Tag Archives: Coral Reefs

Australia suffers not only the loss of coral reefs.

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Research just in reveals that extreme events from climate change (2011-2017) have damaged 45% of Australia’s coastal habitats, including coral reefs, mangroves, kelp forests and seagrass.  These habitats provide food and shelter for a huge range of marine and estuarine species, including large fish, turtles and dugongs.  Vital for fisheries, these key habitats are also used and much loved by local and international visitors. 

The rate of their loss is extremely worrying, especially given that these changes have essentially occurred during an increase in global temperature of 1°C above the preindustrial era. As we go towards warming of 1.5oC, these serious impacts are more than likely to be amplified.

Extreme weather likely behind worst recorded mangrove dieback in northern Australia (Photo: Norm Duke)

Much of the damage has been driven by unusually long and hot underwater heat waves.  Other changes have been due to knock-on effects.  For example, large amounts of kelp forests have disappeared from the south-east coast of Australia due to the spread of sea urchins and tropical grazing fish species as higher latitudes warm.

The future is of concern.  The authors used ecosystem models to evaluate long-term outcomes from changing extreme events, which are predicted to become more frequent and intense with return times diminishing rapidly.  In the latter case, this means that many ecosystems are failing to recover in time prior to the next extreme event.

Check out the peer-reviewed study here.

 

 

Marine Protected Areas (MPA’s) gazetted in resource-poor areas of the seascape

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IndoReef500x333

Theres a new paper out by Edgar et al in Ecological Applications that tracks the ecosystem effects of 14 MPA’s, and exploited companion sites, in southern Australia and Tanzania over a 16 year period.

The effects of the MPAs are interesting: biomass of large predators is on a steep increasing trend, while prey-species such as grazing molluscs and urchins are on a downward slope. I wonder what this will lead in terms of macroalgal abundances?

Another interesting finding is that

recently declared MPAs across Australia have been systematically located in areas with few fishery resources. Stakeholders with fishing interests presumably lobbied successfully against the “locking up” of exploitable fish stocks in SZs

I’ve stumbled upon many ecologists who tend to think that MPA’s are almost always designated in pristine areas, thus confounding interpretations of whether they are effective, i.e “the protected sites are healthy, not because they’re protected, but because they were healthy in the first place”. Those with more insights into how local resource users think and work will probably disagree on this, and usually claim the contrary, i.e. “people are pretty darn good at maneuvering the MPA-creation process so as not to include their best fishing grounds”. This study provides compelling evidence of the latter:

The abstract summarizes things nicely:

Tasmanian reef communities within ‘‘no-take’’ marine protected areas (MPAs) exhibited direct and indirect ecological changes that increasingly manifested over 16 years, eventually transforming into communities not otherwise present in the regional seascape. Data from 14 temperate and subtropical Australian MPAs further demonstrated that ecological changes continue to develop in MPAs over at least two decades, probably much longer. The continent-scale study additionally showed recently established MPAs to be consistently located at sites with low resource value relative to adjacent fished reference areas. This outcome was presumably generated by sociopolitical pressures and planning processes that aim to systematically avoid locations with valuable resources, potentially compromising biodiversity conservation goals. Locations that were formerly highly fished are needed within MPA networks if the networks are to achieve conservation aims associated with (1) safeguarding all regional habitat types, (2) protecting threatened habitats and species, and (3) providing appropriate reference benchmarks for assessing impacts of fishing. Because of long time lags, the ubiquity of fishing impacts, and the relatively recent establishment of MPAs, the full impact of fishing on coastal reefs has yet to be empirically assessed.

Management effectiveness of the world’s marine fisheries

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UPDATE: Camilo Mora, the lead author of the study, posted a comment about the test of expert opinions.   “I would like to clarify that one of the tests we did in this paper was to compare the expert’s opinions with actual empirical data collected by one of us (i.t. Tony Pitcher). We found that experts’ opinions match very well the reality of the management of each country and if anything the people inquired actually tended to be more positive about the situation (figure 1c in the paper).  The test you refer to that compared the responses of different experts was intended to assess the precision of the data while the comparison of experts’ answers with empirical data was intended to assess their accuracy. – Camilo”

I wanted his clarification to come up in the main blog post.  Ill look at this issue tonight and will comment/reply if appropriate ASAP.  – “Bruno”

journal.pbio.1000131.g004A new paper (Mora et al. 2009) published in the high profile, open access journal PLoS Biology, documents the management effectiveness of the world’s marine fisheries.  The international team based the analysis on questioners filled out by 1,188 fisheries experts.  The experts were asked to assess the current effectiveness of fisheries management around the world.  The study also calculated “probable sustainability of reported catches to determine how management affects fisheries sustainability”.

One neat aspect of the study is that it asked the experts to evaluate a variety of aspects of management effectiveness including capacity to implement regulations.  However, the weakness, in my opinion, is that the study relied on expert opinion, rather than data. The authors argued that the fact that the experts largely agreed with each other was evidence of the correctness of their opinions: “Experts were mostly fisheries managers, university professors, and governmental and nongovernmental researchers. Despite these diverse backgrounds, responses were highly consistent within each country (i.e., where multiple responses were given, 67% of experts chose the same answer to any given question and 27% chose the next closest response”.  To me, this assertion seems dubious at best.   (There are a number of beliefs held by most my coral reef colleagues that are demonstrably false or only weakly supported by empirical science.)

Our survey shows that 7% of all coastal states undergo rigorous scientific assessment for the generation of management policies, 1.4% also have a participatory and transparent processes to convert scientific recommendations into policy, and 0.95% also provide for robust mechanisms to ensure the compliance with regulations; none is also free of the effects of excess fishing capacity, subsidies, or access to foreign fishing. A comparison of fisheries management attributes with the sustainability of reported fisheries catches indicated that the conversion of scientific advice into policy, through a participatory and transparent process, is at the core of achieving fisheries sustainability, regardless of other attributes of the fisheries. Our results illustrate the great vulnerability of the world’s fisheries and the urgent need to meet well-identified guidelines for sustainable management; they also provide a baseline against which future changes can be quantified.

[youtube=http://www.youtube.com/watch?v=MwG3whtgn64&w=560&h=340]

Authors Summary: Global fisheries are in crisis: marine fisheries provide 15% of the animal protein consumed by humans, yet 80% of the world’s fish stocks are either fully exploited, overexploited or have collapsed. Several international initiatives have sought to improve the management of marine fisheries, hoping to reduce the deleterious ecological and socioeconomic consequence of the crisis. Unfortunately, the extent to which countries are improving their management and whether such intervention ensures the sustainability of the fisheries remain unknown. Here, we surveyed 1,188 fisheries experts from every coastal country in the world for information about the effectiveness with which fisheries are being managed, and related those results to an index of the probable sustainability of reported catches. We show that the management of fisheries worldwide is lagging far behind international guidelines recommended to minimize the effects of overexploitation. Only a handful of countries have a robust scientific basis for management recommendations, and transparent and participatory processes to convert those recommendations into policy while also ensuring compliance with regulations. Our study also shows that the conversion of scientific advice into policy, through a participatory and transparent process, is at the core of achieving fisheries sustainability, regardless of other attributes of the fisheries. These results illustrate the benefits of participatory, transparent, and science-based management while highlighting the great vulnerability of the world’s fisheries services.

[youtube=http://www.youtube.com/watch?v=ZaVJRMSm4-o&w=425&h=344]

From the concluding remarks:  “Current projections suggest that total demand for fisheries products is likely to increase by approximately 35 million metric tonnes by 2030… This contrasts sharply with the 20% to 50% reduction in current fishing effort suggested for achieving sustainability, and implies that regulators may face increasing pressures towards unsustainable catch quotas. Given that the demand for fish lies outside the control of conventional fisheries management, other national and international institutions will have to be involved to deal with poverty alleviation and stabilization of the world’s human population (to soften fisheries demand), if pressures on management are to be prevented and sustainability achieved.”

Citation: Mora C. et al. (2009) Management Effectiveness of the World’s Marine Fisheries. PLoS Biol 7(6): e1000131. doi:10.1371/journal.pbio.1000131

Sylvie Earle – living legend and hero for the planet

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http://video.ted.com/assets/player/swf/EmbedPlayer.swf

TED, a nonprofit devoted to ‘Ideas Worth Spreading’ hosts an annual conference bringing together ‘world’s most fascinating thinkers and doers, who are challenged to give the talk of their lives’. I’ve watched quite a few incredible talks (Al Gore, Tierney Thys, & Jane Poynter to name but a few), but the one that stood out for me was the incredible Sylvia Earle, who is due to host a seminar on marine ecology and conservation in Brisbane in August (link). See below for her bio from the TED website:

Why you should listen to her:

Sylvia Earle, called “Her Deepness” by the New Yorker and the New York Times, “Living Legend” by the Library of Congress and “Hero for the Planet” by Time, is an oceanographer, explorer, author and lecturer with a deep commitment to research through personal exploration.

Earle’s work has been at the frontier of deep ocean exploration for four decades. Earle has led more than 50 expeditions worldwide involving more than 6,000 hours underwater. As captain of the first all-female team to live underwater, she and her fellow scientists received a ticker-tape parade and White House reception upon their return to the surface. In 1979, Sylvia Earle walked untethered on the sea floor at a lower depth than any other woman before or since. In the 1980s she started the companies Deep Ocean Engineering and Deep Ocean Technologies with engineer Graham Hawkes to design and build undersea vehicles that allow scientists to work at previously inaccessible depths. In the early 1990s, Dr. Earle served as Chief Scientist of the National Oceanographic and Atmospheric Administration. At present she is explorer-in-residence at the National Geographic Society.

Sylvia Earle is a dedicated advocate for the world’s oceans and the creatures that live in them. Her voice speaks with wonder and amazement at the glory of the oceans and with urgency to awaken the public from its ignorance about the role the oceans plays in all of our lives and the importance of maintaining their health.

“We’ve got to somehow stabilize our connection to nature so that in 50 years from now, 500 years, 5,000 years from now there will still be a wild system and respect for what it takes to sustain us.” – Sylvia Earle

Ocean acidification an ‘underwater catastrophe’

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‘Climate change is turning our seas acidic, academies warn’ – Reuters News, May 31st 2009

Climate change is turning the oceans more acid in a trend that could endanger everything from clams to coral and be irreversible for thousands of years, national science academies said on Monday.

Seventy academies from around the world urged governments meeting in Bonn for climate talks from June 1-12 to take more account of risks to the oceans in a new U.N. treaty for fighting global warming due to be agreed in Copenhagen in December.

“To avoid substantial damage to ocean ecosystems, deep and rapid reductions of carbon dioxide emissions of at least 50 percent (below 1990 levels) by 2050, and much more thereafter, are needed,” the academies said in a joint statement.

The academies said rising amounts of carbon dioxide, the main greenhouse gas emitted mainly by human use of fossil fuels, were being absorbed by the oceans and making it harder for creatures to build protective body parts.

The shift disrupts ocean chemistry and attacks the “building blocks needed by many marine organisms, such as corals and shellfish, to produce their skeletons, shells and other hard structures”, it said.

On some projections, levels of acidification in 80 percent of Arctic seas would be corrosive to clams that are vital to the food web by 2060, it said.

And “coral reefs may be dissolving globally,” it said, if atmospheric levels of carbon dioxide were to rise to 550 parts per million (ppm) from a current 387 ppm. Corals are home to many species of fish.

“These changes in ocean chemistry are irreversible for many thousands of years, and the biological consequences could last much longer,” it said.

The warning was issued by the Inter-Academy Panel, representing science academies of countries from Albania to Zimbabwe and including those of Australia, Britain, France, Japan and the United States.

Martin Rees, president of the Royal Society, the British science academy, said there may be an “underwater catastrophe”.

“The effects will be seen worldwide, threatening food security, reducing coastal protection and damaging the local economies that may be least able to tolerate it,” he said.

The academies’ statement said that, if current rates of carbon emissions continue until 2050, computer models indicate that “the oceans will be more acidic than they have been for tens of millions of years”.

It also urged actions to reduce other pressures on the oceans, such as pollution and over-fishing.

World Ocean Conference (Part III): Climate change to cause wave of refugees

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picture-392ABC Radio,  May 12th 2009: Australian scientists are warning there could be a wave of economic refugees from South-East Asia and the Pacific if climate change is allowed to devastate the Coral Triangle, north of the Australia. Representatives from 70 countries are meeting in Indonesia today to discuss the health of the world’s oceans. Researchers from the University of Queensland will tell them that unchecked global warming could take a terrible toll. From Indonesia in the west to Solomon Islands in the east and the Philippines in the north, this marine environment is one of the most biodiverse regions in the world. More than three quarters of the world’s reef-building coral species and a third of the world’s coral reef fish can be found within these waters.

[audio:https://climateshifts.org/media/ABC.mp3]

(Photograph ‘Dawn Rip-Wave No.2, Atlantic Ocean’ courtesy of Flickr)

Where have all the big fish gone? Part II: A case study from the Florida Keys

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Following on from two great posts by John and Albert on Carribean reef fish decline and coral collapse, I thought it’d be worth posting these visually stunning images from a recent publication by Loren McClenechan, titled “Documenting Loss of Large Trophy Fish from the Florida Keys with Historical Photographs“. Through analysis of historical photographs in the Florida Keys, Loren managed to piece together a convicing history of recreational fishing trends over the past half century. Large fish really were more abundant in bygone days: the average fish size caught in 2007 was a tiny 2.3kg, compared with 19.9kg in 1957, and that the average length of sharks declined by more than 50% in the same period. In this case though, a picture really is worth a thousand words.

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1957

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Early 1980's

2007

2007

Continue reading →

Coral “can’t escape the heat”

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picture-379ARC CoE, 7th May 2009

The world’s corals cannot escape the inevitable impact on them caused by humanity’s carbon emissions.

The warning comes from the eminent scientist who has used coral from the Great Barrier Reef to reveal disturbing changes in the chemistry of the world’s oceans due to human activity.

Professor Malcolm McCulloch, a geochemist with the ARC Centre of Excellence for Coral Reef Studies and Australian National University today receives Australia’s top honour for earth sciences, the Australian Academy of Science’s Jaeger Medal.

“Coral can’t escape the heat,” he says. “Besides the effects of global warming, corals will not be able to avoid the acidification of the oceans, which is a simple and direct consequence of humanity’s interference in the atmosphere. About 40 per cent of the CO2 we release dissolves into the oceans, turning them more acidic.”

Analysis of corals taken from the sea off Cairns revealed an increase in acidity of as much as 0.3 pH units since the start of the industrial age, with most of it occurring in the last 50 years, he explains. If seawater acidifies only a few tenths of pH units further many corals, diatoms and shellfish will be unable to form their skeletons and shells, posing the risk of major extinctions and a threat to marine food chains.

“It’s getting to the point where, besides reducing our carbon emissions humanity is probably going to have to find large-scale ways of actually removing carbon from the atmosphere,” Prof. McCulloch says.

Of the currently raging political debate over carbon trading he states simply “Whatever policy Australia adopts, the outcome must be to reduce our carbon emissions. While they are small in global terms, if we take no action then big emitters like China and India will see that as a justification not to act. It is up to us to show a lead.”

New coral reef blog on the scene

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One of my PhD Students, Siham Afatta, has started a new science blog called ‘Laut & Kita’ (Sea & Us). Siham (a seasoned blogger) is targeting this as one of very few scientific blogs written in Bahasa (the official language of Indonesia), which focuses primarily on marine conservation in Indonesia. I think this is a great effort and great example of the power of blogging – check out the link below.

lautkita

New evidence from coral reefs suggest sea level rise occurs over ecological time scales

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image003Paul Blanchon and his team have uncovered evidence of extremely rapid sealevel rise 121,000 years ago in one of the warm interglacial periods.  Basically by dating coral skeletons at a place called Xcaret (the beautiful place where a fossil Reef lies exposed), Paul was able to document an abrupt reef crest “back stepping” (essentially the reef crest suddenly appearing landward in a very short time).   The abrupt loss of the lower reef crest growth but continued growth between the lower and upper reef crests has allowed these paleobiologist to draw the conclusion that this occurred due to a 2-3 m sea level rise.  What is the big news, is that it happened over decades.  Measurements of the upward growth of some corals at the “ocean surface” occurred at about 36 mm per year!

Paul is scientist who is characterised by rigour and excellence. He is based at Institute of Marine Sciences and Limnology (ICML) of the National Autonomous University of Mexico (UNAM) in Puerto Morelos on the Yucatan Peninsula.  As a paleobiologist, he is interested in how the world has changed over thousands of years.  For a long time now, Paul has been gathering evidence the great ice sheets the world can break up suddenly over very short period of times.  This latest paper is further evidence of the veracity of this idea – follow this link to see the article in Nature.

Editor’s Summary
16 April 2009

An interglacial jump in sea level

The potential for future rapid sea-level rise is perhaps the greatest threat from global warming. But the question of whether recent ice loss from Greenland and Antarctica is the first indication of such a rise is difficult to answer given the limited duration of the instrumental record. New evidence from an exceptionally exposed fossil reef in the Xcaret theme park in Mexico provides a detailed picture of the development of reef terraces, erosion surfaces and sea-level excursions in the region during the last interglacial. A combination of precise uranium-series dating and stratigraphic analysis, together with comparison with coral ages elsewhere, suggests that a sea-level jump of 2 to 3 metres occurred about 121,000 years ago, consistent with an episode of ice-sheet instability towards the end of the last interglacial. On that evidence, sustained rapid ice loss and sea-level rise in the near future are possible.