Are marine fishes important to our survival?
'Look at agriculture - we're running out of land, we're running out of water. Look how the prices of food are going up. In the future, people's protein is going to have to come out of the sea - it's all we have left.'
Read more about this issue in Is farmed fish the new battery chicken? and the fishing industry's latest can of worms by Alex Renton, The Observer 24 Feb 08.
But at the same time "A deadly combination of climate change, over-fishing and pollution could cause the collapse of commercial fish stocks worldwide within decades" U.N. says world fisheries face collapse on Reuters 22 Feb 08;
While reefs are devastated for short-term gains Sri Lanka coral reef fisheries destroyed by organized crime: officials from the Lanka Business Online 23 Feb 08.
And buyers are not supporting Indonesian eco-friendly reef fish by Dicky Christanto, The Jakarta Post 18 Feb 08;
Land based activities also affect our seas: Rainforest logging threatens endangered sea turtles by Rhett A. Butler, mongabay.com 25 Feb 08.
Killing sharks hurts the reefs: "ecosystems which are dominated by large predators like sharks and groupers, and corals there are robust, while the most populated atolls, are characterized by fleshy algae, small plankton-eating fish and degraded corals" in Coral Reefs and What Ruins Them by Cornelia Dean, New York Times 26 Feb 08.
And pollution kills reefs: Caribbean Sea one of world's most polluted by Aretha Welch Trinidad&Tobago Express 23 Feb 08.
As well as seagrasses: Seagrass study calls for chemical cuts on ABC News 26 Feb 08.
Plastics never go away: Microplastics in remote sea: marine pollution at worse levels than thought by Chris Baker, The Guardian 27 Feb 08.
and continues to kill: Senseless, agonising death of a gentle giant by Rebekah Cavanagh, Northern Territory News 27 Feb 08
even whales! 2lb of plastic poison found in whale's stomach The Daily Mail 27 Feb 08;
Will we lose our marine life species by species? Butterflyfish may go extinct by ARC Centre of Excellence for Coral Reef Studies, Science Alert 25 Feb 08.
While climate change affects the oceans
Too cold: Tons of dead fish wash up on Taiwan beaches due to cold temperatures on Reuters 22 Feb 08.
Too hot: Watching Peru's Warming Oceans for Cholera Cues by Joanne Silberner, NPR 26 Feb 08.
Too dead: Ocean ‘desert’ zone extends to isles by Helen Altonn, Honolulu Star Bulletin 25 Feb 08.
But there are signs of positive action!
Action by individuals: Local man leads mangrove tours in Bali by Irawaty Wardany, The Jakarta Post 27 Feb 08.
As well as civil society: Jakarta Green Monster protects wetlands in The Jakarta Post 24 Feb 08.
And government action to stop senseless killing Law to get rid of ‘ghost traps’ paying off by Marty Schladen, The Daily News, Galveston County 23 Feb 08.
And can the shores take us?
"There is probably no hope for those teachers and counselors who stand placidly by while robust, undirected adolescents throw sea urchins at each other or stomp the gumboat chiton to death"
The budak blog explores the magical moments on the intertidal as well as the issues impacting our shores.
Ria shared about our reefs and shores to about 40 people of the NIE Green Club.
The group included Prof Er Meng Hwa, Deputy President of Nanyang Technological University who was the Guest of Honour, and NIE senior officers.
After the talk, Ria had lots of engaging conversations with participants for more activities for our shores and reefs! Fantastic!
Thanks Vilma D'Rozario and the NIE Green Club for organising the talk on 22 Feb (Thu)! More about the talk on the NIE Green Club blog with a lovely list of more things you can do for our shores and reefs.
There are marvelous sea legends associated with Kusu Island. Most revolve around tales of a miraculous rescue from disaster at sea, a giant turtle and the friendship of two men, one Malay and the other Chinese.
Some of the stories listed in the Singapore infopedia website of the National Library include these:
Legend has it that during the 9th lunar month in the Chinese calendar, a huge turtle saved a group of sailors from rough seas by turning itself into an island. The grateful sailors returned there the following year to make offerings of thanksgiving and the island has thereafter been treated as sacrosanct and has become a place of worship. (Prior to reclamation, it is said that Kusu Island resembled a sea turtle.)
Another tale is of an Arab named Syed Abdul Rahman who left Singapore with his wife and daughter on a journey in search of peace. Caught in a violent storm their sampan capsized. Lost in the open sea, a giant tortoise spotted them and brought them back to safety. They were beached at an unknown island which, from a distance, bore the silhouette of a turtle. Beside them, they found not only their lost sampan but food in it.
A traditional tale includes that of a sailing boat that foundered near Kusu Island and went down in strong waves. Two survivors, a Chinese and a Malay, swam ashore. Stranded on the island, they lived on shrubs and wild shoots. Their good friendship lasted until they died. Years later, when a ship contaminated by an epidemic dropped anchor near the island, the scourge miraculously disappeared and the sick regained good health.
About 170 years ago, two holy men, Dato Syed Rahman, an Arab, and Yam a Chinese, meditated and fasted on their pilgrimage to Kusu. Yam fell ill and Syed prayed fervently for him. The sudden appearance of a boat with food and water saved both their lives. As time lapsed, the two men regularly visited Kusu to offer thanksgiving. When they died, they were buried next to one another on the island. Later the Tua Peh Kong Temple and the Malay shrine were erected and dedicated to their memory.
Kusu means "Tortoise Island" in Chinese. And turtles are a major a feature at the Kusu Island temple, with turtle icons everywhere.
There are also sculptures of land tortoises (oops).
And a small pond of 'released' land tortoises and freshwater turtles, which unfortunately is a rather sad sight.
In the large brackish water pond next to the temple, one or two sea turtles were seen in the past.
Unfortunately, the temple people are not very marine-friendly. On a trip this month, volunteers encountered large fish traps laid out on the Kusu shore by the temple residents.
More about Kusu Island
'Southern Haunt' exploded the myths that there is little life left in Singapore murky waters, or that diving is even possible!
On 15 Feb, about 50 students were treated to Debby Ng's stories about Pulau Hantu's underwater beauty and the threats it faces, while Toh Chay Hoon also shared about all our other wildlife beneath the sky - from spiders and lizards to slugs and bugs!
From their reactions and bizarre questions, it was apparent the students were intrigued and astonished.
See Pulau Hantu for yourself and join the Hantu Bloggers for their Anniversary Dive including a night dive on 23 Mar (Sun).
More about the talk, Pulau Hantu and how to join the Hantu Blgogers on the Hantu Blog.
Want the Hantu Bloggers to share their talk with your community or work group? Here's more details on reef talks offered by Debby and other speakers as part of the International Year of the Reef celebrations.
Sea turtles are still seen our shores. The photo is of one seen near on Nov 07 near Pulau Semakau.
Sea turtles, however, are in dire straits.
On nearby Trengganu shores, originally famous for their sea turtle sightings, only dead turtles are washing up. They were killed by fishermen's nets.
Thousands of sea turtles washed up on the Orissa shores, also killed by fishermen activities. Dead sea turtles are also washing up on shores in the UK.
Besides fishermen, sea turtles are also killed by when they eat plastic bags, which they mistake for their natural jellyfish prey. There is also some concern that overharvesting of jellyfish for the seafood trade are starving sea turtles.
The loss of sea turtles is one of the factors thought to have caused the explosive growth of toxic jellyfishes in the Mediterranean where they plague tourists at the sea shore.
There are some positive signs.
A recent study shows conservation of nesting sites can allow a recovery of sea turtle populations.
The SEE turtle project was recently launched to raise awareness of the plight of these magnificent animals.
In the Philippines, conservation efforts have converted former dynamite fishermen into protectors of sea turtles and marine life.
Cuba recently banned the hunting of sea turtles, while some in some US cities, there are new rules to dim lights on the shores to avoid disturbing nesting sea turtles.
Nearer home, read more about initiatives to protect sea turtles in the peninsula in the Sea Turtle Specials on the wildasia website. Learn more about hawksbills in the peninsula, sea turtle conservation in Malaysia with fact sheets about our sea turtles and the major threats to them, and more about saving our sea turtles and what you can do to conserve them.
You CAN make a difference for our sea turtles
A new series on Arts Central airs on 19 Feb (Tue) at 9.30pm.
Learn more about our shores as Shawn Lum and co-host Sue-Lyn kick off the first episode with a look at the Marina Barrage and Kusu Island.
"After a successful first series exploring our natural heritage and learning the importance of forest trees and their intrinsic values, Once Upon a Tree returns to the screen again, this time turning its attention to our waters.
The Sea is a proverbial window to the rest of the world. It was also what brought commerce, stories, culture and life to our island. Its this theme of "together-ness" that will be our main focal point in the first episode.
What similarities does a research doctor have in common with a retiree? Host Dr. Shawn Lum finds out. Shawn also explores the abundant marine life found along our financial hub and speaks to an engineer behind the Marina Barrage. A construction that will affect both humans and the inhabitants of the water.
Co-host Sue-Lyn is off to investigate the inter-tidal habitats of Kusu Island with guest expert Yu-Chen. What will they find in the muddy waters? Find out in Once Upon a Tree - Tides & Coastlines."
Time: 9.30pm Arts Central
What do people think about this first episode?
Here's Jun's super instantly-posted review on her Ashira blog
Kusu Island, like many of our Southern Islands, played its part in the history of the mainland Singapore.
From the Singapore infopedia website of the National Library ...
The earliest mention of Kusu Reef was in the 17th century. Dom Jose de Silva, Spanish Governor of the Philippines was believed to have run aground on March 1616 at Kusu Reef and thus the coral island had gained the name "Governor's Island" which was later adopted by the Singapore Straits which became known as the "Governor's Straits".
In 1806, the island gained the name "Goa Island" given by the East India Company hydrographer, James Horsburgh.
With the founding of Singapore, Daniel Ross, hydrographer to Stamford Raffles, selected the island in 1819 as a reference point for ships entering the new harbour. The earliest charting of the island is in Lt. Jackson's Chart of 1822. The signal flagstaff of the station manned by the Harbour Master's Department was set up on the little island when it was still known as Goa Island or colloquially, Pulo Tambakul.
The island was the burial site for immigrants who died in quarantine on St. John's and Lazarus Islands.
Kusu Island was originally largely made up of living reef. Submerged reefs are indicated by the dotted portions in the map below of P. Tembakul, one of the old names of Kusu Island.
How amazing the shores must have been then!
In 1900-1930, the temple on Kusu Island was surrounded by water at high tide. Kusu Island is also known as 'Turtle Island'. Some accounts say that the island originally comprised two portions which resembled a sea turtle with a larger part resembling the shell and a smaller portion the turtle's head emerging from the sea.
Kusu Island was originally 1.2 ha.
In 1975, there was massive reclamation "to join it with another coral outcrop, making a 8.5ha island resort".
This is what Kusu Island looks like today, with two swimming lagoons and jetties.
But corals are returning to Kusu, growing into the swimming lagoon...And outside the seawalls as well ...We have lost much reefs at Kusu Island, but there are still rich reefs there. You can see the reefs without having to dive or swim! Just join the Blue Water Volunteers in their Kusu Reefwalk.
More about Kusu Island
A microcosm of multi-cultural Singapore, Kusu Island has an enchanting blend of religious significances. Kusu Island today remains the destination of an annual pilgrimage of up to 100,000 people! There is both a Chinese temple and Malay shrines on the island.
The most engaging description of the shrines of Kusu Island is found on infopedia of the National Library website.
"Every year, on the 9th day of the 9th moon in the Chinese calendar, a month-long festival stretching between September to November see more than 100,000 devout Taoist, Buddhist, and Confucian pilgrims visit Kusu Island.
The island houses a Chinese temple and three Malay Keramats.
The Chinese temple was built by contributions from a Chia Cheng Ho in 1923 who initiated the worship of Tua Peh Kong (earlier known as Da Bo Gong), the "Merchant God" or "God of Prosperity". Guan Yin, the "Goddess of Mercy" and the "Giver of Sons" is also prayed to there.
At least, 80% of the devotees are women, many praying for good husbands, healthy babies and obedient children. At least five blessings are sought for: longevity, wealth, tranquility, love of virtue and a fulfilled destiny.
Devotees also climb the 152 steps to reach the Malay shrines. One of the shrines is dedicated to Syed Abdul Rahman, whilst the other two are believed to belong to his mother, Nenek Ghalib and his sister, Puteri Fatimah Shariffah. The shrines are watched over daily by Pak Ali, who tends to the Keramat Datok Kong and Haji Shamsudin who tends to the Keramat Datok Mother and Keramat Datok Daughter, as they are named.
Placards next to the later two Keramat seem to indicate that Nenek Ghalib had visited a Baba Hoe Beng Huat and garnered finances to build these shrines from this group of Peranakans some time in 1917."
A sign near the Chinese Temple also reveals these details ...
The popular cult of Da Bo Gong (The Merchange God or God of Prosperity) found its fruition on Kusu in 1923, when a wealthy businessman, identified on a stone slab as Chia Cheng Ho, donated money for the building of the temple in honour of the Merchant God.
The Chinese Temple houses many deities, but the two main deities are the Da Bo Gong and Guan Yin.
Da Bo Gong is highly regarded as having the power to confer prosperity, cure disease, calm the sea and avert danger. Guan Yin (Goddess of Mercy) is surnamed Sung-Tzu-Niang-Niang and also known as the 'Giver of Sons".
In their prayers, devotees usually request for five blessings from the Gods, namely: Longevity, Wealth, Tranquility (Health of body as well as peace of mind), Love of Virtue and Fulfilled Destiny.
According to the Sentosa website, the Malays shrines are also popular with childless couples who would pray for children.
It is said that petitioners will tie a ribbon on trees near the shrine. And indeed the trees near the bright yellow shrine are festooned with ribbons.The annual pilgrimage accounts for this strange sight on the island!
The area is totally empty of course, except during the pilgrimage season, when the island is truly bustling with people.
In the past, the temple of Kusu Island was on the water! As shown in the photo below...
In the next article, more about the history of Kusu Island.
More about Kusu Island
Coral reefs, seagrass beds, mangroves, rocky reefs and shelves are among the most seriously altered ecosystems.
Here's some excerpts...
Full articles on the wildsingapore news blog
No areas of the world's oceans remain completely untouched by humanity's influence, according to a new study.
Every area of the oceans is feeling the effects of fishing, pollution, or human-caused global warming, the study says, and some regions are being affected by all of these factors and more.
Of all the human effects on marine ecosystems, climate change is having by far the largest overall impact, the researchers estimate.
Greenhouse gases such as carbon dioxide are warming up the atmosphere and, more slowly, the oceans. Also, carbon dioxide dissolves into ocean waters, turning them more acidic, which makes it harder for corals, shellfish, and other animals to grow their protective skeletons or shells.
Reefs and mangroves, coastal habitats that receive a lot of attention from conservationists, were heavily damaged by human activities, the study said. Worst were rocky reefs and continental shelves, where commercial fishing concentrates.
Is it really that bad?
The team did not measure the effects of certain practices, such as illegal fishing and aquaculture, the farming of aquatic plants and animals.
"This makes their estimates of habitat decline conservative, and things are probably worse than they outline,"
"These human impacts overlap in space and time, and in far too many cases the magnitude is frighteningly high," he said.
What can be done about it?
The study "highlights the fact that ecosystems in the sea know no political boundaries. Hence an international, cooperative approach is the only way forward."
"The message for policymakers seems clear to me: conservation action that cuts across the whole set of human impacts is needed now in many places around the globe."
Policy makers should use the scientists' map to separate harmful ocean activities, so negative effects aren't magnified, Halpern said.
"We have business districts and residential districts, schools and churches. All these things are zoned into different places to create some cohesion to our communities that make sense. You don't have a strip club next to a school," the researcher said. "We can allow all these activities to go on, but just not in the same place."
What can you do about it?
Stop being a part of a problem
Start being a part of the solution
More on what you can do to make a difference.
Did you know that this is the most numerous bird on Singapore's shores?
And did you know that this bird has two different kinds of plumage? One in dull 'winter coat' and a more dashing one in 'summer'?
Singapore Changi Airport is well known as the No. 1 for air travel. But did you know that our shores are also a key stop over for the marvellous birds that fly from Siberia to Australia and New Zealand every year?
These amazing birds rely on the shores as refuelling stops on their grueling journeys.
Budak shares a special feature especially for the International Year of the Reef 2008, with fascinating details about the bewildering variety of shorebirds that visit Singapore every year.
From herons to ducks, plovers to pipers, eagles to egrets, learn more about how so many different shorebirds can feed off the same shore. He also shares some of the many perils that threaten them.
More on his annotated budak blog with links to amazing photos on his flickr set of birds.
You CAN make a difference for our shores birds
Learn more about them by visiting our shores. The Sungei Buloh Wetland Reserve has lots of information, facilities and knowledgeable guides who can share all about these birds.
Share what you observe or find out. The bird ecology study group has an excellent blog which features behaviour and observations by ordinary people of our birds. Infact, there just this instant an entry about a new Plover observed for Singapore and Malaysia.
The Hantu Blog celebrates its fourth birthday! To commemorate four years of great diving, they will be doing 4 dives which includes a night dive.
Register now for this unique and educational dive experience in our local waters. Discover what is truly, uniquely Singapore!
Organised by the Hantu Bloggers. Here's a slideshow of sightings on the last Annniversary Dive.
Join the The Hantu Bloggers Yahoo Group to read the trip itinerary, and to be informed of future dives.
Pre-registration is required. More details on the Hantu Blog.
Less than 6km from the city centre and 15 minutes by speedboat are living reefs on little Kusu Island!
At high tide, white reclaimed sand rings the swimming lagoons. Where city folks and their families can take a break.
But as the tide goes out, the wonderful marine life right in the lagoon is revealed!
The Blue Water Volunteers conduct guided reefwalks so ordinary people can explore our very own wild reefs. No need to swim, no need to dive!
And what can you see? Corals of course! Also sea stars, fishes, crabs, slugs and more. Sam shares on his ramblings of a peculiar nature blog what he and his friends saw on their first visit to Kusu Island just last week!
When the tide is REALLY low, and we are lucky, we might get to see 'Nemo', our very own clown anemonefishes, happily swimming among the anemones on the shore.
MORE blog entries about trips to Kusu Island, and MORE photos of marine life on Kusu Island.
The reefs of Kusu Island are also spectacular underwater!
The Blue Water Volunteers saw this underwater garden when they conducted the reef survey at Kusu Island on Jun 07! Minsheng took the photo.
This fantastic pink feather star was among the sightings during a Kusu dive in Nov 07, shared on the colourful clouds blog. And MORE photos of Kusu underwater on Pocillopora's flickr set.
Kusu Island is better known for its Chinese temple. Although few realise it lies next to equally fabulous shores...
More in upcoming articles, about the legends and shrines on this tiny but fascinating island.
The world's rubbish dump: a garbage tip that stretches from Hawaii to Japan
Kathy Marks and Daniel Howden, The Independent 5 Feb 08;
A "plastic soup" of waste floating in the Pacific Ocean is growing at an alarming rate and now covers an area twice the size of the continental United States, scientists have said.
How about Singapore? Do we have a plastic pollution problem?
First some excerpts about the global situation...
"The vast expanse of debris – in effect the world's largest rubbish dump – is held in place by swirling underwater currents. This drifting "soup" stretches from about 500 nautical miles off the Californian coast, across the northern Pacific, past Hawaii and almost as far as Japan."
"About one-fifth of the junk – which includes everything from footballs and kayaks to Lego blocks and carrier bags – is thrown off ships or oil platforms. The rest comes from land."
"Warning: Unless consumers cut back on their use of disposable plastics, the plastic stew would double in size over the next decade."
"Modern plastics are so durable that objects half-a-century old have been found in the north Pacific dump. Every little piece of plastic manufactured in the past 50 years that made it into the ocean is still out there somewhere."
"According to the UN Environment Programme, plastic debris causes the deaths of more than a million seabirds every year, as well as more than 100,000 marine mammals. Syringes, cigarette lighters and toothbrushes have been found inside the stomachs of dead seabirds, which mistake them for food."
"Plastic is believed to constitute 90 per cent of all rubbish floating in the oceans. The UN Environment Programme estimated in 2006 that every square mile of ocean contains 46,000 pieces of floating plastic."
The full article is on wildsingapore news.
And the situation in Singapore?
From K. L. Ng & J. P. Obbard, 2006. Prevalence of microplastics in Singapore’s coastal marine environment. Marine Pollution Bulletin, 52(7): 761-767.
"Microplastics have been recently identified as marine pollutants of significant concern due to their persistence, ubiquity and potential to act as vectors for the transfer and exposure of persistent organic pollutants to marine organisms. This study documents, for the first time, the presence and abundance of microplastics (>1.6 μm) in Singapore’s coastal environment."
"The presence of microplastics in sediments and seawater is likely due to on-going waste disposal practices from industries and recreational activities, and discharge from shipping."
Read more on “Prevalence of microplastics in Singapore’s coastal marine environment.” on the News from the International Coastal Cleanup Singapore blog
You CAN make a difference!
Amazing sighting today shared by Jun on her ashira blog
She shares: "Just as I was getting back on the boat, the boatmen went "Dolphin dolphin!" And lo and behold, there they were. 3-4 of them grey ones (think probably bottlenoses) were breaching every once in a while as they went with the currents". She also added "the boatmen keep telling us they spot the dolphins regularly".
Wow! It's exciting to know we still have these wild magnificent animals on our reefs!
List of previous sightings in our waters compiled on wildsingapore.
Here's some latest news wild dolphins in general ...
103 whales, dolphins and dugong found dead in Queensland, 2006
Humans to blame for sealife toll
Brian Williams, couriermail.com.au 31 Jan 08;
Dolphin hunt sags amid mercury fears
Joseph Coleman, Associated Press Yahoo News 30 Jan 08;
Bangladesh's majestic dolphins at risk
Alastair Lawson, BBC News 28 Jan 08;
'Tougher laws' to protect friendly dolphins
Brian Unwin, The Telegraph 22 Jan 08;
more of the latest news about dolphins on the wildsingapore news blog
Share YOUR favourite photo of Singapore's reefs and shores!
Join the public IYOR Singapore flickr group!
Already uploaded, several high res photos for use by those who want to write articles about our reefs and shores.
The group is also open to anyone who wants to contribute their photos.
Come celebrate our reefs!
IYOR just came across this notice on the Pasir Ris NParks website: "This cute fella was spotted by one of our staff at Sungei Tampines earlier this month! A rare sight indeed."
Wow! That's a great sighting indeed!
On World Wetland Day, a quick run through of recent media reports about rising sea levels and the role of wetlands and our coastal ecosystems in flood mitigation.
Will sea levels rise?
"Six of the 10 experts contacted by Reuters in the last 10 days stuck to projections by the UN Climate Panel that sea levels will rise by between about 20 and 80 cms by 2100."
from Latest Scientists' Views of Sea Level Rise PlanetArk 1 Feb 08;
see also Rising Seas: how much will waters rise and what drives them up? Mark Kinver, BBC News 22 Jan 08;
"Even if a fraction melted, Antarctica could damage nations from Bangladesh to Tuvalu in the Pacific and cities from Shanghai to New York"
from Antarctic ice riddle keeps sea-level secrets Alister Doyle, Reuters 30 Jan 08;
"Gilbert Adikpeto remembers the night he lost much of his shorefront home, literally washed away by the sea. We were asleep with the children when there was a deafening noise from the living room. I got up in a panic and the whole room had disappeared under the waves"
from Cotonou - a city slowly swallowed by waves Independent Online 25 Jan 08;
What is role of wetlands in flood mitigation?
"Recreating wetlands and restoring peat bogs and free-flowing rivers could dramatically reduce the risk of flooding"
from Restoring wetlands in the UK 'reduces flood risk' The Telegraph 30 Jan 08;
"The government also said it would invest in a project studying how best to use the ecosystem, such as natural sand flows, for flood protection"
from Dutch to explore new ways to defend coastline Reuters 1 Feb 08;
What is the current state of our wetlands?
"The world has lost around 3.6 million hectares (8.9 million acres) of mangroves since 1980, equivalent to an alarming 20 percent loss of total mangrove area"
from FAO warns of 'alarming' loss of mangroves Yahoo News 1 Feb 08;
Wetlands are part of the spectrum of ecosystems that include the reefs.
World Wetlands Day marks the date of the signing of the Convention on Wetlands on 2 February 1971, in the Iranian city of Ramsar on the shores of the Caspian Sea. It is run by The Ramsar Convention on Wetlands.
What do wetlands do for us?
Why should Singaporeans care?
Destruction of wetlands around us affect us too.
Here's an extract from the World Wetlands Day website
Adequate, good quality food is a prerequisite for healthy people, and wetlands are key contributors, supplying us with, for example, fish (including shellfish), and plants (including fruits, seeds, as well as the vegetative parts). One billion people rely on fish as their main or sole source of protein and many more consume fish regularly. In terms of cultivated wetland plants, rice is the most important at a global level, providing 20% of the world's dietary energy supply. Other wetland plants, such as seaweeds, although not harvested on the same scale as fish, are still an important source of food for local use and for international markets. Indirectly, wetland plants often play a vital role as a food for livestock on which the health of billions of people depend.
Well managed, our wetlands will continue to provide food to keep us healthy - but there are many human actions that negatively affect the capacity of wetlands to continue to provide for us. Pollution, excessive water abstraction, poor sanitation, overharvesting and, of course, wetland destruction, all reduce or destroy the capacity of wetlands to provide food for human consumption.
We've been saying it for years - inland wetlands (rivers, lakes, ponds, marshes, etc.) perform a vital function in filtering and purifying freshwater, rendering it 'clean' for human consumption. And never has it been a more valuable service for human populations than today when over one billion people lack access to clean water supplies. But wetlands can only provide us with clean water if we keep them healthy through effective management. What happens when we destroy our wetlands is obvious - we lose this source of clean water, as well as all the other ecosystem services they provide. And what happens to our clean water supply when we add too many human by-products to wetlands? . . . Find out more in our section on pollution.
Despite the capacity of freshwater wetlands in purifying water, they do have their limits. They can only deal with so much agricultural runoff, so much inflow from domestic and industrial wastes. And of course the human species is capable of adding much more - toxic chemicals (such as PCBs, DDT and dioxins), antibiotics from animal husbandry, untreated human sewage, pesticides that act as 'endocrine disrupters' . . . and more. We can, and do, readily move beyond the purifying powers of wetlands so that these sources of freshwater, and the food they supply, are rendered unfit for consumption and a danger to human health.
Of particular concern are the 2.6 billion people today who lack access to adequate sanitation. Poor sanitation adds to the microbial contamination of drinking water provided by wetlands - and then to sickness and sometimes loss of life.
Wetlands act as filters or traps for many pathogens - when the passage of water through wetlands is long enough, pathogens lose their viability or are consumed by other organisms. Human-made wetlands are being constructed in urban and rural areas to perform just this function and thus prevent untreated sewage reaching natural wetlands that are used as an immediate source of drinking water.
In many parts of the world, human health is closely linked to water-related diseases. Malaria, because mosquitoes breed in wetlands, and diarrheal infections (including cholera) because of sewage contamination are globally the worst in terms of their severity of impact, accounting for 1.3 and 1.8 million deaths respectively in 2002, and affecting the health of many, many more. Fatalities are almost entirely in children under 5 years of age. Diarrheal diseases affect both African and south Asian countries, whereas malaria's impact is largely in Africa but also significant in many parts of Asia and the Americas.
While malaria and diarrheal diseases are the two worst in terms of human impact, we might add to this the debilitating effects of other wetland-related diseases such as schistosomiases, Japanese encephalitis, filariases, onchocerciasis and others.
Diarrheal diseases can be controlled through provision of clean water, good sanitation practices and hygiene education. Poorly treated human sewage contains pathogens that are a key cause of diarrheal infections - and wetlands (both inland and coastal) can be an important transport mechanism for such pathogens where sanitation is poor.
Controlling malaria was one of the driving forces for wetland destruction in the past, especially in Europe, but this has led to the loss of vital ecosystem services such as water and food and is not considered an option today. Solutions that are working, at least in some areas, range from the use of fish that consume the mosquito larvae and bacterial larvicides that kill them without affecting other organisms, to better design, management, and regulation of dams and irrigation schemes and water drainage systems that can reduce breeding sites.
Floods and storms have affected human lives since the beginning of civilization, but all types of floods - riverine and coastal floods and storms, sudden snow melts, floods after intense rainfall - have become more destructive in recent decades, because increasingly human infrastructure is being built in flood-prone areas, and they are likely to be even more pronounced in the future. This we are all aware of from the international media, from statisticians, and perhaps from our own personal experiences.
The direct and immediate impacts on human health include loss of life, injuries, and, within a very short period of time, the lack of clean water and destruction of sewage systems, which result in another set of threats to human health - diarrhea, cholera, and other life-threatening, water-related ailments. Receding floods in some countries also provide the perfect environment for malaria-carrying mosquitoes. Finally, there are the longer term effects on mental health, such as anxiety and depression that often follow a major flooding event.
While we cannot easily prevent major floods, we can ensure that we benefit from the flood protection services that wetlands supply free of charge. Rivers, lakes and marshes slow down and retain floodwaters but only if we do not build our urban centres on natural floodplains and are more thoughtful about the broader implications of channellising our rivers and draining our marshes.
Controlled burning has been used effectively in peatland management in various parts of the world, but events in recent years in southeast Asia have highlighted the fact that extensive and uncontrolled burning can have serious direct effects on human health. For example, the largely deliberate burning for land-clearing in 1997-1998 in southeast Asian peatlands affected around 70 million people with around 12 million people requiring health care for respiratory problems. Significant burning events since then have continued to affect the health of large numbers of people.
In the longer term, peatland burning and drainage activities have led to massive increases in the emissions of greenhouse gases, contributing to climate change, and these activities have often destroyed local livelihoods as well.
If water is extracted more rapidly than it is naturally replenished, wetland ecosystems will, in extreme cases, collapse, with a complete loss of ecosystem services. The effect of such extreme cases is costly in terms of human health. A well-documented example is the Aral Sea where water abstraction for irrigating crops reduced a vibrant wetland to dust - causing loss of livelihoods in the short term and, in the longer term, seriously impairing the health of communities that lived around the sea through the health effects of dust storms, erosion, and poor water quality for drinking and other purposes.
While this may be an extreme example, there are many cases where a dramatic reduction in water availability results in significant negative effects on human health. In Lake Chad, a lake shared by Cameroon, Chad, Nigeria and Niger, climate change, the demand for irrigation water upstream, and poor management decisions in the basin have reduced the size of the lake by 90% over the past 40 years. The net effect on the 20 million people, mainly fishers and farmers, who rely directly on the lake is rising levels of malnutrition, in turn leading to a much increased vulnerability to diseases. A major project is underway to reverse this situation.
Many wetland plants and a number of animal species have been used in traditional medicines for millennia and this continues today. They are also used in homeopathic medicines, an ever-growing industry in the developed world, and have a role in the development and production of modern medicines. Over-collection, destructive harvesting techniques, and habitat loss and alteration all challenge the capacity of wetland species to continue to fulfill these roles.
The world's population is becoming concentrated in urban areas, particularly along coasts, and our urban populations are becoming more and more physically inactive. The World Health Organisation estimates that depression and depression-related illness will become the greatest source of ill-health by 2020, and the effects on health of physical inactivity in urban populations is becoming ever more costly in terms of medical treatment. We use urban green spaces, including rivers, lakes and reservoirs, for recreation, for education, and for relaxation. The value of green spaces in improving the mental and physical health of urban populations is gaining greater recognition and current studies indicate measurable physical and psychological benefits from regular contact with urban green spaces. Urban wetlands have a key role to play here.