Unexplained dead frogs & the deadly chytrid virus

Hi Everyone,

Following this harsh winter we've just had, I pulled around 16 dead frogs out of my pond. They were VIVID purple, I thoroughly cleaned out the pond and have since restarted it (as this was a couple of months ago) Does anyone know if it was the cold that did that or was it a virus. I still have a healthy population in in my garden of live, various sized healthy frogs.
Has anyone else had the same? It was just the fact the whole body had not only bloated up (as you'd expect with decomp) but the all over purple color. It was only that one floated to the surface that drew my attention to it.
Just in case people aren't sure I'm mean British wild frogs (Rana temporaria)
Any ideas guys & girls?
Also has anyone ever come up with conclusive proof, the deadly chytrid virus is spread by American Bullfrogs? I only ask because I've read so much conflicting information, a lot blames Xenopus for the spread.
All and any info would be much appreciated.
Thanks.

It was probably the cold. Many frogs hibernate in the mud at the bottom of a pond, and might not survive the winter if it gets too cold, ice gets too thick, too much snow, etc.

Xenopus was probably the original carrier, but have since passed it to bullfrogs, who can carry it asymptomatically as well.

Last winter was particular bad for frogs in garden ponds in the UK, there were reports of mass die-offs all over the country.

The usual cause is lack of oxygen at the bottom of the pond- the best way to prevent this is to make sure that snow is cleared from the pond, so that light can get in and oxygenating plants can keep photosynthesising and producing more oxygen.

Pond Conservation did a survey on winter death in frogs over the last couple of years, a summary of their results is here:

http://www.pondconservation.org.uk/Resources/Pond Conservation/Documents/Big Pond Thaw - Summary.pdf

The worst case they found was 300 dead frogs in one garden pond.

It's possible that the purple colour developed after the frogs had died- purple bacterial growth is not uncommon in low oxygen conditions at the bottom of ponds.

caleb said:

Last winter was particular bad for frogs in garden ponds in the UK, there were reports of mass die-offs all over the country.

The usual cause is lack of oxygen at the bottom of the pond- the best way to prevent this is to make sure that snow is cleared from the pond, so that light can get in and oxygenating plants can keep photosynthesising and producing more oxygen.

Pond Conservation did a survey on winter death in frogs over the last couple of years, a summary of their results is here:

http://www.pondconservation.org.uk/Resources/Pond Conservation/Documents/Big Pond Thaw - Summary.pdf

The worst case they found was 300 dead frogs in one garden pond.

It's possible that the purple colour developed after the frogs had died- purple bacterial growth is not uncommon in low oxygen conditions at the bottom of ponds.

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Thank you both, I was so releaved when I found live heathy frogs still around in the garden.