Arctic polar bears imperilled by man-made pollution

The long term survival of polar bears is being threatened by man-made pollution that is reaching the Arctic.

This conclusion comes from a major review of research into how industrial chemicals such as mercury and organochlorines affect the bears.

The review suggests that such chemicals have a range of subclinical effects.

When added together, these can have a dramatic and potentially fatal impact on the bears' bones, organs and reproductive and immune systems.

The review, an analysis of more than a decade's research into the effect of pollution on bears, is published in the journal Environment International.

A range of man-made pollutants reach the polar Arctic region, carried there in the air and water.

These include toxic metals such as mercury, organohalogen contaminants (OHCs) including organochlorines, and polybrominated diphenyl ethers (PBDEs) and perflourinated compounds (PFCs), which are used industrially in insulating fluids, as coolants, in foams and electronics and as pest control agents.

Such chemicals are often fat-soluble and accumulate in the fat of many animals, which are then eaten by top predators such as polar bears.

These top predators are then exposed to increasingly concentrated levels of toxins.

But the impact of these toxins on polar bears has been difficult to measure, with the only previous studies done by the Arctic Monitoring and Assessment Programme in 1998 and 2004.

That is party because it is logistically difficult to take many and repeated samples of blood or tissue from live polar bears.

Also, only free-ranging healthy animals that are not clinically sick tend to be sampled, making the overall population appear to be healthier than it already is.

ILL EFFECTS Shrinking sexual ability: studies have found correlations between levels of OHCs and smaller and deformed sexual organs in male and female bears Overactive organs: organochlorines increase the activity of liver enzymes, while mercury boosts stress hormones in the blood Mercury damages the bears' nervous systems PCB exposure may lead to decreases in bone mass density

So veterinary scientist and polar bear expert Dr Christian Sonne, of the Department of Arctic Environment at Aarhus University in Denmark, conducted the first review of all pertinent research on the health effects of such contaminants on polar bears.

Previously, Dr Sonne was part of a team of researchers which found that "stress" linked to pollutants and shrinking sea ice appeared to be shrinking polar bears.

His new analysis includes the results of more than 200 organ and skull tissue samples taken from 80 bears in East Greenland between 1999 and 2009, as well as repeated measurements and observations of bears living in the Svalbard archipelago, Norway.

These studies reveal a number of ill-effects associated with industrial pollutants.

However, such studies can only show that contaminant levels are correlated with ill-effects, not that they cause them.

Bears and dogs

So Dr Sonne investigated the direct impacts of Arctic pollutants on two other top predators living in the region, Norwegian Arctic foxes and Greenland sledge dogs.

In 2003, researchers started a two-year study in which they fed Arctic foxes clean or contaminated whale blubber. One fox of a pair of brothers was fed clean food as a control, while the other brother ate contaminated food.

Having eliminated all other influences, such as gender and age, the researchers showed that foxes exposed to environmental levels of pollutants do suffer harmful effects.

For example, PCBs trigger decreases in bone density and damage the liver, mercury and organochlorines cause renal lesions, while OHCs alter the amount of vitamins circulating in the blood.

Similar effects were found in comparable studies on Greenland sledgedogs.

The maximum sea ice extent is declining by about 2.7% per decade

"Polar bear studies are correlative, but that is not conclusive as being 'cause and effect'," explains Dr Sonne.

"So including dogs and foxes as model species is important [because] you use species that are much like polar bears, and the species were exposed to similar food items as polar bears."

The impact on the bears is likely to be greater even than those effects which show up in studies.

"It is really important to understand that all organ systems are tied together," says Dr Sonne.

So individual pollutants may only have subtle, non-clinical effects on particular parts of a bear's body.

But in concert, the overall impact can be devastating, reducing an individual bear's ability to hunt, reproduce and resist disease.

"After being very sceptical, I now feel that the impact on bears may be true," says Dr Sonne.

Climatic impact

He also concludes that climate change will exacerbate the impact of pollutants on the bears.

As the level of sea ice declines with warming temperatures, polar bears are fasting for longer.

That may mean they eat fewer seals and therefore less pollutants overall.

But they will have to burn fat to compensate.

That will release greater concentrations of toxins from their fat stores into their blood, says Dr Sonne.

This will cause further illness, weakening bears that will already be in poorer condition and may be exposed to new and more virulent pathogens capable of surviving in a warmer Arctic.

Dr Sonne's research is published a week after another separate study published in the journal Arctic showed that polar bears in the southern Beaufort Sea in the Arctic Ocean are occurring more frequently on land and open water, and less on the ice.

World's biodiversity 'crisis' needs action, says UN

The UN has launched the International Year of Biodiversity, warning that the ongoing loss of species around the world is affecting human well-being.

Eight years ago, governments pledged to reduce the rate of biodiversity loss by 2010, but the pledge will not be met.

The expansion of human cities, farming and infrastructure is the main reason.

Speaking at the launch in Berlin, German premier Angela Merkel urged the establishment of a new panel to collate scientific findings on the issue.

Achim Steiner, executive director of the UN Environment Programme (UNEP), urged governments and their leaders to renew their commitment to curbing biodiversity loss even though the 2010 goal will be missed.

"The urgency of the situation demands that as a global community we not only reverse the rate of loss, but that we stop the loss altogether and begin restoring the ecological infrastructure that has been damaged and degraded over the previous century or so," he said.

The UN says that as natural systems such as forests and wetlands disappear, humanity loses the services they currently provide for free.

These include purification of air and water, protection from extreme weather events, and the provision of materials for shelter and fire.

With species extinctions running at about 1,000 times the "natural" or "background" rate, some biologists contend that we are in the middle of the Earth's sixth great extinction - the previous five stemming from natural events such as asteroid impacts.

Cash log

The UN Convention on Biological Diversity (CBD) was agreed at the Rio Earth Summit of 1992, alongside the climate change convention.

But it acquired its key global pledge during the Johannesburg summit of 2002, when governments agreed to achieve a "significant reduction" in the rate of biological diversity loss by 2010.

Conservation organisations acknowledge that despite some regional successes, the target is not going to be met; some analyses suggest that nature loss is accelerating rather than decelerating.

"We are facing an extinction crisis," said Jane Smart, director of the biodiversity conservation group with the International Union for the Conservation of Nature (IUCN).

"The loss of this beautiful and complex natural diversity that underpins all life on the planet is a serious threat to humankind now and in the future."

Mrs Merkel backed the idea of forming a scientific panel to collate and assess research on biodiversity loss, as the Intergovernmental Panel on Climate Change (IPCC) assesses evidence on climatic indicators.

"The question of preserving biological diversity is on the same scale as climate protection," she said.

"It would be sensible to have an interface between the politics and the science to integrate knowledge."

Nature loss 'dwarfs bank crisis'

A large on-going UN-sponsored study into the economics of biodiversity suggests that deforestation alone costs the global economy $2-5 trillion each year.

The UN hopes some kind of legally-binding treaty to curb biodiversity loss can be agreed at the CBD summit, held in Japan in October.

One element is due to be a long-awaited protocol under which the genetic resources of financially-poor but biodiversity-rich nations can be exploited in a way that brings benefits to all.

However, given the lack of appetite for legally-binding environmental agreements that key countries displayed at last month's climate summit in Copenhagen, it is unclear just what kind of deal might materialise on biodiversity.

Political football

The UN has been pursuing new ways of raising public awareness on the issue, including a collaboration with the Cameroon football team taking part in the African Nations Cup finals.

Many environment organisations will be running special programmes and mounting events during the year.

"The big opportunity during the International Year of Biodiversity is for governments to do for biodiversity what they failed to do for climate change in Copenhagen," said Simon Stuart, a senior science advisor to Conservation International and chair of IUCN's Species Survival Commission.

"They have the chance to make a major difference; and key to this will be halting species extinctions, the most irreversible aspect of biodiversity loss."

WWF is highlighting 10 species it considers especially threatened, ranging from commercially significant ones such as bluefin tuna to the Pacific walrus and the monarch butterfly.

In the UK, the national IYB partnership - hosted from the Natural History Museum (NHM) - is asking every citizen to "do one thing for biodiversity" in 2010.

The giant Amazon arapaima fish is 'under threat'

The arapaima, a giant species of fish that lurks in the Amazon river, may be threatened by overfishing.

Studies reveal that errors in the classification of the species could mean that it is being pushed closer to the edge of extinction than thought.

The arapaima is the largest freshwater fish with scales in the world.

But there may actually be four species rather than one, say scientists, and a lack of research and management may allow some to be fished to extinction.

The threat to the future of these fish has been revealed in research conducted by Dr Leandro Castello of the Woods Hole Research Center in Falmouth, Massachusetts, US, and Professor Donald Stewart of the State University of New York in Syracuse, US.

They have reviewed what is known about populations of the arapaima, and conducted detailed investigations into the status of the fish in the wild.

Previously, it was thought there was one species of arapaima (Arapaima gigas), which also goes by the common names pirarucu or paiche.

This perspective is based on a taxonomic review done over 160 years ago.

Adults grow to almost 3m in length and can weigh more than 200kg, making the fish the largest with scales living in freshwater anywhere in the world.

They are also air-breathers, coming to the surface every 5 to 15 minutes to gulp air, a behaviour which allows them to colonise muddy oxygen-poor rivers and lakes within the Amazonian basin and prey on other fish that find it difficult to move in such conditions.

However, in an ongoing study, Prof Stewart has analysed nearly all preserved specimens of supposed arapaima available in museums in the world.

So far he has only found one specimen of Arapaima gigas.

The others are suspected to be closely related species, including some as yet unreported.

"Our new analyses indicate that there are at least four species of arapaima," says Dr Castello.

"So, until further field surveys of appropriate areas are completed, we will not know if Arapaima gigas is extinct or still swimming about."

Concern about the fish's numbers comes from other work done by Dr Castello and Prof Stewart.

For a split second, an arapaima surfaces to gulp air

That suggests that arapaima sexually mature relatively late, and need very specific habitats to both live and reproduce.

Their research also shows that populations of the fish are being put under severe pressure by fishermen.

Because of the fish's huge size and habit of coming to the surface, it has long been a favoured fish to catch, with fisherman using harpoons and gill nets to land their prey.

"They have the curse of being tasty and of having to breathe air," says Dr Castello.

Fishermen have been catching large numbers of arapaima in this way since the 1800s.

But now, while a few populations are increasing, others are being overfished, say the researchers, who have published a paper warning of the fish's fate in the Journal of Applied Ichthyology.

And while Brazil implemented regulations to manage arapaima fisheries some 20 years ago, most fishermen do not follow the regulations, say the authors.

Fishermen capture a young arapaima for ecological studies

"Arapaima can be viewed as badly overexploited and under some level of threat of extinction," says Dr Castello.

One solution, they say, is to encourage community-based schemes for fisheries, and there is much need for additional action on the part of the government.

For example, their research shows that fishermen who specialise in hunting arapaima with harpoons can accurately count the fish, due to the fish's habit of breaching the surface for air.

The fishermen can then select a sustainable proportion of the population to hunt.

"Populations of arapaima managed with this system increased about 50% annually, while yielding increasing catches and hence economic profits to the fishermen," says Dr Castello.

Around 100 such community schemes are in place, and some previously overexploited populations have recovered.

"Such results are extremely rare in wildlife conservation, especially in tropical countries where wildlife conservation challenges are greater than elsewhere," says Dr Castello.

But much more needs to be done to research these fish in more detail and prevent overfishing, the scientists warn.

In particular, "the present situation may be one in which one species of arapaima is recovering in certain areas, while unrecognised species are going extinct," they say.