Tag Archives: coral reefs

Half the Great Barrier Reef has Disappeared

Crown of Thorns Starfish. Image: AIMSDid you hear the depressing news this week that the Great Barrier Reef is declining faster than ever? A study by the Australian Institute of Marine Science found that the GBR has lost half its coral in only 27 years, and the rate of decline has worsened since 2006.  It is now at a coral cover level of 13.8%, and scientists predict we may only have 5% coral cover by 2022.

Whilst nearly half the damage since 1985 was caused by cyclones, 42% was caused by the destructive activity of the coral-eating crown-of-thorns starfish, and 10% by spikes in sea temperature causing widespread bleaching.  Importantly, coral cover could have increased if not for the starfish problem, but outbreaks of them have become ever more common, likely increased by fertiliser and pesticide run-off.

The study says that the reef could recover if the crown-of-thorns starfish numbers were reduced… and climatic conditions were stabilised.  Since the reef is also threatened by ocean acidification (which reduces the ability of coral to form its calcareous skeleton), trying to stabilise at least the local climate could make a huge difference.

Unfortunately, that’s not the only problem facing the Great Barrier Reef.  The ever-expanding coal and LNG industry along the Queensland coast threatens to turn this once pristine environment into a shipping highway, with all the associated risks of pollution, run-off, and oil spills.  UNESCO recently criticised the Australian government for failing to adequately protect the reef, warning that coastal development offered “serious concerns over its long-term conservation”.  The listing of the GBR as a World Heritage Site could be changed to ‘World Heritage Site in danger’ in a matter of months if steps aren’t taken to better protect it.  But the QLD government says they won’t jeopardise the economic future of the state.

Queensland and federal governments have since launched a review to determine how they can better manage the Great Barrier Reef alongside increasing urban and industry development.

Meanwhile, scientists are working on novel ways to protect the reef, and say that improved water quality is certainly key.

Queensland MP Bob Katter wants to put a bounty on the crown-of-thorns starfish… But the Environment Minister says that research and government-assisted culling is the way to go.  (The starfish’s spines are poisonous by the way… I know I wouldn’t dive for them!)

Green groups such as Greenpeace, the Australian Marine Conservation Society, WWF, the Australian Conservation Foundation and many others have ongoing campaigns aimed at raising awareness of the reef’s plight, trying to stop the destructive development plans along the coast, and improving water quality.  If you are concerned or want to learn more, I suggest heading over to their websites to sign up your support.

It would be Australia’s greatest shame to lose the Great Barrier Reef.  But if we don’t act now, that day is fast approaching.




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Ocean-based food security threatened in a high CO2 world

This month, Oceana released a document entitled ‘Ocean-Based Food Security Threatened in a High CO2 World: A Ranking of Nations’ Vulnerability to Climate Change and Ocean Acidification’.

I urge you to have a read [PDF – 1.06MB] .

The report outlines the seafood security problems that the world will face due to human-induced climate change, and offers a ranking of vulnerability by nation as a result.

Changes in ocean productivity will affect billions of people around the world who rely on seafood for their livelihoods and diet.  Some nations may be better able to cope with these changes than others, but none can escape them.  The report ranks nations based on the seafood security hardships they may experience.  The results are sometimes surprising… And certainly food for thought.

The Two Main Factors Considered

As the pH of the ocean becomes more acidic (due to absorption of CO2 from the atmosphere), coral reef systems and hard-shelled molluscs will be less able to cope.  They need a mineral called aragonite to make their skeleton, which is less available in more acidic waters.  Coral reefs support about a quarter of all marine fish species; people around the world depend on these fish as a stable source of protein.  Shellfish such as oysters, clams and abalone may also be significantly affected, which could impact many jobs, but more importantly some nations rely on them for 50% or more of their protein.

The second issue is that climate change will change ocean temperatures.  This is likely to affect ocean circulation, which will in turn affect nutrient availability, an effect which which will be felt throughout the food chain.  Studies have shown that marine fish and invertebrates tend to shift towards the poles and into deeper waters when temperatures rise.  Using a recent model, the report showed how fisheries catch potential could change around the world as a result of rising ocean temperatures – leading to a loss of up to 40% catch potential in the tropics.  This could be very bad for nations without a strong economy or large industrialised fishing fleets, since they will be unable to follow the shifting resources.

Shifting Fisheries Catch Potential Due to Rising Ocean Temperatures by 2055 Threatens Seafood Security. Adapted from Cheung et al. 2010. Figure from Oceana

Shifting Fisheries Catch Potential Due to Rising Ocean Temperatures by 2055 Threatens Seafood Security. Adapted from Cheung et al. 2010. Figure from Oceana

In order to calculate vulnerability to seafood changes, the report looked at the predicted effects caused by the above changes, and how they would impact each country.  This was combined with how dependent the country is on seafood consumption, i.e. the percentage of fish and seafood consumed per capita compared to other animal protein.  This is also linked to availability and price. For example, fish can be the cheapest and most available source of animal protein in some developing countries, and the highest seafood consumption per capita usually occurs in coastal and island nations serviced by small scale fisheries.  Both these types of countries would be highly vulnerable to changes in fisheries catch potential and distribution.

Adaptive capacity can also be measured via gross domestic product (GDP) per capita.  This shows the extent of economic resources available per person; a higher GDP per capita is assumed to mean that a nation could more easily develop or import more food to compensate in seafood protein losses.  Such nations are less vulnerable to the predicted changes.

Nations with a high population growth rate will have a higher growing demand for protein sources, thereby increasing their vulnerability to protein losses.  And some nations already have problems feeding their populations.  Countries with an undernourished population (>5% of the population undernourished) will be more likely to experience food security issues due to a loss in seafood protein.

The Ranking

The report ranked nations in order of how vulnerable they were to threats from climate change and ocean acidification in terms of seafood security, considering each independently and then combined.

Most Vulnerable Nations to Food Security Threats Due to Climate Change and Ocean Acidification. Source: Oceana

Combined Vulnerability - Top 25 Nations. Source: Oceana


The rankings show that coastal and small island developing nations are vulnerability hotspots for individual and combined effects of climate change on the oceans.  This is especially true for low latitude, tropical countries, where species may undergo migration and coral reef fisheries could be threatened, and island nations that depend on fish for protein.

Nations with rapidly growing populations which provide significant subsidies to their oil and gas industries – such as Iran, Libya, and the UAE – are also ranked at high potential food security risk from loss of seafood catch potential.  They could become more dependent on food imports, and loss of fisheries would have serious impacts for some of the poorest artisanal fishermen in these oil-producing countries.

Shifting from wild-caught seafood to imported, processed foods may also lead to health problems such as diabetes, a problem which has been shown in the Pacific Island nations recently.  Harmful bacteria in shellfish which cause disease in humans can also increase as ocean temperatures rise.

And there are other issues to consider.  Seafood for the diet is one thing, but millions of fishermen also rely on seafood for their livelihoods.  Marine tourism is a multi-billion dollar industry – which could be threatened due to climate change and its impacts on coral reefs and marine life.  Not to mention the aquarium export industry, and the increasing use of the marine environment for aquaculture.  Changes to local marine resources could ‘ripple up’ through the global economy.

So What Can We Do?

As always, Don’t Despair!

This report was a little scary but also good to have – with it we can target places that are particularly vulnerable and help them adapt to the issues caused by future climate change.

Oceana suggests that the best things we can do are to reduce CO2 emissions; end fossil fuel subsidies to help transition to renewable energy; stop overfishing, bycatch and destructive fishing practices; establish marine protected areas; and manage fisheries for change.  This can help us become more resilient to climate change and future impacts.

Personally, I don’t eat seafood at all, thereby reducing my own individual burden on the world’s fisheries.  It’s a personal choice, but I don’t expect everyone to be that drastic.  If you choose sustainable fisheries, and try to make a choice about where your food is coming from, you’ll be making a big difference.  And maybe spare a thought for the billions of people who really do rely on fish for protein.

Together we can work towards a a sustainable future, in a world in which no-one goes hungry.

What Do You Think?

I’d love to hear about your own opinions on how we can better manage fisheries to cope with the problems caused by climate change.  Is your country one of those listed as particularly vulnerable to the effects?  There are many problems surrounding global fisheries management, climate change is just one of them.  What do you think are the most important issues to consider in order to have a more sustainable food future?

If you’d like to read the report, click here for the PDF link (1.06MB).

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