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Sep 10 2012

Coral reefs on the Eco-Doom beat

Caribbean Reef Octopus Takes a Stand

ObCephalopod: Cayman Islands reef octopus faces down boring vertebrate (Creative Commons photo by Pete)

The International Union for the Conservation of Nature’s World Conservation Congress is taking place right now in South Korea, and a report from Friday’s session is trickling through various social media, including The New York Times’ Green blog: Caribbean coral reefs are in trouble.

From the WCC’s coral reef workshop’s Executive Summary (PDF):

Some Caribbean reef ecosystems are relatively intact compared to average conditions in the region. For example, many reefs in the Netherlands Antilles and Cayman Islands have 30% or more live coral cover, little macroalgae, and a moderate (albeit strongly depleted) abundance of fish. In contrast, reefs in Jamaica  and the US Virgin Islands have well below 10% live coral cover, abundant macroalgae, and virtually no fish larger than a few cm.

When local reefs that are 70% dead qualifies as “relatively intact compared  to average conditions in the region,”  headlines like NatGeo’s “Caribbean Coral Reefs Mostly Dead, IUCN Says” stop seeming quite so alarmist.

The issue with macroalgae is that they encroach on coral reefs and compete with the coral organisms. They’re often present in healthy reefs, kept in control by algae-eating animals. When those fish aren’t there for one reason or another, or when a reef gets a big shot of extra nutrients from on-shore fertilizers or eroded soil, the algae can get out of hand.

The Smithsonian Tropical Research Institute assembled 36 scientists in Panama to assess the region’s coral reefs, and the results of that work are what were presented at the WCC Friday. Researchers are pinning the damage on human interference. The precise mechanism by which we’re killing  the reefs is open to question, but they have some prime suspects:

Caribbean reefs with the highest surviving coral cover and least macroalgae tend to be characterized by little land-based pollution, some degree of fisheries regulations and enforcement, moderate economic prosperity, and lower frequency of hurricanes, coral bleaching, and disease.

The team will have a more complete analysis of their data by mid-2013, and plan to expand their survey to other oceans’ reefs by 2016.

This isn’t a surprise: the degradation of Caribbean reefs has been talked for decades. Coral reefs serve as nurseries for commercially important fish species, they absorb wave energy and thus shelter coastlines from storm damage, and they’re just full of fascinating critters. Reefs can recover from our damage if we start to protect them: parts of Australia’s Great Barrier Reef recently recovered from bleaching events a lot more quickly than scientists had hoped.

But it’s still awful news.

18 comments

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  1. 1
    Gregory in Seattle

    Another important consideration: eco-tourism. Those reefs represent tens of millions of dollars each year pumped into their economy from foreigners who are eager to come and see them in person. If for no other reason than simple economics, there is a strong incentive to mitigate the damage and restore the reefs.

  2. 2
    chrispj

    A few things. First, our best estimate is that mean historic hard coral coverage in the region was around 50% (higher in some places, lower in others, depending mostly on recent disturbance, but a mean of 50%). Therefore, coral cover of 30% is a 40% reduction relative to baseline values, not a 70% reduction. The reefs are not 70% dead. This isn’t great by any means, but it’s much better than the 80-95% decline in hard coral cover in other parts of the Caribbean (e.g., much of Jamaica, Virgin Islands, Florida Keys).

    Second, there’s a typo above–it it macroalgae blooms that have proven problematic, not microalgae.

    Third, I would strongly disagree that the precise mechanisms by which we are killing reefs is “an open question” as would just about everyone else I know in this field. We understand in excruciating detail the major mechanisms that kill reefs. There are always new things to learn, but the recipe to kill reefs is simple and well understood.

    Fourth, there’s a typo near the end–parts of the GBR recovered from bleaching (I assume you’re talking about the Keppel Islands after the 2006 bleaching???) much faster than expected, not faster than hoped. This rapid recovery on some of the reefs was a huge relief.

    Last, things are really not good for reefs, and are getting worse, but places like the Dutch Antilles, the Cayman Islands, and even a few spots around Jamaica which have shown surprising signs of recovery in recent years suggest that there are reasons to hold out hope for the future of reefs, if we start getting our act together that is.

  3. 3
    julielada

    As someone doing artificial reef and fish recruitment/sustainability research in the Caribbean, I resent the boring vertebrate remark!

  4. 4
    Chris Clarke

    Thanks for the clarification on baseline percentages and for spotting the typo, which I’ve fixed.

    Third, I would strongly disagree that the precise mechanisms by which we are killing reefs is “an open question” as would just about everyone else I know in this field. We understand in excruciating detail the major mechanisms that kill reefs. There are always new things to learn, but the recipe to kill reefs is simple and well understood.

    Yep. But the precise mix of those well established causes that is killing the reefs in the Caribbean is not known, as is said in the PDF to which I linked. That’s what I was trying to say in the sentence you object to : sorry if that wasn’t clear.

  5. 5
    julielada

    P.S. A huge problem for us down here in St. Kitts is lionfish. They’re invasive, they have no natural predators, and they strip reefs bare. And the real kicker is we can’t even eat them to try and keep the population down because of ciguatera.

  6. 6
    Chris Clarke

    I resent the boring vertebrate remark!

    Hey, some of my best friends, etc.

  7. 7
    Pierce R. Butler

    Yet the IUCN continues to disregard the major coral reef damage to be inflicted by construction of a US Navy base, and vigorously protested by the people of the nearby fishing village of Gangjeong (who are facing involuntary displacement), just a few miles from the site of the IUCN’s international convention.

  8. 8
    viajera

    Yet the IUCN continues to disregard the major coral reef damage to be inflicted by construction of a US Navy base, and vigorously protested by the people of the nearby fishing village of Gangjeong (who are facing involuntary displacement)

    I’ve snorkeled off of many Caribbean Islands, Pacific and Atlantic coasts of Central America, and Hawaii, and you know where I found the most beautiful and utterly-pristine-to-my-eyes coral reefs? Guantanamo Bay, Cuba. Seriously. I’m a hippie peacenik and if you’d asked me 15 years ago if I’d ever support anything about the military, I’d have laughed in your face. But I’ve worked on a lot of bases and one thing the US military is good for is locking up large chunks of land and keeping people away from it. Fort Leavenworth has, IIRC, one of the largest remaining tracts of old-growth riparian hardwood in the Plains. Fort Hood supports some of the largest breeding populations of the endangered Golden-cheeked Warbler and Black-capped Vireo. And so on.

    Not to say that the construction of this specific base won’t damage the reef – I don’t know anything about the plans. But I wouldn’t immediately jump to that conclusion.

    Now, the exclusion of the local villagers is another story. But seeing as overfishing is one of the big drivers of reef deterioration, keeping fishermen out will likely benefit the reef, if not the people.

  9. 9
    Pierce R. Butler

    An update from Jeju Island has it that the IUCN leadership has changed its policy and is now giving local activists from Gangjeong full run of the global conference (though reportedly S. Korean police continue heavy harassment at the village itself, 7 km away).

    Last I heard, the US base at Guantanamo has been refitted as a detention and torture camp; the one planned for Jeju (a UNESCO “World Heritage Site”, claimed to include the largest temperate Octocoral forests on Earth) is a much larger naval station for submarines, aircraft carriers, and the like intended as a key strongpoint to “contain” Chinese naval power (i.e., control oil importation routes). Such facilities tend to cause more ecological damage than those which just hose some blood into the water once in a while.

  10. 10
    Dutchgirl

    I logged in as soon as I read the post to make some corrections, but chrispj beat me to it with the same objections/corrections. Not that I am any sort of expert, just a well read lay person after proof reading all of my husbands research. (He did a coral study in Curacao and in Waageningen)
    Hawaii, where I live, is having issues with invasive seaweed and a few other critters. While the large animals on the protected/endangered species list have done very well here, reef preservation has not been a major priority and it shows.

  11. 11
    chrispj

    Dutchgirl, small world. I did a chunk of my M.S. in Curacao (wonderful, wonderful place) and now I’m working on the Ph.D. here on O’ahu :)

  12. 12
    Ragutis

    julielada
    10 September 2012 at 6:25 pm

    P.S. A huge problem for us down here in St. Kitts is lionfish. They’re invasive, they have no natural predators, and they strip reefs bare. And the real kicker is we can’t even eat them to try and keep the population down because of ciguatera.

    You aren’t alone.

    They’ve spread as far north as N.Carolina.

    As for the ciguatera, is there any good evidence that they are any riskier than other reef predators? Folks stay away from barracudas because of it, but I’ve never heard of anyone tossing back a yellowtail or gag out of concern.

  13. 13
    julietdefarge

    Korean and Okinawan reefs are in danger, too – from expanding US military bases.

  14. 14
    julielada

    Ragutis: All I know is that my PI told me that lionfish in the Caribbean are no longer safe to eat. From what I understand, because lionfish are such undiscriminate feeders and act as carnivorous Hoover beasts, they accumulate ciguatera more than some other species of predatory fish.

  15. 15
    julielada

    And of course I meant “indiscriminate”. Oy.

  16. 16
    chrispj

    There’s been some possible detection of ciguatera in lionfish from some places in the Caribbean, but no indication of it in other places. They’re getting harvested for food in a lot of places now. If there’s one thing human society is good at, it’s overfishing, and I’m hoping folks go to town on them.

    Detection of ciguatera is potentially problematic though. From what I hear from a person that works with this sort of thing, the typical assay relys on a bioassay and the reaction of cells to an extract of the fish. Apparently actually detecting ciguatoxin is challenging. The problem is that the venom from scorpaeniforms can potentially mimic similar effects in the bioassay, giving a false positive. We know that there is a lot of venom that can be delivered by the dorsal spines of lionfish, but we don’t know much about its distribution beyond that. Recent phylogentic has found that groupers and other serranids are actually closely allied with scorpaeniforms, so groupers may be mildly venomous. In fact, work a friend has done found that younger, smaller groupers which should have *much* less ciquatoxin than larger individuals tend to test positive for it more often. This suggests that perhaps we have gotten a lot of false positives with these sorts of fish. Unlike ciguatoxin, venoms from scorpaeniform fish and (if they produce venoms) serranids is protein-based and is denatured by cooking.

    Offshore of North Carolina was one of the places that lionfish populations first exploded. They’ve been there at high abundance (mostly offshore in deeper water, kept warmer by the Gulf Stream) for many years. It’s just in the past few years that they’ve spread to the far flung parts of the Caribbean and Gulf. Larvae make it at least as far north as Long Island and you can typically find large numbers of juveniles off Long Island every summer. They don’t seem to be able to survive the winter cold north of the Outer Banks (NC) though.

    Maybe I’m missing something, but isn’t the proposed Jeju naval base a South Korean base, not a US one? Sucks either way. This is a subtropical soft coral community though, not a tropical coral reef. It’s a different ecosystem. It’s beautiful though and I hope it can be preserved.

  17. 17
    Dutchgirl

    chrispj: small world indeed. I think such randomness should be celebrated with a beer and maybe some local grinds. My husband did his research on Curacao five years ago, you?

  18. 18
    Pierce R. Butler

    chrispj @ # 16: … isn’t the proposed Jeju naval base a South Korean base, not a US one?

    Nope, unless the S. Korean Navy has suddenly acquired a bunch of nuclear subs and aircraft carriers which they’re operating under the US flag.

    To monitor Jeju Island developments (now apparently moving faster since the international environmental community has finally taken notice), see Save Jeju Now.

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