European Union failing threatened mediterranean sharks

Oceana, the international marine conservation organisation, denounces the European Commission for blocking efforts to protect threatened and endangered sharks and rays in the Mediterranean Sea, under the Barcelona Convention. The protection of ten species of sharks and rays is one of the key issues for discussion at the biennial meeting of the Convention, which begins today in Paris. Non-EU nations within the Convention have already expressed their support for protecting these species.

The potential inclusion of these fish on a list of strictly protected species hinges on the EU’s vote. Yet, despite having had months to do so, the European Commission has not yet adopted a common position on the issue with European Member States. Meanwhile, in 2009, EU Member States together accounted for the highest level of reported shark catches globally (16%), which were caught in European, high seas, and third-country waters.

“After delaying this decision twice already, because they wanted more time for ‘internal discussions’, it is inexcusable that the European Commission could not manage to resolve its bureaucratic issues in time for this critical meeting,” said Ricardo Aguilar, Research Director for Oceana in Europe. “The Commission says “we need to protect sharks” but when it comes to the Mediterranean, their actions indicate the opposite, even going so far as to warn against protecting threatened species at a recent meeting on Mediterranean sharks[i].”

The Mediterranean is the region of greatest risk globally to sharks and rays, with 41% of species considered threatened, compared to 17% globally. Of the ten species under consideration at this week’s meeting, some have undergone severe population declines, including porbeagles, shortfin makos, and hammerheads, whose Mediterranean populations have been reduced by up to 99.9% during the 20^th Century. Others, such as the sandy skate, Maltese skate, and common guitarfish, have vanished from some areas where they were once common. All of the species are threatened by overfishing, despite already being included on a list of species whose capture must be regulated for conservation reasons.

“It is incomprehensible that the European Commission has taken so long to resolve its position on such a clear-cut issue: highly threatened sharks and rays are being fished, and urgently require greater protection,” added Dr. Allison Perry, marine wildlife scientist with Oceana in Europe. “The EU has a responsibility – under both European law and as a signatory to the Barcelona Convention – to take precautionary measures to ensure their conservation. There is still a window of opportunity in Paris, and we trust that EU Member States and the Commission will coordinate a swift decision to grant these species the protection they deserve.”

The 17th Meeting of the Contracting Parties to the Barcelona Convention gathers policymakers from 21 Mediterranean nations and the European Union, to discuss the environmental health of the Mediterranean Sea and to decide matters related to its protection. In addition to shark and ray conservation, important issues to be discussed this week include the protection of marine areas in the open sea, and pollution resulting from offshore drilling.

Fact sheet: Barcelona Convention. The necessity of Annex II protection for threatened sharks & rays

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[i] General Fisheries Commission for the Mediterranean, 12-16 December 2011: “The DG-MARE representative warned that RAC/SPA should not take IUCN advice automatically because too many species of great commercial value would be included in Appendix II.” (page 12; full report here)

http://oceana.org/en/eu/media-reports/press-releases/european-union-failing-threatened-mediterranean-sharks

Seagrass ‘tens of thousands of years old’

Meadows of seagrass found in the Mediterranean Sea are likely to be thousands of years old, a study shows.

Researchers found genetically identical samples of Posidonia oceanica up to 15km apart, which suggested that the species was extremely long-lived.

The team added that the organism - which provides food and shelter for many species - is under threat from climate change.

They report their findings in the open access journal Plos One.

The seagrass is "partially clonal", explained co-author Sophie Arnaud-Haond from the French Research Institute for the exploration of the Sea (Ifremer).

"This means they can reproduce sexually through flowering and recombination of male and female genomes, or clonally through the exact replication of the genome of an individual forming a new plant module through clonal growth," she told BBC Nature.

Asexual reproduction, such as cloning, means an individual organism's genetic identity is preserved and passed on from generation to generation, whereas the offspring of sexual organisms is made up of genetic material from both parents.

Read more:  http://www.bbc.co.uk/nature/16811538

Mediterranean sharks are Australian immigrants

Antipodean great whites took a wrong turn on the way to South Africa.

Joseph Milton

The elusive great white sharks of the Mediterranean Sea may be descended from a single small Australian population that lost its bearings while visiting South Africa 450,000 years ago.


The great whites (Carcharodon carcharias) were probably returning to the Antipodes but became trapped after passing through the Straits of Gibraltar, according to a team led by marine biologist Leslie Noble of the University of Aberdeen, UK. The sharks have since made the Mediterranean their home because they reproduced there and, like salmon, the young always return to their birthplace.

Little is known about Mediterranean great whites — sightings are rare and tissue samples even rarer — but Noble and his colleagues teamed up with Turkish researchers to get access to samples from four sharks caught in fishing nets: two from Turkey, one from Tunisia and another from Sicily.

Their research, published today in Proceedings of the Royal Society B1, suggests that a combination of climate change, high sea levels and strong ocean currents around the South African coast could have driven the migrating Australian sharks off-course, up the west coast of Africa and east into the Mediterranean. But because the initial population was small, genetic variability in modern Mediterranean sharks seems to be limited — indicating that a lack of diversity could threaten their future survival. Female sharks from the nearby Atlantic do not seem to be migrating to the region, where they could help to replenish the stagnant gene pool.

Lost at sea
The researchers sequenced an area of the four sharks' mitochondrial DNA — DNA that is passed onto offspring from the mother and encodes proteins from cells' energy factories. The team was then able to compare the genetic code with a bank of sequences derived from great whites in waters of different parts of the world, including South Africa, Australia and the Atlantic.

Noble says the team was surprised to find that the section of DNA sequenced was identical in three of the four Mediterranean sharks, and showed that they were most closely related to Australian great whites. The team had expected to see more affinity with the nearer Atlantic or western Indian Ocean populations.

Great white sharks were once thought of as a coastal species, but research has shown that they migrate long distances in the open ocean — although scientists do not know exactly why. Tagged sharks have been seen travelling between the coasts of South Africa and southern Australia, and the authors suggest that it was probably during one of these excursions that a group took a wrong turn.

The researchers used a molecular dating technique based on the number of differences between the DNA of the Mediterranean and Australian sharks to estimate that the sharks got lost during the Pleistocene epoch, around 450,000 years ago. Noble says that this was an period between ice ages: a time of high sea levels, climate change and, perhaps most importantly, an unusually fast-flowing ocean eddy off the east coast of South Africa called an Agulhas ring — which may explain why the sharks went so far astray.


The warm Agulhas Current flows down the east coast of Africa, but periodically an Agulhas ring carries its waters around the southern tip of the continent and into the Benguela Current off the west coast. "When sharks follow the Agulhas Current, the cooler waters of the Benguela probably alert them to turn east," says Nelson, "but an Agulhas ring is like a warm-water bubble." A group of sharks swimming in one of these bubbles could miss the turning and find the western coast of Africa between it and its desired destination.

The researchers speculate that the sharks then swam north until the Mediterranean basin gave them a chance to head east again. Once in the basin, they may have become trapped by the peninsulas and narrow channels of the Medterranean.

A population in peril
Paulo Prodöhl, an evolutionary geneticist at Queen's University Belfast, UK, says that although the finding "comprises a precious and unique data set, the sample sizes are really too small to draw conclusive inferences". But he admits that because shark samples are so hard to get hold of, "you have to work with what you can get".

"We recognize the sample-size problem," says Noble. "We're trying to get another 50 Mediterranean samples, which could dramatically change our inferences — we're very keen to access museum material."

But, he says, "I don't think it removes the central tenet — that as far as we're aware, a significant proportion of the Mediterranean sharks are Australian in origin."


Noble also hopes that the work will highlight the plight of a potentially fragile shark population surviving in a polluted and over-fished sea. He says that great whites occupy a "pivotal role" in the Mediterranean, and the removal of top predators from other marine ecosystems has been disastrous.

"On the east coast of America, shark eradication has caused an 'ecological cascade'," says Noble. Populations of species on which sharks prey, such as seals and dolphins, have exploded, unbalancing the whole system. "It's been instrumental in helping kill off some of the shellfish," says Noble. "I wouldn't like to speculate on the consequences for the Mediterranean if this population became extinct."

http://www.nature.com/news/2010/101117/full/news.2010.616.html

Mediterranean sharks are Australian immigrants

Antipodean great whites took a wrong turn on the way to South Africa.

Joseph Milton

The elusive great white sharks of the Mediterranean Sea may be descended from a single small Australian population that lost its bearings while visiting South Africa 450,000 years ago.


The great whites (Carcharodon carcharias) were probably returning to the Antipodes but became trapped after passing through the Straits of Gibraltar, according to a team led by marine biologist Leslie Noble of the University of Aberdeen, UK. The sharks have since made the Mediterranean their home because they reproduced there and, like salmon, the young always return to their birthplace.

Little is known about Mediterranean great whites — sightings are rare and tissue samples even rarer — but Noble and his colleagues teamed up with Turkish researchers to get access to samples from four sharks caught in fishing nets: two from Turkey, one from Tunisia and another from Sicily.

Their research, published today in Proceedings of the Royal Society B1, suggests that a combination of climate change, high sea levels and strong ocean currents around the South African coast could have driven the migrating Australian sharks off-course, up the west coast of Africa and east into the Mediterranean. But because the initial population was small, genetic variability in modern Mediterranean sharks seems to be limited — indicating that a lack of diversity could threaten their future survival. Female sharks from the nearby Atlantic do not seem to be migrating to the region, where they could help to replenish the stagnant gene pool.

Lost at sea
The researchers sequenced an area of the four sharks' mitochondrial DNA — DNA that is passed onto offspring from the mother and encodes proteins from cells' energy factories. The team was then able to compare the genetic code with a bank of sequences derived from great whites in waters of different parts of the world, including South Africa, Australia and the Atlantic.

Noble says the team was surprised to find that the section of DNA sequenced was identical in three of the four Mediterranean sharks, and showed that they were most closely related to Australian great whites. The team had expected to see more affinity with the nearer Atlantic or western Indian Ocean populations.

Great white sharks were once thought of as a coastal species, but research has shown that they migrate long distances in the open ocean — although scientists do not know exactly why. Tagged sharks have been seen travelling between the coasts of South Africa and southern Australia, and the authors suggest that it was probably during one of these excursions that a group took a wrong turn.

The researchers used a molecular dating technique based on the number of differences between the DNA of the Mediterranean and Australian sharks to estimate that the sharks got lost during the Pleistocene epoch, around 450,000 years ago. Noble says that this was an period between ice ages: a time of high sea levels, climate change and, perhaps most importantly, an unusually fast-flowing ocean eddy off the east coast of South Africa called an Agulhas ring — which may explain why the sharks went so far astray.


The warm Agulhas Current flows down the east coast of Africa, but periodically an Agulhas ring carries its waters around the southern tip of the continent and into the Benguela Current off the west coast. "When sharks follow the Agulhas Current, the cooler waters of the Benguela probably alert them to turn east," says Nelson, "but an Agulhas ring is like a warm-water bubble." A group of sharks swimming in one of these bubbles could miss the turning and find the western coast of Africa between it and its desired destination.

The researchers speculate that the sharks then swam north until the Mediterranean basin gave them a chance to head east again. Once in the basin, they may have become trapped by the peninsulas and narrow channels of the Medterranean.

A population in peril
Paulo Prodöhl, an evolutionary geneticist at Queen's University Belfast, UK, says that although the finding "comprises a precious and unique data set, the sample sizes are really too small to draw conclusive inferences". But he admits that because shark samples are so hard to get hold of, "you have to work with what you can get".

"We recognize the sample-size problem," says Noble. "We're trying to get another 50 Mediterranean samples, which could dramatically change our inferences — we're very keen to access museum material."

But, he says, "I don't think it removes the central tenet — that as far as we're aware, a significant proportion of the Mediterranean sharks are Australian in origin."


Noble also hopes that the work will highlight the plight of a potentially fragile shark population surviving in a polluted and over-fished sea. He says that great whites occupy a "pivotal role" in the Mediterranean, and the removal of top predators from other marine ecosystems has been disastrous.

"On the east coast of America, shark eradication has caused an 'ecological cascade'," says Noble. Populations of species on which sharks prey, such as seals and dolphins, have exploded, unbalancing the whole system. "It's been instrumental in helping kill off some of the shellfish," says Noble. "I wouldn't like to speculate on the consequences for the Mediterranean if this population became extinct."

http://www.nature.com/news/2010/101117/full/news.2010.616.html