Saving the sturgeon

The most expensive fish on Earth

Sturgeon is the common name used for some 25 species of fish in the family Acipenseridae, including the genera Acipenser, Huso, Scaphirhynchus, and Pseudoscaphirhynchus. The term includes over 20 species commonly referred to as sturgeon and several closely related species that have distinct common names, notably sterlet, kaluga, and beluga. Collectively, the family is also known as the true sturgeons. Sturgeon is sometimes used more exclusively to refer to the species in the two best-known genera, Acipenser, and Huso. Sturgeons have been referred to as "primitive fishes" because their morphological characters have remained relatively unchanged since the earliest fossil record.

Sturgeons are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America. They are distinctive for their elongated bodies, lack of scales, and occasional great size: sturgeons ranging from 7–12 feet (2-3½ m) in length are common, and some species grow up to 18 feet (5.5 m). Most sturgeons areanadromous bottom-feeders, spawning upstream and feeding in river deltas and estuaries. While some are entirely freshwater, a very few venture into the open ocean beyond near coastal areas.

Several species of sturgeons are harvested for their roe, which is made into caviar — a luxury food which makes some sturgeons pound for pound the most valuable of all harvested fish. Because they are slow-growing and mature very late in life, they are particularly vulnerable to exploitation and to other threats, including pollution and habitat fragmentation. Most species of sturgeons are currently considered to be at risk of extinction, making them more critically endangered than any other group of species.

in Wikipedia

Ancient sturgeon in China's Yangtze 'nearly extinct'

The Chinese sturgeon, thought to have existed for more than 140 million years, is now on the brink of extinction, according to local media.

Chinese scientists released artificially-bred sturgeons into the Yangtze river in April

Xinhua reported that no wild sturgeon reproduced naturally last year in the Yangtze river.

It was the first time since researchers began recording levels 32 years ago.

Chinese researches say the fall is due to rising levels of pollution in the Yangtze river and the construction of dozens of dams.

Researchers from the Chinese Academy of Fishery Sciences also found that no young sturgeons were found swimming along the Yangtze toward the sea during the period they usually do so.

A researcher told Xinhua that in the 1980s, at least several thousand sturgeon could be found in the river. It is estimated only around 100 fish remain.

"Without natural reproduction, the fish population cannot replenish itself. If there are no further steps taken to strengthen conservation, the wild sturgeon faces the danger of extinction," he said.

Several sturgeon fish are housed in the Beijing aquarium

The finless porpoise, another native species to the Yangtze river, is said to be at risk as well

In recent decades the Chinese authorities have built numerous dams along the 6,300km-long Yangtze river to boost the country's electricity supply. Such moves have drawn criticism of environmental degradation and displacement of villagers.

The WWF says that one of two species of dolphins native to the Yangtze river, the Baiji dolphin, went extinct in 2006 because of declining fish stocks.

The other species, the finless porpoise, is said to be at risk from illegal and intensive fishing practices and pollution. About 1,200 to 1,800 finless porpoises remain in the entire 1.8 million sq km Yangtze basin.

From BBC news Sci/environment

Vultures: Nature’s rubbish collectors who never strike

Vultures are often derided for being ugly and smelly, but these incredibly efficient scavengers help humanity by eating dead animals. And India has recently found just how crucial this role is to our well-being.

They are nature’s most opportunistic scavengers, soaring effortlessly in the air on the lookout for their next meal. Mankind has often treated these birds with disgust, but recently it’s been revealed how much we owe them.

Vultures feed on the carcasses of dead animals, helping lessen the chance of disease outbreaks – a fact that was starkly revealed in India over the last few decades. Widespread use of a drug to treat livestock ended up poisoning the birds. “We think we’ve lost somewhere around 40 million birds in the space of two decades, it’s probably the biggest population crash that has ever happened,” says Jemima Parry-Jones, director of the International Centre for Birds of Prey.

In this film, Parry Jones, Dr Ananya Mukherjee of the Saving Asian Vultures from Extinction (Save), Dr M Sanjayan of The Nature Conservancy and environmental economist Pavan Sukhdev reveal what happened next. Without the vultures, carcasses rotted, creating a breeding ground for diseases and leaving a terrible stench. Feral dogs thrived, bringing with them a rise in rabies; India now has the highest number of rabies cases in the world.

Now livestock are being treated with a drug that doesn’t harm vultures, in the hope that the population will recover so that they can return to their vitally important role. As Parry-Jones says: “People tend to think they’re ugly, dirty and smelly, and they’re far from it and they’re absolutely crucial to the environment. They’re the only dustmen in the world who’ve never gone on strike.”

From BBC- Future

Shark cull in Western Australia blocked by regulator

Western Australia's shark cull is to be halted after the state's environmental regulator advised against it.

No great white sharks were among the 172 sharks caught during the trial cull earlier this year

Earlier this year, baited traps known as drum lines were set up as a trial along seven beaches to catch sharks, after a series of fatal attacks.

But the policy was controversial, with critics arguing it could damage the marine ecosystem.

The regulator cited "a high degree of scientific uncertainty" about the impact on the white shark population.

The Environmental Protection Agency (EPA) said it had weighed the potential impact of the plan against the need to maintain "the diversity, geographic distribution and viability" of marine life.

It made particular reference to the white shark, because it is listed as a "vulnerable" species.

Experts consulted by the EPA said there was "too much uncertainty in the available information and evidence about the south-western white shark population, population trends and the bycatch from commercial fisheries".

"In view of these uncertainties, the EPA has adopted a cautious approach by recommending against the proposal," EPA Chairman Dr Paul Vogel said.

The state government had sought to continue the programme each summer for three more years.

During the initial 13-week trial, from July to April 2014, more than 170 sharks were caught.

None were great white sharks, however, to whom most of the recent fatal attacks had been attributed.

State Premier Colin Barnett said he was disappointed at the decision but said an appeal was unlikely.

He said he believed beaches in Perth were safe but voiced concern about beaches in Western Australia's south-west.

Speaking to the Australian Broadcasting Corporation on Friday, he suggested fisheries officers could be given powers to issue kill orders for large sharks lingering in popular swimming areas.

"I think if you have, I'd use the term rogue shark, a shark that stays in one area for repeated periods, I think we need to catch that shark and remove it," he said.

From BBC News- Sci/Environment