dying tadpoles

amanda berry · #1 (**permalink**) 26-07-2009, 07:37 AM

I started this year with lots of frogspawn - and then a pond full of tadpoles. But they have disappeared. There are one or two lurking around - but looking closer, I wonder if they could be diseased or ill. I had a pretty good look at one and it was just not quite right. And was obviously dying - or maybe even dead.
They all disappeared last year as well - but I put this down to a 'bad year'. But was really disappointed not to have little frogs to watch.
The pond is well established - and I have had lots of happy frogs - and even newts now. I did have one frog that got either a water imbalance or dropsy last year - and am not sure if it recovered or died.
Has anyone else experienced this? And what should I do? I hate the thought of having to resign myself to a frogless pond.

Tobyh · #2 (**permalink**) 26-07-2009, 01:58 PM

Sorry I can't help with your question here but I am having a similar problem.

My pond is only a few months old (beginning of May) and although life abounds (including plenty of newts and Efts) the tadpoles which were rescued from a pond being rebuilt were doing fine but now I can't see any - they developed legs but not once did I see any froglets or anything leave the pond? They did seem pretty healthy otherwise so not sure what happened - maybe something similar?

TobyH

Kayleigh · #3 (**permalink**) 26-07-2009, 02:08 PM

You wont always see them leave the pond,
Mine left overnight as I saw a couple leaving but I have only seen the odd one round the garden..
I have lots of hiding places for them just because you don't see them doesn't mean they have died.

mart1n · #4 (**permalink**) 26-07-2009, 06:28 PM

Wow, I just saw your post, please see mine , a couple places up. This looks serious. I started the year with a record amount of tads but they didnt gain weight and all died. Ive been finding dead adult frogs around the garden too.

Kayleigh · #5 (**permalink**) 26-07-2009, 07:04 PM

You need to get in touch with these if you think there is disease or finding lots of dead frogs..

Froglife - conserving native frogs, toads, newts, lizards, snakes

frogplate · #6 (**permalink**) 26-07-2009, 07:17 PM

We have been seeing a similar problem in the last week or so. Earlier in the year we had to build an emergency pond for the frog spawn laid in our decorative pond. Our larger pond snails where working their way through the spawn at an enormous rate.

The 'trug' pond is very small (27 litres) and we have had to actively manage the water quality very carefully. Despite this we've had about 200 graduates hop away into the undergrowth - some specially planted for the froglets.

We now have about a hundred tadpoles left in the pond and many seem to have stopped developing. Some have grown very large, but have not developed back legs. Others seemed to have stopped developing some weeks ago and are getting no larger. One has developed front legs but the back legs are not fully developed - they are the same size as the front legs.

In some species the froglets can emit pheromones into the water that slow the development of other tadpoles. Does this happen in the Common Frog? I've not heard of it, and we have quite a high rate of water change due to the low volume of the pond.

I wasn't too worried about this, I assumed this was par for the course, but this evening I found six dead froglets at the bottom of the pond. These were fully developed with tails fully absorbed, bodies about a cm long. No obvious signs of disease in the froglets or the adults in the big pond.

Any thoughts? Could possibly be froglets went back into the pond and failed to find their way out and drowned. There is only one part of the pond edge with a shallow ramp and they can be remarkable dense at finding it sometimes.

amanda berry · #7 (**permalink**) 26-07-2009, 09:19 PM

Thanks for all your posts. We haven't seen any tadpoles developing at all - not even the beginning of back legs, but some of the tadpoles HAD grown to a fair size. I was surprised not to have seen any little froglets, but was beginning to convince myself it was too early. I think my ponds are fairly healthy.

After every thing you have all said I have just been to have a torchlight inspection - which is sometimes easier - and I found about a dozen tadpoles - one of which had some very very tiny back legs developing. I also found one eft. But from the amount of tadpoles I started with, this doesn't seem right. I haven't seen a froglet for a couple of years now.

And I couldn't see any tadpoles at all in the smaller pond. There are lots of shrimp like things in both. Its all so miserable, I wish I knew what I could do to remedy the situation. I'm tempted to dig another pond well away from the others and see what happens next year.

amanda berry · #8 (**permalink**) 26-07-2009, 09:36 PM

Me again.
I have just looked on the Frog Life website (as advised!, thank you kayleigh). I am now concerned that I might have too much pond weed making the pond too dark. I will carefully remove some tomorrow and try and keep it under control. It may be a matter of waiting for next year to see if this makes a difference.

frogplate · #9 (**permalink**) 26-07-2009, 09:54 PM

Quote:

We haven't seen any tadpoles developing at all - not even the beginning of back legs

That could be due to the water being contaminated with an insecticide. Some nicotine-based insecticides have been found to interfere with the uptake of iodine in the tadpole's thyroid and this can effect the rate at which they develop. Chlorine has a similar effect, which is why it is important not to expose tadpoles to water straight out of the tap. Leaving the water to stand for 24 hours allows the chlorine to evaporate off. (We top up the frog pond from our main ornamental pond, and then top that up from the tap - the goldfish don't care about the chlorine).

Cheers,

Frogplate
trugpondfrogs

amanda berry · #10 (**permalink**) 27-07-2009, 08:13 AM

thanks frogplate, that makes sense. Not sure where insecticide will come from but I can and will be more diligent in my topping up - both ponds are frog and newt ponds, and I do use a hose. I won't do that any more.

I felt very jealous reading your blog - we used to have so much frog and froglet and eft activity in our ponds. We really miss it. My neighbours all seems to requiring cats which I am sure won't help should we ever get the pond balance right again (and if they haven't eaten all the parents). Also, we have fox cubs taking up residence in the compost heap - a favourite hiding place for the adult frogs.

Off to trim out some weed now to see if more light will make a difference. . .