Why scientists are counting seal pups in the Thames Estuary

By Helen BriggsBBC News

29 June 2018

Sixty years ago the Thames Estuary was regarded as "biologically dead" and largely devoid of wildlife.

But, in recent years seals have returned to the Thames as well as to the coastal and low-lying lands bordering the estuary.

Last year, scientists recorded more than 3,500 harbour and grey seals.

Now, they are starting the first count of seal pups to see how important the area is a breeding ground.

"These seals are higher predators in the estuary," says Thea Cox, conservation biologist at the Zoological Society of London.

"Knowing how many there are is a really good indicator of the health of the estuary, what habitat is available to them, what food source is available to them."

Continued  

Avian influenza virus isolated in harbor seals poses a threat to humans

Date:

September 4, 2014

Source:

St. Jude Children's Research Hospital

Summary:

The avian influenza A H3N8 virus that killed harbor seals along the New England coast can spread through respiratory droplets and poses a threat to humans, scientists have found. The findings reinforce the need for continued surveillance of flu viruses circulating in wild and domestic animals to understand the risk the viruses pose to humans, said the study's first author.

Continued ...

Seal population on the rise in Thames estuary

Numbers returning to natural level after centuries of culling for meat and fur, survey finds

Damian Carrington

theguardian.com, Thursday 4 September 2014 05.30 BST

Seals are prospering in the greater Thames estuary as populations bounce back from centuries of culling, according to a new scientific survey.

The research suggests hundreds of new seals visited the estuary in 2014, with some taking in the sights of central London by swimming all the way up to Teddington lock, the end of the tidal river.

The survey by Zoological Society of London researchers took advantage of the seals’ moulting season in August, when they bask on sunny sand banks whilst growing a new winter coat. Compared to the first survey in 2013, the team found the population of harbour seals had increased slightly to 679 while grey seal sightings more than doubled to 449.

Seals were killed for meat and fur until the practice was outlawed in 1970 and, despite their proximity to the capital, the Thames seals are the least understood population in the UK.

Continued ...

Seal deaths caused by propellers break environmental law, ministers warned

Wildlife groups write to UK and Scottish parliaments seeking a ban on covered propellers blamed for horrific 'corkscrew' injuries

Rob Edwards

theguardian.com, Wednesday 26 February 2014 07.00 GMT

Ministers are breaking environmental law by failing to prevent harbour seals from being sliced to death by ships' propellers, according to a coalition of 13 wildlife groups.

The groups have written to the UK and Scottish governments demanding immediate area bans on the covered propellers blamed for inflicting horrific "corkscrew" injuries on hundreds of seals and porpoises.

Declining populations of harbour seals on the east coast of Scotland could be wiped out, they warn. This would expose ministers to multimillion pound fines for breaching the European habitats directive, that gives the seals legal protection.

Continued

New flu virus found in seals concerns scientists

Scientists in the United States have identified a new strain of influenza in harbour seals that could potentially impact human and animal health.

The H3N8 flu has been associated with the deaths of harbour seals in New England last year.

Researchers say the virus may have evolved from a type that had been circulating in birds.

They say the discovery highlights the potential for pandemic flu to emerge from unexpected sources.

Researchers were puzzled by the mysterious deaths from pneumonia of 162 harbour seals around the coast of New England last year.

Autopsies on five of the marine mammals indicate that they died from a type of H3N8 influenza A virus that is closely related to a strain circulating in North American birds since 2002.

One of authors of the research paper is Prof Ian Lipkin, from Columbia University in the US. He is a celebrated virus hunter who in the past has helped identify West Nile virus and Severe Acute Respiratory Syndrome (SARS). He told the BBC that finding this flu virus in seals was an interesting "new jump".

"It's something that's been circulating for a while in birds, but we've not had this sort of die off relating to this virus in the past. As we've looked at it in some detail, we've found there have been mutations in this virus which enable it to bind to both bird receptors for flu as well as mammalian receptors for flu."

Continued:  http://www.bbc.co.uk/news/science-environment-19055961

Two Ontario seals die during transport to U.S. zoo

Two harbour seals from a London, Ont. theme park died as they were being transported to the Saint Louis Zoo, where they were expected to live their final years in a new, state-of-the-art exhibit, city officials announced Sunday.

The seals, named Nunavut and Atlantis, died as they were being driven in an air-conditioned trailer equipped specifically for marine mammal transport.

They were on their way from Storybook Gardens in London, which is in the process of transferring all of its zoo animals -- including a beaver, otter, lynx and birds of prey -- to sanctuaries in Canada and the United States.

A third seal, named Cri Cri, had to be taken to the Indianapolis Zoo, where she remains for treatment, after falling ill during the trip.

A fourth seal, named Peanut, arrived safely at the St. Louis facility on Saturday and will remain in quarantine for the required 30-day period.

"This is a deeply sad day for Londoners and all those people who knew and loved our Storybook seals," London Mayor Joe Fontana said in a statement issued on Sunday. "No one could have foreseen this terrible tragedy."

Fontana went on to say that veterinarians from both London and St. Louis inspected the animals earlier this year and found "no significant health issues."

Fontana said the cause of the animals' distress is not yet known.

"It is a sad day especially for Storybook staff who have loved and cared for these seals for years," Fontana said. "We were trying to do what was best for the seals: find them a more appropriate place to live out their years."

Storybook Gardens is a family oriented theme park that offers rides, games, a water park and other entertainment geared to children. A trail that runs through the park is called "Storybook Valley," and features landmarks from popular children's stories.

According to a timeline of events provided in Fontana's statement, a curator with the Saint Louis Zoo who was travelling with the seals observed that the animals seemed fine around the time they passed through U.S. Customs around 1 p.m. on Friday. At that time, they were also inspected by the U.S. Department of Fish and Wildlife Service.

The animals also seemed fine during another check two hours later.

But during another check one hour and 45 minutes after that, one of the seals was not responsive. The curator contacted the nearest zoo, the Fort Wayne Children's Zoo, where officials confirmed one seal had died and another was showing signs of distress. After attempts were made to save its life, the second seal also died.

At the same time, the third seal, Cri Cri, began showing distress symptoms, and was treated, stabilized and monitored through the night. However, she had to be left at the Indianapolis Zoo when she began exhibiting behavioural changes as the transport continued toward St. Louis.

Peanut, the fourth seal, arrived in St. Louis appearing "healthy and alert," Fontana's statement said.

Dr. Jeffrey Bonner, president and CEO of the Saint Louis Zoo, offered his condolences to the Storybook Gardens staff.

"When Storybook Gardens asked us to provide a home for four harbour seals, we were happy to step forward and provide an opportunity for these animals to live out their golden years in our new, state-of-the-art exhibit," Bonner said. "We do everything we can when transporting animals to ensure their safety and comfort, but there is always some risk inherent in any animal transport."

A veterinary pathologist will perform a necropsy on both animals. The animals' cause of death will not be known until all testing is complete, which may take several weeks.

Florine Morrison, a director of Zoocheck Canada, an agency that helped co-ordinate and pay for the seals' transfer, said "we only learned about the seals deaths Sunday morning. We were shocked by the news and we look forward to answers from the Saint Louis Zoo as to the cause of death and to understand if protocols were carefully followed during the transport."

Read more: http://www.ctv.ca/CTVNews/Canada/20120610/london-ontario-seals-120610/#ixzz1xVMuVi00

U.S. government joins probe of mysterious seal deaths

(Reuters) - Federal officials have joined an investigation into the mysterious deaths of young harbor seals, as the number of dead seals discovered on beaches across three states in New England rose to 49.

Seals began washing up on the beaches of northern Massachusetts, New Hampshire and southern Maine last week, said Maggie Mooney-Seus, a spokeswoman for the National Oceanic and Atmospheric Administration's office in Gloucester, Massachusetts.

"Some of them have been decomposed," she told Reuters on Wednesday. "We're hoping we're not going to see a lot more. We don't know at this point what's caused it."

The densest cluster of seal deaths has been along New Hampshire's 18-mile coast, where 17 seal carcasses have been recovered since Friday, said Tony Lacasse, a spokesman for the New England Aquarium in Boston.

The aquarium has conducted autopsies on three of the least-decomposed seals and found that they all had an adequate layer of blubber to survive.

That suggests the young seals did not die because of a failure to develop hunting skills, which causes the natural deaths of about 30 percent of harbor seals after they are weaned from their mother, Lecasse said.

"The results were a little surprising to us," Lecasse said. "We're doing tissue sampling and have sent those out to labs across the country."

Results are expected next week, and could indicate whether seals died because of disease, toxins or another cause, he said.

Massachusetts, New Hampshire and Maine are home to large populations of harbor seals, which occasionally draw great white sharks and other predators to their breeding grounds.

By Jason McLure
http://uk.reuters.com/article/2011/10/05/us-seals-idUKTRE7944N020111005

Female seals drawn to deadly ship propellers because they sound like male mating call

Female seals who suffered mysterious "corkscrew" injuries were drawn into ship propellers because the blades produce the same acoustics as a male seal's mating call, scientists believe.

Experts at the Sea Mammal Research Unit at St Andrews University had previously suspected that ships were responsible for killing the seals in such a horrific way - but did not know why this was happening.

Of seven harbour seals found along the Fife coast with the horrific trademark injuries this summer, five turned out to be females.

But the scientists from the unit have now traced twice as many seals killed by the corkscrew injuries - first reported last year - and over a wider area and period.

They have found that virtually all the deaths in the summer are adult females and in the winter juveniles.

At first the phenomenon baffled scientists until they struck on the theory that the sound of certain ship's propellers may be attracting the female seals.

They have now carried out acoustic tests on both captive and wild seals - playing recordings of propellers - which seems to back-up the theory.

The experts admit that while it explains the death of the females, it is still a mystery so far why the juveniles are being attracted.

The SMRU's preliminary report will be presented to Marine Scotland by the end of the year.
The scientists are now convinced that the corkscrew wounds are caused by ducted propellers from coastal inshore boats - and not sharks.

The corpses of at least 50 seals bamboozled experts at first because they had all suffered a single smooth-edged cut spiralling the length of their body.

Since last year the total of "corkscrew" deaths has now risen to 90.

Dr David Thompson, the researcher leading the investigation, said: "Investigations have revealed a number of features that show the injuries are entirely consistent with the animals being sucked through large ducted propellers.

"The number and range of deaths is more extensive than we first thought. They are more extensive in the UK - we now have confirmed cases in the Firth of Forth, Aberdeenshire, Ardrossan in Ayrshire, Orkney, Northumberland, Strangford Lough in Ireland, as well as the previous ones in Fife and Norfolk.

"Seals with similar characteristic spiral or corkscrew injuries have been reported from Atlantic Canada for at least the last 15 years at Sable Island off Nova Scotia and the Gulf of St Lawrence.

"What we have found is that in the summer the deaths are almost exclusively adult female harbour seals and in the winter mostly juvenile grey seals.

"The possibility is that the females are being attracted by the sound of the motors. Seals communicate at a similar low frequency roar during the breeding season.

"It is clear that the seals are responding inappropriately to some aspect of the operation of these devices. The localisation in space and time of these events makes it unlikely that the seals are being hit as a result of random coming together of swimming animals and fast moving vessels. The concentration of carcasses in each locality suggests that the vessels must be either stationary or slow moving but operating their propellers, such as when using motors for dynamic positioning. This suggests that some aspect of the operation of these devices is attracting the seals to within a danger zone from which they do not appear to be able to escape. Developing any mitigation measure will require that we identify and understand the attractive mechanism.

"An acoustic cue is suggested by the fact that all seals killed during summer month have been female harbour seals which are thought to be attracted by underwater calls of breeding males. Juvenile grey seals which are the main victims during winter months in Norfolk and Scotland have also been shown to be attracted by conspecific calls with a pulsing rhythmic pattern."

Trials have been taking place looking at matching the sounds of boats and the mating calls of seals.
"We have not identified the propeller types yet, but if we do we have the potential to change the sound and possibly avoid these types of deaths," said Dr Thompson.

"But we believe that workboats are highly likely to be involved - and in recent years there are more and more of these type of boats working in coastal waters. That is why the problem appears to be increasing.

"We think these corkscrew deaths have now been around in the UK since the 1980s. We do not know the extent of the problem. We know that only a tiny proportion of the 30,000 plus seals that die each year in UK waters are washed ashore.

"Our methods included scaled simulations using models that show how the spiral injuries can be created, as well as fine-scale observation of the injuries themselves that show the lacerations were made by the seals rotating against a smooth edged blade while at the same time being dragged past the blade by a powerful force.

"Most diagnostic of all has been the imprint on some animals of the serrated 'rope cutter' that is present on most of these types of ducted propellers to stop ropes getting entangled in the propellers."

http://www.telegraph.co.uk/earth/wildlife/8722274/Female-seals-drawn-to-deadly-ship-propellers-because-they-sound-like-male-mating-call.html