RAUK - Archived Forum - rescued tadpoles

I had brief communication with Gemma yesterday about this, but really need more information please!

My sister's garden pond became home to frogspawn for the first time this year, and she was horrified (she's not interested in active conservation). She has koi in the pond and was going to clear out the spawn and dump it.

When we went to look at the pond, the spawn had hatched, and the tadpoles had gathered into a mass of jelly and weed in the middle of the pond.

I contacted froglife (on Gemma's recommendation) and was told not to relocate the spawn to a nearby woodland pond because of the risk of redleg, but to remove it from the pond and grow the tadpoles on a little before returning them to the pond (once they were grown big enough to better avoid the fish). I was told that they would eat the algae from pondweed for a while, then to feed them fish food until they had grown.

Gemma replied to my pm while I was "rescuing" the tadpoles from the pond, saying that they will need large amounts of livefood (somewhat contradicting froglife on the fishfood issue!). 

I now have about 10 litres of hatched spawn in netting-covered bowls in my back garden, with a plentiful supply of algae-covered weed in with them.

Ok, now to the questions!  I am aware of the problems of deoxygenated water, so am intending to refresh the bowls regularly. Would boiled/cooled tap water be sufficient for this? How often will I need to add/replace water?

What sort of livefood will I need, in what quantities, when will they start needing livefood, and how often will I need to feed them?

And my biggest problem now is this - my sister has been told that the frogs will grab onto the gills of her fish and suffocate them, and despite my reassurances, she now flatly refuses to have the grown-on tadpoles back in her pond.  What on earth am I going to do with any of them that survive and grow?  I'm beginning to wish that she hadn't told me about them at all!

Any advice will be VERY gratefully received!

Hi JaneW,

Firstly, I was a little surprised Froglife advised you to grow them on yourself, I didn't really consider it an option, but it's not as bad as it might seem!

Firstly, de-oxygenation of the water isn't such a problem in bowls, which have a large surface area, just don't leave them in full sun, and not too many plants as the tadpoles grow larger. It should then be sufficient to top up the water with fresh just to keep the level up in the bowl. The water does not strictly need boiling, standing for 24 hours is sufficient to de-chlorinate the water, I have never had a problem with water straight from the tap with tadpoles of Common Frogs.

On the food issue, they are little eating machines, they will eat anything from dried fish food to dead vertebrates. My own preference is for chopped up earthworms and crickets, as they do not foul the water like fish food, and are a little more natural. (they don't have to be live, dried crickets are available)  They become meat eaters at about 1 - 2 weeks depending on the temperature they are kept at.

With amounts, you will soon see how much they need, as they grow and become free swimming add a few bits of food and see how quickly it goes. Using worms I just add a few chopped up ones and add more when it is all gone.

Your sisters worries are unfounded, the danger of suffocation of the fish is past, this occurs during the spawning frenzy when an adult frog may accidentally grab a fish thinking it to be another frog, your little tadpoles really do not present this risk! (This only occurs very rarely)

If she insists, grow the tadpoles on to little frogs, then they can be released without putting them back in a pond, just somewhere quiet and safe with plenty of cover.

If anyone else has anything to add, I am sure it will be appreciated

Thank you, Gemma!  You've certainly reassured me a little now, I'm sure I can cope with the feeding issue, as I feed the wild birds in my garden with livefood at this time of year anyway, I can always appropriate the earthworms for the tadpoles!

My sister is adamant that they are going nowhere near her pond anytime in the future, so I have to work on that reality. I do not have a pond in my garden, although it is a mature garden with plenty of shrubbery cover. Would I be able to release them here? Hmm... maybe I'll build myself a pond!  I am concerned with the redleg issue, if I can't release them where I am, what are the risks of releasing them into a woodland nearby me (about a mile away, maybe 2 miles away from their original location)?

Yes, anyone else please chime in too! I'm open to any and all suggestions/advice!

Hi Janew,

Glad I could help. The advice on redleg is translocation no further than 1km from the original pond.

I see no problem at all with you releasing them in the Garden, and why not give them a pond as well! Common Frogs are living in gardens in Central London quite happily. They prefer damp margins of ponds when tiny, but can do quite well far away from water, only seeking a pond when they come to breed at 3-4 years of age. (It might be an idea to sink a bowl of water in the shrubs they can use if they like to begin with, make sure it has some plants and rocks so they can easily climb out.)

If it is any consolation, I've about 300 common frog tadpoles growing on here a few weeks ahead of yours, so any more worries let me know

JaneW

As an overview, as you are considering making a pond, if you did this sooner rather than later, you could transfer the tadpoles to this new pond which is more suitable than bowls. (They will still need feeding till the pond becomes established)

Redleg is not such an issue as the pond would be newly populated, the fear is that the disease will be spread to existing populations by translocation.

Froglife advice sheet 1 gives answers to questions about amphibians in gardens

http://www.froglife.fsnet.co.uk/FAS/1.htm

Thanks Mervyn, I will probably be able to make the pond over the next few weeks, so hopefully in enough time to be useful to the tadpoles! 

I'll keep you updated, and I'll definitely shout if I need any further advice.

Thanks David, I'll be at the supermarket tomorrow to get a stock in!

Quite a lot of them are free-swimming now, I'm going to get a baby-bath to replace the bowls I've got them in now, I think that will be easier to manage until I get the pond sorted, and have a larger surface area than the bowls too. (Thanks to Martin for that suggestion!)

Dave,

This is the plant the tadpoles I have are feeding on, I would appreciate an identification if possible.

I am interested as the pond the above sample came from is 2/3rds filled with this plant, there has been a substantial Common Frog spawning and I would like to observe the impact of the tadpoles on keeping the plant in check.

(I will take note with the protein, my own thoughts were more towards avoiding cannibalism with Common Frog tadpoles, as I have witnessed this on occasion when plenty of vegetable matter was available, but I would like to avoid undersized froglets)

Thanks Dave,

I still have a lot to learn about tadpoles! I asked about the plant as what caught my attention was the fact the tadpoles were feeding on quite intact and fresh material, leaves, stems and roots. Close observation revealed that previously intact and healthy material showed bruising after their attention, particularly the underside of the leaves.

They have now lost all interest in it, so time for a trip to the supermarket

There's a paper on tadpole nutrition in Wood frogs (Rana sylvatica) here:

http://www.podarcis.nl/downloads/2002/3/eng/Wood-frog-3-3-UK.pdf

(you might need to register here: http://www.podarcis.nl/register/register_eng.html)

The authors used combinations of soy meal and corn meal to vary protein levels, and got best results with 25% protein, using 50% cornmeal, 50% soy meal.

Personally, I use blanched lettuce (just pour boiling water over it and leave it for a few minutes) and occasional fish flakes.