Coral Bleaching
Every now and then I cast my eye around to see what is happening to coral reefs, hoping to find some good news. For several months now, NOAA’s Coral Reef Watch program has been predicting a worsening bleaching season as 2015 rolls out. The on-again, off-again el Niño that was being forecast through much of 2014 has finally arrived, although it is a pretty weak one. Still, it is the first bona-fide el Niño since 2010, and that four-year gap is the longest between el Niños since the 1970’s. NOAA’s Climate Prediction Service formally confirmed the arrival of el Niño conditions in March, and in April reported a 50-60% likelihood that el Niño conditions would persist through the northern summer.
Graph of eastern Pacific sea surface temperature anomaly from early 2014 to end of 2015. Black solid line is observed (as running 3 month mean), while the multitude of colored lines are future projections from different models. All models are projecting a continuation of positive anomalies, and associated el Niño conditions, until end of 2015. Graph courtesy NOAA Climate Prediction Center.
For March to June 2015, NOAA’s Coral Reef Watch is predicting conditions that favor coral bleaching in much of the southwest Pacific and northwest of Australia. There was significant bleaching on Hawaiian reefs, and in the Marshall Islands, Marianas, and Kiribati late in 2014, and reefs off the Solomon Islands, Vanuatu, Tuvalu, Fiji and the Samoas have been hit hard by warm waters in the first months of 2015. Conditions leading to bleaching are likely to appear in more northerly locations as the northern summer progresses. As most of us know by now, bleaching is simply a stress response by corals to warmer than usual water, in which the symbiotic algal cells within the coral’s tissues are expelled, leaving the translucent coral polyp through which the white skeleton is clearly visible. Corals can recover from bleaching if the stressful conditions do not last too long, but if conditions persist for a couple of weeks, a substantial proportion of the coral will die.
Map showing the level of risk for a bleaching event during the March to June, 2015, period.
Map courtesy NOAA CRW.
The bleaching in the Marshalls and Marianas began in mid-September, and has been unprecedented according to reports. Fortunately, the el Niño has remained relatively weak so far, and the bleaching events in other regions as the season progresses are not expected to be as extreme as those in 2010 or in 1998. The next region in which to watch as the season develops will be the Indian Ocean.
Every time reefs bleach sufficiently to cause widespread mortality, reefs are being degraded. Enhanced coral mortality, over time, progressively reduces abundance of living corals, thereby reducing the capacity of the reef to grow sufficiently to counteract the continuous erosion due to wave action and the activities of numerous bioeroder species of worms, molluscs, sponges and fish. Over time, reefs become less extensive than they were. This is a tale of slow destruction; one that is still being written.
Inappropriate coastal development
Coral bleaching is just one of the many ways in which humans are degrading reefs. In February, reports in the Los Angeles Times and on a website maintained by the Asia Maritime Transparency Initiative (AMTI) revealed very extensive island building by China on the contested Spratly Reefs in the South China Sea. The Spratlys, which lie far closer to the coast of the Philippines than to China, are valued fishing grounds, and possible sites for oil exploration. China, Vietnam, the Philippines, Taiwan, Brunei and Malaysia have all, from time to time, maintained territorial claims, often by stationing a few troops at temporary camps on one or other of the many islands. China’s current activities go far beyond that however – the development taking place is massive, involves construction of extensive new land, including aircraft runways and wharfs for large vessels, as well as military structures. The construction is using all the methods pioneered so badly off the coast of Dubai, especially use of large cutter dredges with no silt curtains visible. There is no information available on the impacts on reefs, but it is impossible to believe it is not substantial. (A post on the AMTI website yesterday up-dates information on Mischief Reef; a place that had no land a decade ago when smaller-scale construction activities first happened.)
Fiery Cross Reef, Spratly Islands, where China has increased the area of the land mass from 0.08 km2 to 0.96 km2 commencing in August 2014. A garrison of 200 troops is stationed there and an airstrip may be under construction. Vessels visible in the harbor are dredges. Photo © CSIS AMTI.
Of course, what is happening in the Spratlys is nothing new. While China has not been talking about what it is doing in the Spratly Islands, and certainly not claiming that it is doing it in an environmentally sustainable way, many others are ‘developing’ around reefs in inappropriate ways while claiming all is well. The Australian government is currently pretending that it is possible to develop enormous new coal terminals up and down the Queensland coast, with all the dredging that will entail, without causing any damage to the Great Barrier Reef. The reef management authority’s own data on water quality show that quality has declined particularly on near-shore parts of the GBR region, simply due to the expanded agriculture along the Queensland coast, and suggestions that dumping of dredge spoil within the reef area will not cause significant damage are made with much waving of arms, while the economic necessity of exporting as much coal as possible as quickly as possible to Asian markets is trumpeted as if that fact is beyond question. Why is it suddenly necessary to export coal much more rapidly than before? Because the window for cashing in on immense coal reserves is closing rapidly, and cashing in is apparently far more important to the current Australian (and Queensland) governments than caring for the world’s largest, most iconic, reef system. Funny how economic necessity is so often seen as far more necessary than ecological necessity (but then, I don’t own shares in any of Australia’s coal producers).
In August 2013, Norwegian Cruise Line announced a $50 million plan to build a new cruise terminal in Belize. Based at Harvest Caye, a 30ha speck of land about 1km off shore and 6km south of the town of Placencia, the new development was going to be an “eco-friendly” destination with a floating pier, island village with raised-platform structures, a marina, a lagoon for water sports and a beach. In its contract with the Belize government, Norwegian agreed to adhere to the country’s environmental standards, employ locals during construction and create a hiring program for Belizeans who want to work on its ships. Once Harvest Caye opens, those people are to have preference for staff positions. In a news report at the time, Norwegian CEO Kevin Sheehan stated “in our quest to continuously look for new and exciting destinations for our guests, we plan to develop a cruise destination focused on sustainable design and eco-friendly principles that will retain the natural beauty and local culture of this tropical paradise.” He added that they also plan to bring four times as many tourists to Belize as they were doing before.
In the nearly two years since, it has become apparent that this is yet another example of big tourism running a steamroller through a developing country. Apart from the fact that this ‘eco-friendly’ development is going to result in the delivery of 2500 tourists a day to this tiny speck of land, and is going to set up the usual inter-connected structure of shore transport and land-based tourism opportunities all controlled by the cruise line (with profits racing out of the country to Norwegian’s offices in Miami), thereby cutting most of Belize out of the economic benefits, the agreement with the government (which is exuberantly in favor of the development) is financially very favorable to the cruise line. And then there are the environmental aspects.
Aerial view showing the extent of modification to Harvest Caye for Norwegian Cruise Line’s “eco-friendly” complex. Photo © Annelise Hagan
The Environmental Impact Assessment was made public in an information meeting in a nearby town in January 2014, and appeared to have a number of deficiencies. For one thing, it was an EIA done in 2009 for a subsequently abandoned project at that site that would have included an airstrip in place of a floating cruise ship terminal! Despite protests, and an effort by the Belize Tourism Industry Association to block the project in the courts, work on the development proceeded. (The appeal to the courts was successful, but that seems not sufficient to stop a development project wanted by leading members of government.) Extensive modifications on the island, including removal of large areas of mangroves, and dredging and filling around its edges commenced by mid-2014, and, predictably, by February 2015, the first reports of direct damage to coral formations began to surface. Time will tell how well this project is executed, but it seems to be moving along a well-worn path of mediocre respect for the environment. Eco-friendly, indeed.
Overfishing
An important new paper appeared on the Nature website this week. Aaron MacNeil of the Australian Institute of Marine Science, together with 10 colleagues from Australia, the UK and the US, has evaluated the status of reef fish communities on 832 coral reefs around the world. Overfishing on coral reefs is very widespread, and probably the most common way in which we degrade coral reef systems. Overfishing not only removes fish biomass and leads to changes in the structure of fish communities, it also reduces major ecosystem services – the continuous grazing on filamentous and larger algae, and the scraping away of reef rock by certain of the herbivores that free up patches of newly exposed, fresh carbonate rock surfaces ripe for coral colonization. Loss of this herbivory leads to substantial change in the dynamic between corals and algae, and can lead to massive phase shifts tipping a reef from coral- to algae-dominated.
By examining 22 remote reefs (>200km from human communities), both fished and protected, they were able to describe the range of biomass likely for unfished reefs. This varied from about 500 to 4,400 kg per hectare depending on differences among reefs such as level of productivity, extent of coral cover, and whether the location was an atoll or a more coastal reef. By arraying the less remote, protected locations relative to age of reserve, they revealed an asymptotic relationship between biomass in kg per hectare and duration of protection. Their results show that the average biomass of fish on a reef is about 1000 kg per hectare, and that the vast majority of fished reefs have biomass less than half this amount.
Current fish biomass on reefs that are fished, and those where fishing is restricted. An undepleted reef should have biomass approaching Bo. Most reefs near people are depleted to 50% or less of Bo, but reefs with some fishing protection are much less depleted than others. Figure © Nature
Part C of MacNeil’s Figure 2, showing the likely time to full recovery of fish biomass for each site, if protected effectively from fishing. Figure © Nature
Effective protection leads to recovery of biomass within 35 years on average, and the most depleted sites can recover in about 60 years. They also show that partially effective MPA protection, or mechanisms to restrict fishing effort such as gear restrictions both have useful effects on biomass.
Their results are important for two reasons. First is the confirmation of the pervasive impacts of overfishing on most reefs accessible to human settlement around the world. We have had a profound impact on reefs through our fishing activities. Secondly, they show the length of time required for recovery from an overfished state, and confirm that use of MPAs to reduce fishing effort is not the only effective management method available. This latter point offers managers a suite of possible approaches to choose from, some of which may be more appropriate than others in each specific locality. That overfishing can be corrected substantially within 35 years or so is also encouraging news.
School of big-eye trevally on a reef in American Samoa. Photo © Ben Ruttenburg, NOAA NMFS
Aaron MacNeil was also co-author of an article published on-line in Current Biology last week, and due to appear in the April issue of that journal. Led by Michael Emslie of Australian Institute of Marine Science, the 14 authors from various Australian institutions report on the performance of the network of no-take marine reserves (NTMR) within the Great Barrier Reef Marine Park, since the area was rezoned in 2006. Their results confirm that this system of well-managed fishery reserves has performed as expected to enhance abundance and size of coral trout (Plectropomus sp.) the primary species in the Queensland commercial and sport fishery. Their study also provides evidence for some indirect benefits of NTMR networks on other members of the reef ecosystem, while making clear that NTMRs or other types of MPA can never protect a coral reef from forms of degradation such as tropical storms or climate change. Taken together, these two articles are strong evidence for our ability to manage overfishing, and managing this particular issue is definitely worth doing on coral reefs throughout the world. Now all we have to do is get out there and enforce the management rules that we already have in place in the great majority of reefs where fishing occurs.
Do we really care about coral reefs?
That we are so consistent in our mismanagement of coral reefs around the world should cause us to ask, Do we really care about these iconic ecosystems, or not? Appeals to conserve coral reefs have been being made around the world since at least the early 1960s when the impacts of crown-of-thorns starfish outbreaks were first observed. Thousands of MPAs have been established around coral reefs. The global mass bleaching event of 1998 galvanized opinion, and ever stronger calls to address climate change before it became too late. And still we mismanage them. I sometimes wonder if we really are incapable for watching out for slowly moving threats, such as the gradual degradation of coral reefs, or the gradual melting of a glacier, or the gradual rise of sea level. Maybe we really are only capable of getting out of the way of sabre-toothed cats? Or maybe we just have to try a little bit harder?
Something the sport diving industry could help with?
I’ve recently been following an online discussion on whether the sport diving industry should do more to work for conservation of coral reefs. The e-mail list, coral list forum, is managed by NOAA’s Coral Health and Monitoring Program, and is a world-wide discussion of things coral reef. And discussions on topics related to climate change and reef conservation crop up from time to time. The sport dive industry is just one of many industries that makes use of coral reefs and certainly not the largest, but sport divers do get particularly close to coral reefs – more so than most other tourists to tropical coasts – so it would make sense for this industry to be particularly concerned about reef conservation. Still, while there are some exemplary exceptions providing reef experiences to sport divers around the world, the sad fact is that most operators do very little to ensure their own operations are not harmful, and next to nothing to educate the divers about the threats to reefs.
The sport diving community uses coral reefs such as these in the Red Sea. Should this community play a significant role in promoting the conservation of reefs? Photo © Kuwait Diving Team
As one participant in the discussion ruefully pointed out, the great majority of sport divers cannot tell the difference between a coral reef in good condition and one that has been extensively degraded. So long as they emerge at the end of a dive with the sense they had a fun time, all seems well. While there are some sport divers with considerable experience, knowledge and skill, most have little if any knowledge of coral reefs, and relatively few dives under their belts following training programs that each year become more compressed and more limited in terms on hands-on time in the water.
When one’s customers cannot tell the difference between an excellent and a mediocre dive location, and when nobody in authority is requiring certain performance standards, it’s not too surprising if dive operators do not put on much of an effort to conserve and to educate. Yet motivated sport divers could be powerful advocates for reef conservation – most of them come from the developed world, with some disposable income, and some time to be environmentally active. If they are not being motivated in favor of reef conservation, what hope is there that other tourists to tropical shores will be motivated – many of them do not even venture beyond the hotel swimming pools.
What should we expect of the sport diving industry? I suggest that, at minimum, we should expect them to be operating in as environmentally responsible a manner as possible. As an industry that depends upon the interest of the sport diving community in exploring natural environments, albeit with the occasional rusting wreck thrown in for good measure, dive operators should be leading by example, making their operations as environmentally sustainable as possible.
Granted, they will likely be using fossil fuel to power their vessels and the compressors that refill the tanks after each dive, but they could still ensure that their engines are operating efficiently, not dripping oil into the ocean, and, on shore they could look towards use of electrical power from non-fossil fuel sources where possible. Regardless of the source of fuel, they can operate their vessels efficiently, and with due consideration for the damage a vessel can cause to coral reefs, or to other marine environments via prop wash, mooring, anchoring, or running aground, and should certainly not be disposing of wastes of any type at sea.
In addition, they should take more care than most of them do to ensure that the sport divers accompanying them to a reef are given instruction on how to operate in a reef environment so as to avoid inadvertent damage through bumping into, grabbing onto, kicking, or standing on delicate organisms that cannot sustain such abuse by hundreds of divers in succession, day after day. As another contributor noted, it is amazing to see just how mediocre are the buoyancy-control skills of the average sport diver.
That point about buoyancy reminds me of an occasion when I was involved in a training program for MPA management staff on how to carry out in-water monitoring of reef condition.
This took place in a region with many reef MPAs and a significant sport dive industry, and no I am not going to name the location or year! In truth, it was not a well-organized training workshop, but I was still amazed at the lack of diving proficiency of MPA staff who had been hand-picked to participate in the course because they were experienced MPA biologists, the people who had been, and would in future, be leading reef monitoring activities taking place back at their home MPA. The classroom sessions went quite well, despite some minor English-Spanish-French communication issues, but when we got out in a boat and prepared to get into the water, our excellence degraded.
It rapidly became clear to me that tasking many of the participants with carrying a tape measure, and a slate with a printed data sheet on waterproof paper, while also diving, was a task too many. Divers, head down, wrapped up in loop after loop of the unreeling tape, and looking for all the world like an unwrapping mummy that had found its way into the ocean. Divers bouncing over the bottom, or absent-mindedly floating off into midwater space. Divers totally disoriented, unable to lay out the tape in a straight line and then swim along it. They were not impossibly bad. In fact they reminded me of groups of undergraduates on a field course – students who had dived before, but rarely on a reef, and never while tasked to actually do anything beyond diving.
If these are typical of MPA staff (and they are), we cannot expect any more from sport divers who have never been on a reef before. My experience of sport diving is not extensive; I got plenty of diving being a scientist. But it is probably representative, and I’ve always been struck by the lack of information provided about the dive site to be visited, about the organisms one might see there, or about special places or species to watch out for. Usually, the dive leaders are as talkative before and after the dive as they are during it, which means not very! I guess if I was trying to keep track of a bunch of divers I’ve never met before, of skill levels I am not very sure about, one or more of which will certainly wander off and have to be encouraged back to the herd, while at least one or two others will exhaust their tanks in world record time, yet look surprised when the gauge shows empty and they need to ascend… I’d probably begin to see my job as putting them in, and getting them all out and back on board still alive. But this is why I am not a divemaster.
The better dive leader will spend some time talking with each of his/her divers before the vessel even leaves the dock, and will have available on board, preferably on laminated waterproof sheets, ID guides for the more common corals and fishes, a simple list of do’s and don’t’s once in the water, and perhaps a map of the site showing bathymetry and route to be taken. A refresher lesson on buoyancy control on the way out to the site would also be useful for many sport divers, especially when they have rented gear and may not be familiar with its particular features.
Where sport diving is taking place inside a well-managed MPA, it would make sense for the MPA managers to formally lease exclusive use of specific dive sites to specific operators, or to co-ops formed by several smaller operators. This happens in very few places, partly perhaps because so few MPAs are well managed, but having ‘ownership’ of a dive site does engender more responsible behavior by the dive operator, and could go a long way to improve compliance with the simple rules for operating around reefs that all operators should know.
It has been said that people only care about taking care of those they love. Coral reefs are not loved by very many people because while they are beautiful to see, and fascinating to learn about, they are ‘the other’. They are remote for many of us, and we do not experience them except fleetingly while breathing air out of a tank, and unable to talk about them with each other until we emerge back to the surface. Sport divers could do much to advocate for coral reefs. There seems room for improvement in how they are being informed about and connected to reefs. Until they are properly connected, until they love reefs as more than places to dive, they will not be the advocates they could be.