Elephant seals benefit from United States government shutdown


This 29 January 2019 video from California in the USA says about itself:

Government Shutdown Brings Elephant Seals To Point Reyes Beach

Elephant seals used the opportunity of an empty Drake’s Beach on Point Reyes National Seashore – due to the government shutdown – to gather for mating and bearing pups. Wilson Walker reports.

Donald Trump’s shutdown blackmail to try to build his wall was a disaster for many workers; and for national parks and their wildlife. At least, one good consequence, for the elephant seals.

SECOND SHUTDOWN LOOMS AS TALKS BREAK DOWN Talks between congressional Republicans and Democrats aimed at averting another government shutdown have broken down without an agreement. Last month’s federal funding deal runs out on Friday. Acting White House chief of staff Mick Mulvaney said over the weekend another partial government shutdown “absolutely cannot” be ruled out.  [Reuters]

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Climate change, not seals, endanger Baltic Sea fish


This January 2018 video says about itself:

Nord Stream 2 is supporting a program of telemetry studies of the Baltic ringed seal in the Gulf of Finland launched in summer 2017. Telemetry studies using GPS tags deployed on seals allow to collect necessary information on seal behaviour and movement patterns. Expanding scientific knowledge is vital for developing an effective strategy to preserve the population of this protected species. This documentary film explains the methodology and fieldwork conducted by an expert group in 2017.

From Stockholm University in Sweden:

Increasing seal population will not harm largest fish stocks in the Baltic

December 10, 2018

Seals feeding on fish does not decrease fish stocks of Baltic cod, herring and sprat the most — climate change, nutrient load and fisheries do, shows a new study from Stockholm University.

It has long been debated whether the seal predation of fish play a major role in the fish decline in the Baltic Sea compared to human fishing. The debate escalated worldwide since conservation efforts to protect seals and fish-eating birds resulted in increased number of them.

A new study taking into account human pressures on the environment, shows that the seals are not the main problem on commercial fish stocks in the open water of the Baltic Sea.

“We currently have 30,000 grey seals in the Baltic Proper, but we can even have more than 100,000 seals and it will still not affect the amount of cod negatively as much as climate change, nutrient load and fisheries. The Baltic is very sensitive to human impact”, says David Costalago, a former postdoctoral researcher at Department of Ecology, Environment and Plant Sciences, Stockholm University.

The cod population size for example, decreased more by environmental change and by human fishing, than the seals eating the fish. How much fish the seals eat is also affected by the climate and nutrient load.

The scientists made projections by computer simulations that stretch until the year 2098. The scenarios with the highest temperature and nutrient load of the Baltic are damaging to cod but not for herring and sprat. It could lead to a worsened effect of hypoxia and as a result less fish. Higher nutrient load together with higher temperatures could also lead to higher toxic cyanobacterial blooms of low food quality — making fish smaller and slender.

“We need to start to focus on the main problem that the Baltic is facing for its fish populations — which is for example climate change and eutrophication. We need to find ways to both secure the revenues of the fishers and guarantee the conservation of the fish stock and good status of the grey seal population”, says Monika Winder, professor at Department of Ecology, Environment and Plant Sciences, Stockholm University.

The study focused on fish living in the open waters. Therefore, nothing could be said about how seals affect salmon, eel, pike or whitefish that live closer to the coast.

“We want our insights to affect management and conservation that considers the whole ecosystem and multiple pressures, not only the direct biological interaction between fisheries and seal. Often debates about the impact of seals arise from poor understanding of the complexity of predator-prey interactions”, says Monika Winder.

Eleven seal species nearly exterminated


This 2017 video is called Cute baby seals doing funny things compilation.

From Bielefeld University in Germany:

Eleven seal species narrowly escaped extinction

November 16, 2018

Their fur was used as a raw material for coats; their fat was used for oil lamps and cosmetics: right up to the end of the nineteenth century, millions of seals were being hunted and killed every year worldwide. The consequences of this episode of commercial hunting for today’s seal populations is the subject of a study published today (16.11.2018) in Nature Communications. Population geneticists at Bielefeld University and the British Antarctic Survey have found that eleven seal species only narrowly escaped extinction. The scientists managed to include nearly all of the species alive today in their research. The study nevertheless reveals that most species survived the heyday of seal hunting in sufficient numbers to retain most of their genetic diversity.

‘Hunting, epidemics, and climate change all have the potential to reduce the number of individuals in a population to the point where genetic diversity is lost’, says Professor Dr Joseph Hoffman, head of the Molecular Behavioural Ecology research group at Bielefeld University and sub-project manager in the Transregio Collaborative Research Centre NC³ that is studying animals and their individual niches. ‘These extreme population reductions are known as bottlenecks and can affect a species’ potential to survive’.

‘When a species lacks genetic diversity, it has a lower chance of adapting to changing environmental conditions or protecting itself against parasites or pathogens. You can compare the gene pool with a toolbox: the fewer tools you have, the less well-equipped you are for different situations,’ says Hoffman.

The researchers analysed which seal species passed through bottlenecks due to overhunting. They carried out this research in cooperation with colleagues in ten different countries. ‘This enabled us to collect genetic data on thousands of seals from 30 different species’, says Martin Stoffel, the lead author of the study and a doctoral student in Joseph Hoffman’s research group. As there are 33 different seal species alive today, this makes the study the most comprehensive work on the genetic diversity of seals. For example, it even used data from a study of the Antarctic fur seal that lives on Bird Island (South Georgia) in the Sub Antarctic. This research on fur seals is part of the work at the Transregio Collaborative Research Centre NC³.

In their analyses, the researchers used computers to simulate how much genetic diversity would be expected in each seal species if that species were hunted to the brink of extinction around a hundred years ago. They compared these computations with the genetic data from animals living today.

The result: seal hunting around a century ago led to the near extinction of almost one-third of the species studied. ‘Most species have recovered and are still genetically quite diverse despite strong population declines’ says Martin Stoffel.

‘However, there are four exceptions: the northern elephant seal, the Mediterranean monk seal, the Hawaiian monk seal, and the Saimaa ringed seal,’ says Stoffel. ‘The genetic material of individual animals within these species is very similar. These four species only have up to 20 per cent of the genetic diversity of those species that have been hardly or not hunted at all. In the northern elephant seal, for example, only few dozen individuals survived hunting to rebuild the current population of over 200,000 animals.’ Stoffel is an expert on the northern elephant seal. To study them for his dissertation, he went on an expedition to the Islas San Benito, an uninhabited group of islands off the Mexican Pacific coast.

Which factors explain why certain species suffered more from being hunted than others? The study confirms that ‘species that bear their young on land declined much more strongly as a result of excessive hunting than species that give birth on ice,’ says Stoffel. ‘This is probably because those giving birth on ice tend to live in remote Arctic and Antarctic areas where they were out of reach of hunters.’ Population bottlenecks can also be found in those species where a single male defends a harem of several dozen females during the breeding season. ‘This is the case with the northern elephant seal and the southern elephant seal just as much as the Antarctic fur seal’, says Stoffel. ‘Their mating systems result in dense aggregations of breeding animals, making them easier for hunters to kill.’

Whereas at the end of the nineteenth century, millions of seals were still being killed by hunters, the German animal protection society (Tierschutzbund) reports that nowadays, 750,000 seals are killed each year for commercial purposes. Most of these seals are now being hunted in Canada, Greenland, and Namibia.

Scientists have already observed and predicted that high ringed seal pup mortality rates are linked to poor environmental conditions like early ice breakup and low snow. Researchers have now gone a step further by coupling these hypotheses with forecasts of future spring snow and ice conditions, developing a mathematical model, and following it to some stark conclusions for populations off the Amundsen Gulf and Prince Albert Sound in Canada: here.