and branching Montipora sp. appear to be resistant as well, although related encrusting forms of Porites sp. and Montipora sp. are affected. Acropora sp., Isopora sp., Pachyseris sp., Pocillopora sp., Favia sp., Pavona sp., Astreopora sp., Stylophora sp., Goniastrea sp., and Herpolitha sp. make up the majority of the bleached genus. Please note that the detailed observations below do not attempt to do extensive species and genus ID, as we expect others more qualified in this respect to look at the individual photos on dropbox. Nov 7, 2014 Correspondence from NOAA Coral Watch: “NOAA Coral Reef Watch had issued a Bleaching Watch for the Virtual Stations at Majuro, Namdrik, Enewetak, and Ailuk Atolls, based on increasing levels of thermal stress in the Marshall Islands, as monitored by our satellite-based 50-km products over the last few months. We did note that sea surface temperatures (SST) had exceeded and held steadily above the maximum monthly mean SST since July 2014. Our daily 5-km products (http://coralreefwatch.noaa.gov/satellite/bleaching5km/index.php) also monitored prolonged, elevated levels of thermal stress, and our Seasonal Coral Bleaching Thermal Stress Outlook (http://coralreefwatch.noaa.gov/satellite/bleachingoutlook_cfs/outlook_cfs.php) has been predicting that the thermal stress would remain in the Marshall Islands and potentially even elevate to a Bleaching Warning by mid-November 2014. However, we did not know until yesterday (ed. initial notice from RMI) that the extent of bleaching was so severe already!” Nov 9, 2014 Correspondence from Dr. Thomas Goreau re the Goreau-Hayes HotSpot method: “I developed the method for predicting bleaching from satellite SST data, put together long term databases for RMI, and predicted this event in advance. NOAA uses my HotSpot method in making their predictions.” 1. Sea Surface Temperatures & Records from PacIOOS-CDIP Local records of SSTs around Majuro are compared below for July through December 2010 and 2014 from the PacIOOS Kalo Waverider Buoy on the oceanside at Delap Point (in blue). (source: http://cdip.ucsd.edu) Local records of SSTs around Majuro are also compared below for July through November 2010 and 2014 from the PacIOOS water quality sensor on the lagoon side at Uliga Dock (in red). (source: www.pacioos.org) * note that the scale does not match up exactly. Others are better positioned to assess how much can be inferred from a comparison between 2010 and 2014 with respect to average temperatures across a longer timeframe. But what appears to be the case is that warming has greater variation on the oceanside than on the lagoon side. Note that lagoon side temperatures are stabilizing to lower values since about the third week of November, but that the oceanside took until late December to return to the values seen for the same period in 2010. This may explain the mid-December observations of oceanside bleaching at Arrak on Majuro and near the village of Arno Arno on Arno atoll. While the temperature data for the lagoon side for December is not graphed yet, it dropped to 28.8 C on Dec 24th. 2. Observations – Sept through Nov Bleaching Times & Locations Mid to end of September -Lagoon side bleaching off Rong Rong & Bikirin Islands, NW Majuro atoll was anecdotally reported at the end of October to have occurred mid to end of September. No growth form or genus info., photos, depth, or percent estimates. Mid-October -Oceanside bleaching at Arno Arno, in W Arno atoll was reported by MIMRA during the third week of October to have occurred mid-October. White submassive and massive coral colonies along with at least one anemone photographed at 20 ft. No percent estimates. -Oceanside bleaching at Delap Point, SE Majuro atoll was reported by MIMRA during the third week of October to have occurred mid-October. White encrusting and Acropora sp. table and branching colonies photographed. No depth or percent estimates. -Lagoon side bleaching in the Woja MPA, Long Island, SW Majuro atoll was anecdotally reported by local landowners during the third week of October, thought to have occurred mid- October. No growth form or genus info., photos, depth, or percent estimates. -Lagoon side bleaching in Rairok, central Long island, S Majuro atoll was anecdotally reported by local residents during the third week of October, thought to have occurred mid-October. No growth form or genus info., photos, depth, or percent estimates. Anemones also noted as bleached. Third week of October -Oceanside bleaching along the eastern end of Long Island, S Majuro atoll was reported by College of the Marshall Islands (CMI) Marine Science Instructor, Steve Why to be ongoing. This was the first report of bleaching, which triggered others to report in and for MIMRA, CMI, and UH Sea Grant to begin organizing for formal monitoring. On Oct 24th UH Sea Grant’s Karl Fellenius collected preliminary info. via an intertidal walk and photographs at the old excavation pits and reef flat on Long Island adjacent to the bridge. There was complete bleaching of all reef flat Acropora sp.