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 theGuardian 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 karl.fellenius@hawaii.edu

Table of Contents 1. General Synopsis2. Sea Surface Temperatures & Records from PacIOOS-CDIP3. Observations – Sept through Nov Bleaching Times & Locations4. Observations – December Monitoring Locations

UNIHI-SEAGRANT-TT-14-01

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. digitate colonies. 90% of these were white or pale and had just died or were on the verge of dying. 10% of them had died within a few days as there was some evidence of the initial stages of filamentous algae growth. Encrusting bases of these Acropora sp. digitate colonies were also bleached. No other coral except for the only two Acropora sp. table corals in the area, which were similarly bleached. The majority of the reef flat along this part of Long Island and Delap’s south shore is covered in invasive Hypnea sp. algae related to inadequate sewage discharge infrastructure, so the area is already severely stressed.

*high swell and wind combined with booking issues for a survey boat prevented monitoring sites further afield during most of the month of November.

-Oceanside bleaching obvious from photo taken by Dennis Hwang of UH Sea Grant on the flight approach W of the airport on Long Island, S Majuro atoll on Nov 19th. This is consistent with various anecdotal reports from others since the third week of October that white patches could be seen down the drop-off from the surface on calm days by people walking around at low tide.

Mid to Late October -Oceanside bleaching East of Kwajalein Lodge and North of Roi-Namur in Kwajalein atoll was reported by Curt Storlazzi, USGS Pacific Coastal and Marine Science Center in early December, to have occurred mid to late October. No growth form or genus info., or percent estimates. Depths of bleaching reported from 30-80ft., although none observed in the shallows.

Late October/Early November -Lagoon side bleaching on 3 patch reefs close to the Pearl house in Namdrik atoll was reported by Paul Mandala, a World Teach volunteer during the third week of December, thought to have occurred late October/Early November. No growth form or genus info., photos, depth, or percent estimates. However, there is some video footage available that was taken near the uninhabited island of MarMar. This area had some of the thicker algal mats observed, with some limited bleaching evidenced by white patches. Significant funnelweed (Padina sp.) also reported throughout the lagoon.

First or second week of October through at least end of November -Lagoon side bleaching at the Lojemwa dredge/coral relocation site 3mi.(5km) west of the airport runway, Long Island, S Majuro atoll was reported by UH Sea Grant and MIMRA to be ongoing. All photos and observations are from between 10 and 25ft. This is a site in proximity to an active dredging operation, and significant coral relocation efforts took place here starting early September. In hindsight, this work might not have been carried out if there had been earlier warning of possible bleaching. In retrospect though, at least one relocated species appears to be resistant (P. cylindrica) along with the omnipresent Majuro coral, P. rus.

Most of the dead colonies were covered in deep green and black algae, indicating that bleaching mortality is at least 1 month old, possibly up to 7 weeks old. This is corroborated by an earlier visit to the same site on Oct 2nd when no bleaching or new dead colonies were observed. Algae-covered colonies were mainly large Acropora sp. table corals (both relocated and existing), Acropora digitefera, plus a variety of encrusting and submassive forms. There were no living colonies of these varieties left. A few A. digitifera, branching Acropora sp., and massive Porites sp. colonies were observed to be white on Nov 28th suggesting that bleaching was still ongoing at that time. At least three densely-branched/submassive species (Acropora & non-Acropora sp.) were only partially affected.

3. Observations – December Monitoring The following items refer to specific dates of monitoring different sites, rather than the above which attempted to describe when the bleaching took place. Spot check and manta tow monitoring by UH Sea Grant and MIMRA took place on one day only, Dec 2nd.

Spot Check Dec 2nd Lagoon side patch reef at Marker 8, N Majuro Lagoon side bleaching observed from the top of the reef at 15ft. down to at least 140ft. There are both white patches and algae-covered colonies present. If the thermal stress was not severe this might suggest that some colonies have remained bleached but not died, and that there is the possibility of repopulation with zooxanthellae. More likely though, is that there was severe thermal stress and ensuing death of the colonies now covered in algae. Because SSTs were already dropping by this time, the thermal stress may be causing corals to bleach, but not die. This is optimistic though, as the white patches of coral may be very recent and may very well succumb in short order.

Shallow depths have less bleaching, largely influenced by the high abundance of the relatively more resistant P. cylindrica and P. rus species. Beyond 75ft. there is about 25% cover of encrusting and foliose growth forms, and almost three-quarters of these corals are bleached. Examples of bleached genus and species with depth: 100 feet Astreopora sp., Acropora nasuta 80 feet Pachyseris foliosa, Porites rus, Fungia concinna, Pavona cactus 70 feet Porites rus, Porites antennuata, Pavona cactus, Acropora nasuta 60 feet Fungia concinna, Pavona cactus 50 feet Acropora nasuta 40 feet Acropora sp., Herpolitha limax, Porites latistella, Favia favus

Spot Check & Manta Tow Dec 2nd east side of Calalin Pass, N Majuro East Calalin Pass bleaching observed on spot check from the top of the reef slope at 30 ft. down to where the it meets the sand/rubble bottom at 130ft. There are both white patches and algae-covered colonies present.

The most severe bleaching is from 50 to 70ft., with three-quarters of the roughly 40% coral cover affected. The vast majority are submassive growth forms. Less bleaching is seen both deeper and shallower. One-quarter of massive and encrusting corals are bleached from 70 to 130ft, and one-third of all table, branching, and digitate corals bleached from 30 to 50ft. Examples of bleached genus and species with depth:

80 feet Lobophytum sp., Astreopora gracilis 70 feet Astreopora gracilis, Stylophora pistillata, Goniastrea retiformis 60 feet Porites sp., Stylophora pistillata, Pocillopora verrucosa 50 feet Acropora cytherea, 40 feet Acropora sp., Acropora cytherea 30 feet Acropora sp., Acropora verweyi

Southeast Calalin Pass bleaching observed on manta tow heading N-NW from point 81 at a depth of 15-30ft. All branching colonies are at least 50% bleached, and about half of all table and digitate corals are either bleached or have recently died. Submassive corals are generally made up of P. rus with only minor incidence of bleaching.

The manta tow board is outfitted with a Go Pro camera that allowed for continuous footage during the 2 minute tow. The image that follows is a stitch of dozens of images taken from the video during the roughly SE to NW transect along the top of the reef slope at a depth of 30ft.

Manta Tow Dec 2nd Lagoon side Calalin Island, N Majuro Lagoon side Calalin Island bleaching observed on five 2 min. manta tows at a depth of 5-20ft.

West End Tows 75-76, 77-78, and 79-80 Three-quarters of all table, digitate, and submassives (other than P. rus) are algae-covered. Branching growth forms are more recently bleached and are approaching 50% mortality. Massive varieties and P. cylindrica have only minor bleaching.

East End Tows 70-71 and 72-73 Slightly worse condition than the west end tows. All table, digitate, and submassives (other than P. rus) are algae-covered. Branching growth forms are more recently bleached and are approaching complete mortality as well. Massive varieties have only minor bleaching.

Manta Tow Dec 2nd Lagoon side Eneko Island, N Majuro Lagoon side Eneko and adjacent islands bleaching observed on six 2 min. manta tows at a depth of 5-20ft.

West End (Eneko Island) Tows 85-86, 87-88, 89-90, and 91-92 East End Tows (adjacent islands) 93-94 and 95-96 All tows in this area yielded similar results. Only about 40% all table, digitate, massive, and submassive (other than P. rus) varieties are bleached or algae-covered. Algae cover on this transect is also estimated at approximately 40%. There are more unbleached table and digitate corals here compared with Calalin, but massive coral mortality is greater.

Manta Tow Dec 2nd Lagoon side Enemanit Island, N Majuro Lagoon side Enemanit Island bleaching observed on six 2 min. manta tows at depths of 10-20ft.

West End Tows 97-98, 99-100, and 101-102 Two-thirds of all table, digitate, and submassives (other than P. rus) are either bleached or algae-covered. Massive varieties show minor bleaching with the exception of a few colonies that are almost entirely bleached.

East End Tows 103-104, 105-106, and 107-108 All table corals and over half of all digitate and submassives (other than P. rus) are either bleached or algae-covered. Total mortality from bleaching is less than the amount observed on the inside of Calalin Island, but slightly greater than at Eneko. It should be noted though, that massive growth forms at both Enemanit and Calalin appear to be handling the thermal stress much better than at Eneko.

Snorkel Dec 7th & 28th Lagoon side Delap Beach to Marshall Islands Resort, Majuro Lagoon side bleaching from Delap Beach to the Marshall Islands Resort, Majuro was observed by UH Sea Grant to be occurring on Dec 7th but not on Dec 28th. About three-quarters of all table and digitate corals, and one-quarter of all massives from 5-20ft. are algae-covered. On the earlier date it was obvious that bleaching had started here quite some time ago because many of the table corals had thick black mats of algae on them. A number of the larger tables had collapsed under this weight, breaking the skeleton off at the base. One strategy employed to limit this is to break off as much as possible around the edges. Out of six anemones found all are bleached. This particular reef tract is one of the last remaining and accessible snorkeling areas in downtown Majuro. No photos taken.

Snorkel Dec 14th Oceanside Arrak, SW Majuro Oceanside bleaching at Arrak, Long Island, SW Majuro was observed by UH Sea Grant and journalists from the Guardian newspaper in London to be occurring Dec 14th. Significant algal growth on dead coral colonies suggests that the event started occurring quite some time ago.

Bleached coral was observed from the reef flat down to at least 100 ft. It is likely that bleaching continued deeper, but the divers could only see about 50 ft. below their maximum snorkel depth of 50ft. All branching coral, three-quarters of all digitate coral, two-thirds of all table coral, half of all submassive coral, and one-quarter of all massive varieties are either bleached or algae-covered.

This site displayed numerous examples of both bleached and unbleached colonies of the same species and growth form, at the same depth and general location. Notably this was especially obvious for Acropora sp. tables and Pocillopora sp. submassives. Other sites demonstrate this as well, especially in regards to the shallow massive colonies from Calalin to Enemanit Islands discussed earlier. This makes it difficult to identify reliable trends from the observations.

The common coral Heliopora coerulea did not bleach, which is especially good news for coastal protection as it provides much of the rugosity among spur-and-grooves on the oceanside reef crests in the RMI. There has also been no observed bleaching of giant clams.

Snorkel Dec 15-17th Oceanside Arno Arno, Arno Atoll Oceanside bleaching at Arno Arno, W Arno Atoll was observed by Remi Chauvin and Karl Mathiesen from the Guardian newspaper in London to be occurring Dec 15-17th. Significant white patches on coral colonies suggest that the event continues.

Consideration was given to the possibility that this bleaching occurred when bleaching was observed in Arno in mid-October by MIMRA, which would mean that these corals may be repopulated with zooxanthellae in time. This would be consistent with recent observations of SSTs returning to previous levels. However, this notion was largely discounted because SSTs were still somewhat elevated in mid-December, and there is significant mortality from bleaching. More realistic is probably some combination of lower thermal stress continuing to bleach and kill some corals quickly, while others remain bleached for longer periods of time. The difference from the situation in Majuro is that Arno has cleaner water, much less algae, and more grazing by herbivores. This has likely resulted in dead colonies being maintained sufficiently for coralline algae to grow, with the ensuing structure of the skeletons remaining largely intact and providing adequate surfaces for coral recruitment. This may be an optimistic view, especially in light of the limited monitoring that has taken place. Arno still has significant fishing pressure because of its proximity to Majuro, while other atolls in the RMI maintain higher herbivore variety and abundance. The implication is that rural areas have a chance at recovery, while populated centers are especially vulnerable to losing both fisheries habitat and shoreline protection services from the reef.

No details are offered on proportions of bleached and algae-covered colonies with respect to total cover or growth forms because the snorkelers documenting the bleaching do not have experience in this regard. However, the photos suggest that percentages would be less than that observed by UH Sea Grant and MIMRA in Majuro.

Historical Reference: In Sept-Oct 2013 there was localized bleaching on the oceanside reef flats in Delap-Uliga-Djarrit on Majuro, and along the west shores of Arno. Last February similar bleaching was seen in Jabor on Jaluit. There have been numerous reports over the years of localized bleaching in the RMI via MIMRA and the College of the Marshall Island’s former marine science professor Dr. Dean Jacobson. The photos below show massive Porites sp. bleaching off Denmeo Island East of Enemanit Island in 2009, and the ensuing partial recovery with characteristic lesions in 2011. The difference with the current event is in scale and severity of thermal stress. Further monitoring may attempt to re-visit this and other sites.