Page 1 of 2 12 LastLast
Results 1 to 10 of 19

Thread: Status and Trends of Bonaire’s Reefs: Cause for Grave Concerns (BNMP 2011 Report)

  1. #1
    wwguy's Avatar
    wwguy is offline Bonaire Lover SUPPORTING MEMBER - Bonaire Talker
    Join Date
    May 2011
    Posts
    585

    Exclamation Status and Trends of Bonaire’s Reefs: Cause for Grave Concerns (BNMP 2011 Report)

    For those concerned about the recent decline in the health of Bonaire's reefs, and for those who may be reluctant to concede that a negative change is occurring; I think you will find this report to be both informative and insightful.

    A new 137 page report titled Status and Trends of Bonaire’s Reefs: Cause for Grave Concerns was recently published in PDF format by the Bonaire National Marine Park (BNMP) on this webpage. Based on the title of the report, this would also seem to be the basis for the lecture with the same title scheduled to be given by Ramon de Leon, BNMP Manager, at the CIEE Research Station on Bonaire tomorrow night. If anyone reading this post attended that lecture, I'd appreciate reading a summary or your observations on the lecture and any resulting audience Q&A.

    The entire document is only 6MB, so downloading shouldn't be a problem. At a minimum I recommend reading the 7 page Executive Summary on pages 7 to 13.

    Paraphrased highlights from the Executive Summary section include:
    • Unusually warm ocean temperatures surrounding Bonaire during the late summer and fall of 2010 caused 10 to 20 % of corals to bleach.
    • Bleaching persisted long enough to kill about 10 % of the corals within six months of the event.
    • This increase in non-coral substrate (i.e. dead coral) increased the area algae can colonize, and the area parrotfish must keep cropped short.
    • Thus, herbivorous fish (parrotfish and sea urchin) biomass and population densities would have to increase for there to be no incremental change in seaweed (algae) abundance, but they have been steadily declining in recent years.
    • A decline in parrotfish and sea urchin numbers continues despite the establishment of no-take areas, called Fish Protection Areas (FPAs) and the recent law that completely bans the harvesting of parrotfish.
    • Damselfishes continue to increase in abundance (except in FPAs) and their aggressive territoriality reduces parrotfish algae-eating activity where they are present.
    • The declines in herbivory algae eaters resulted in a marked increase in macroalgae.
    • All research to date indicates that coral health and recruitment declines directly with increases in algal abundance.

    To put it a simply as possible: Warm water killed 10% of the coral, which resulted in 10% more surface for the "bad" kind of algae to grow. In a balanced ecosystem bad algae would normally be eaten by parrotfish and urchins. But parrotfish and sea urchin numbers are steadily declining for other reasons, rather than increasing, which further propagates the growth of more bad algae. Further complicating matters, Coralline algae, the "good" algae which has been shown to facilitate coral recruitment, remains at or near unprecedentedly low levels. More bad algae and less good algae results in declining coral health and inhibited coral reproduction... and so the cycle continues in a downward spiral.

    Thus the report's Executive Summary conclusion:
    "Overall, Bonaire’s coral reefs today are more seriously threatened with collapse than at any time since monitoring began in 1999."

    There is a little bit of good new in this report however: Predatory fishes including snappers, groupers, barracuda, grunts and others increased in abundance at the monitored sites. Unfortunately, specific predators known to eat damselfishes showed variable population densities with only a hint of an increase in 2011.

    The final paragraph of the executive summary contains this ominous warning:
    "The trend of greatest concern is the steady decline in parrotfish abundance despite very recent laws banning their harvest. It is possible that the timing of the bleaching event may have increased the area for algal colonization such that existing herbivores were overwhelmed by rapid algal growth which may negatively affect subsequent herbivory (see discussion in McMahan Chapter 4). If so, this would suggest Bonaire’s coral reefs could be slipping into a feedback loop that could continue and drive the reef towards a coral depleted state (Mumby and Steneck 2008)."

    I confess that I haven't read the report in it's entirety yet, but I will soon. The information above is skimmed and/or paraphrased from the Executive Summary section.

    I'm very much interested in what you all think about this report, and about what you think we can do to slow, stop, or reverse this downward trend in the health of our beloved reefs. After I've spent some time pondering, I plan to return to this thread to post some examples of what we may be able to do, both individually and collectively, to mitigate or reduce our negative impact on Bonaire's delicate ecosystem.

    Ten years ago I brought my teenage son to Bonaire for his first Caribbean dive trip. Next month I'll welcome my first grandson into the world and I'd like to dive with him on Bonaire someday too. I can't help but wonder what Bonaire's reefs, and the other reefs in the world, will be like in another 15 years. Right now the future doesn't seem to be looking very bright.

    For now... Happy Diving.

    -Roger

  2. #2
    coldwaterlloyd Lurker

    Default

    Thanks for posting Roger . It is the smoking gun that reefs are endangerd and instant action should be taken to try to at least stop the pollution , which is like throwing gas on fire .

  3. #3
    Join Date
    May 2011
    Location
    Overlooking Lake Winnipesaukee in New Hampshire and "VINIBU" on Bonaire
    Posts
    337

    Default

    Roger..Thanks much for posting this. The more heightened awareness we have, I think the better the local government can pass the appropriate laws to protect the reef. I'm sorry I'm not on island to attend Ramon's lecture tomorrow evening! I do remember the waters were EXTREMELY warm the summer 2010.
    "Life is good, And on Bonaire, It's even better!"


    Owner of VINIBU

  4. #4
    Join Date
    May 2011
    Location
    Citrus Heights CA
    Posts
    643

    Default

    Will an island wide functioning sewer system, should that ever become a reality, help in limiting algea growth?

  5. #5
    randl's Avatar
    randl is offline Bonaire Lover SUPPORTING MEMBER - Bonaire Talker
    Join Date
    Sep 2011
    Location
    Houston TX, Los Angeles CA and Bonaire
    Posts
    546

    Default

    Quote Originally Posted by grunt View Post
    Will an island wide functioning sewer system, should that ever become a reality, help in limiting algea growth?
    I'm still making my way through the report but it does seem to play down the role of nutrients in the problem. For example, it reads, "Most studies have shown that herbivory from scraping herbivores such as parrotfishes and sea urchins controls algal abundance much more strongly than nutrient availablity (McCook 1999, Williams and Polunin 2001, Kramer 2003, and Mumby and Steneck 2008). Other studies have indicated that herbivores facilitate coralline algal abundance (van den Hoek 1969, Steneck 1986, 1988, 1997, Steneck and Dethier 1994, Edmunds and Carpenter 2001)."

    On the other hand, it adds, "...other local measures can be taken to mitigate stress on reefs, including improving land use practices such as restricting coastal development and reducing nutrient input."

    On balance, the report places the cause of the decline of corals on higher ocean temperatures along with a reduction in herbivore activity to control the algae. Of course anything that controls algae in addition to parrotfish would be helpful.

  6. #6
    tursiops's Avatar
    tursiops is offline Bonaire Lover SUPPORTING MEMBER - Bonaire Talker
    Join Date
    May 2011
    Location
    Alexandria, Virginia
    Posts
    493

    Default

    The euphemisms are remarkable. "...reduction in herbivore activity..." Let's just call it overfishing by the locals, to whom the rules do not apply, or against whom the rules are not enforced. It has been going on forever, but has reached its tipping point. Who among us has not seen that fishing taking place?
    Mel Briscoe, Alexandria, Virginia

  7. #7
    smits is offline Bonaire Lover SUPPORTING MEMBER - Bonaire Talker
    Join Date
    May 2011
    Posts
    477

    Default

    Lets just NOT call it overfishing by the locals.
    The real overfishing is done by the "developed" world, using factory ships.

    This is what Stinapa says:

    Fishing
    Bonaire is popular for fishing. We recommend targeting blue water fish and leaving our reef fish on the reefs. Trolling along our protected west coast often attracts tuna, wahoo, barracuda or mahi mahi. The best places to bone fish are Lagun or the Sorobon side of Lac, in the area called ‘Aw’i Meuchi”. Bone fishing or any type of fishing activity is not allowed in the salt flats. Fishing can only be done with line and hook. We recommend practicing catch and release at all times. Taking sea turtles or conch, or using a spear gun or hand spear is prohibited by law.

    The local fisherman you see fishing on our reefs have been doing so for generations. To many it is their only source of income. Please do not cut their fishing lines!

  8. #8
    tursiops's Avatar
    tursiops is offline Bonaire Lover SUPPORTING MEMBER - Bonaire Talker
    Join Date
    May 2011
    Location
    Alexandria, Virginia
    Posts
    493

    Default

    Come on Smits; are you really saying that the Bonairian parrotfish are gone because of factory ships in the developed world?

    Nothing in the Stinapa statement mention over fishing or sustainability. What it says is the locals have been fishing the reefs for generations. That is exactly my point: the locals are the only people fishing the reefs, the parrotfish are gone. The locals passed the tipping point without any thought as to sustainability....just doing what they've always done. Too much, for too long.
    Mel Briscoe, Alexandria, Virginia

  9. #9
    coldwaterlloyd Lurker

    Default

    Combination of pollution , over fishing , a chain reaction starts . We are witnessing the end of coral reefs as we know them . It was predicted twenty years ago .

  10. #10
    smits is offline Bonaire Lover SUPPORTING MEMBER - Bonaire Talker
    Join Date
    May 2011
    Posts
    477

    Default

    @tursiops
    No, that is not what I wanted to make clear.

    Saying that the locals are overfishing is in my opinion much too strong a statement. They are fishing for generations. very often with line and hook. Sometimes with nets.

    The real overfishing in the oceans is done by the factory ships of the "developed" nations.

    Probably "us tourists" do more harm to the ecoligcal system.
    We fly to Bonaire, use the stressed sewage system, drive our cars over the island, or arrive with cruise ships.

    And that on an island that, not so very long ago, used to have 9.000 inhabitants. With all the financial restrictions.

    And I'll admit. I'm part of that problem too,
    I vist Bonaire since 1977. The situation of the reef and the fish population is incomparable to that time.
    And that is not because locals are overfishing.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •