2500 seals found dead along Caspian Sea

[Kyng]

https://www.bbc.co.uk/news/world-europe-63852395

About 2,500 seals have been found dead on the Caspian Sea coast in southern Russia, officials say.

Officials say there is no sign that they died violent deaths.

Some 700 dead seals were initially reported, but further investigation has revealed a much higher number and counting continues.

Caspian seals have been classified as endangered on the International Union for Conservation of Nature (IUCN) red list since 2008.

Zaur Gapizov, head of the Caspian Environmental Protection Center, said in a statement that the seals probably died about two weeks ago.

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Rather sad to hear... especially considering this is an endangered species .

We don't yet know what caused their deaths (nor whether the cause was natural or man-made, or some combination of the two) - but at the very least, it looks like it wasn't violence. Whatever it was, I hope they're able to identify it, so we can try and stop this happening again.

[Ann]

I agree, Kyng, seeing that they are considered on the verge of extinction.  What a huge loss!  At least they believe that they didn’t die violently.

[Pyrite]

How sad. I wonder if something about the sea itself has changed due to human activity. Mass mortality events are more common in ungulates - a few people might remember about thousands of saiga antelopes dying simultaneously due to a disease brought on by a warmer climate. Perhaps something similar occurred here?

At any rate, I hope that Russia allows scientists a chance to look at the bodies to determine a cause of death.

[Kyng]

How sad. I wonder if something about the sea itself has changed due to human activity. Mass mortality events are more common in ungulates - a few people might remember about thousands of saiga antelopes dying simultaneously due to a disease brought on by a warmer climate. Perhaps something similar occurred here?

At any rate, I hope that Russia allows scientists a chance to look at the bodies to determine a cause of death.

Indeed, I thought of that too . From what I recall, those die-offs have been happening since at least the 1980s - but the warming climate has made it worse in recent years.

Could be a similar story here.

[Pyrite]

So I decided to do a little bit of digging into the subject. This paper, published in Science, linked a mass mortality event of approximately 400 harbour seals in 1979 to a strain of influenza. A later paper, published in Nature, found another event - this time of 20,000 Mediterranean monk Seals in 1988, to be due to morbillivirus.

There are some other articles, such as this one, which discuss the possibility of avian influenza infecting seals and other mammals. Now, we know that there has been a large outbreak of avian flu in the UK and across Europe this year, so my working theory is that it could have been passed on from birds to seals and caused the deaths. It's just a theory though, and it may yet come out that the deaths came from a completely different origin. It's fun to speculate, though.

EDIT: So I went to YouTube next...apparently there was a recent mass die-off of cape fur seals in Namibia - most of these were prematurely born seal pups. These deaths seem to have been linked to starvation, with changes to water temperature and oxygen level also mentioned. Just a few more possibilities.

[Kyng]

Sounds like some good research you've been doing !

Of course, these all happened at different times, to different species, in different parts of the world - and they all had different causes. So, it's hard to draw any firm conclusions from any of these past events, but they do suggest possibilities that can be put to the test!

[Pyrite]

Oh absolutely, until any studies can be done on the seals themselves, it's all pure speculation. But it's interesting to look into as I hadn't previously come across any mass die-offs in other species besides the saiga antelope.