If you have set up a frog pond properly that is well used by the frogs, you will soon find yourself with more tadpoles than you can handle. Many species of frogs breed in large numbers to compensate for the high mortality of their larvae. In other words, it is a natural process for a certain number of tadpoles not to survive to metamorphosis. However, many more tadpoles could survive if they were distributed over more sites of permanent water, such as new frog ponds or those which haven't attracted any amorous adult users.
On the one hand, tadpole distribution can allow more tadpoles to survive and it can be used to reintroduce species to areas where they once were. On the other hand, distributing tadpoles is an excellent way to quickly spread diseases that can wipe out as many frogs as what were saved in the first place, if not more. A lot of folks are under the impression that if they don't have chytrid fungus in their area, then they don't have any disease problems. WRONG! There are many other diseases besides chytrid and many are being moved around by people and the trade.
In January, 2003, three batches of awful looking tadpoles from three households in the suburb of Redlynch, Cairns were turned into us for evaluation. They were off colour, sluggish, not eating well, and some had bent tails. They were dropping like flies, so to speak, and we had them virus tested by the School of Virology and Immunology at James Cook University. The researcher found a virus using sequencing but he was unable to identify the virus. We originally dubbed this problem the "Redlynch" virus but now refer to it as a malformation caused by chemicals spreading through waterways. From what we've seen since and the rate of spread that is occuring with this aquatic problem, it is obvious that there are two very effective ways that this problem can be carried from place to place: the first is moving tadpoles around and the second is people who do surveying in the field and do not use disinfection procedures.
The presence of an aquatic virus that kills nearly all the tadpoles in a body of water and/or sits dormant in those that metamorph for later activation is a serious issue. Likewise, the damage caused by a chemical that causes genetic damage and 100% death rate of all offspring in a cluth is incrementally more serious! This is especially because this problem does not make its presence known until the later stages of tadpole development. Everything seems fine until the back legs are at least halfway grown and then all heck breaks loose!
Viruses have a long dormancy period - up to two years but some are much longer. Psitticine Beak and Feather Disease and Feline Immunodeficiency Virus (both rampant in Australia) have dormancies up to five years - so tadpoles and frogs in your garden can be carrying a virus (or genetic damage) without showing any symptoms. When tadpoles and frogs that have been exposed become stressed, which is the case at metamorphosis or during the dry season/drought, then the virus is triggered and spreads to other frogs. As soon as those sick frogs go to water, they can spread their pathogens into the water where all the tadpoles can pick it up.
Aside from the problem of spreading disease, regulations in QLD changed during 2004 making it illegal to relocate tadpoles without a rescue permit.
We recognise that rescuing and distributing tadpoles is a tool that can assist the restoration of frog populations on a local level, but we are also extremely concerned about the spread of disease, especially a ranavirus or the malformation problem. We would like to find a sensible, middle ground to a complex problem. Until we hear otherwise from the researchers, we are making the following suggestions concerning the movement of tadpoles anywhere, not just where there are regulations. These suggestions are subject to change based on new findings on the spread of disease in FNQ.
This includes tourists who are visiting Far North Queensland for holidays - do NOT collect tadpoles here to bring home with you. The most serious amphibian diseases we know of so far are aquatic so keeping to your own catchment might help prevent an aquatic pathogen from spreading throughout a new catchment. If you do not know what area makes up your local catchment, contact your local council or Integrated Catchment Management community group.
(such as bent tails, multiple limbs instead of one, lumps or growths) or tadpoles dying off in moderate or large numbers in your pond or aquariums. There are a few reasons why tadpoles would die off in numbers and one of them is disease but bad husdandry or toxins can also cause deaths. Another time when large dieoffs would occur is at metamorphosis and, if this is seen, the dead tads/morphs should be frozen or preserved by a vet for testing later. If you have tadpoles with the problems listed above, please contact us. If you are close enough to us, we will ask you to turn in all the remaining tadpoles so that we can raise them under optimal conditions and document what problems they are having.
This applies to national parks as well but could include reserves or even private land. You might be able to find out where rare frogs live through frog websites or Australian residents can also use the Frog ID app to search for all the frog species at a given site. If any of them are rare, then you don't want to release anything in those locations.
Each species should go to the right habitat and the right enclosure. If you have more than one species breeding in your pond, how do you know which species the individual tadpoles are? Is it a species that needs to be fished out of the tank it has been put in or will it be able to get out of the water without falling back in and drowning? Is it a burrowing species that needs pliable soil to burrow into or a tree frog that needs lots of surrounding vegetation? Are the tadpoles being moved to outside their known range (such as Striped Marsh frogs being moved any further north than Cairns)?
It will also be best for those receiving your tadpoles to raise them in aquariums and NOT release them directly into their pond. Tell the recipients to let you know if there are any die-offs or deformities so that you can stop giving any more away.
If you can't find any other frog pond owners in your suburb to take some tadpoles, you can set up a fish tank or two and raise some tadpoles yourself so that more will survive.
If you're not sure about any of this, please contact us to discuss it before you distribute any tadpoles to the wild or to anyone else!
Receiving tadpoles from another pond or the wild
If you should acquire some tadpoles (best to check the laws in your area first), each batch you receive should be handled separately from any others and be kept at least a metre (3 feet) of space apart between each container. Put labels on each container with the location the tads came from and the date. Do not put them into your pond but rather raise them in aquariums or other containers.
All containers should have been disinfected first with whatever product you choose (not bleach) and then wiped down with 10% povidone iodine (betadine) and rinsed very well before using for the tadpoles.
All tadpoles should be handled as if they are already diseased. They might look good when you acquire them but this could change over time. If you have been handling them properly to start with, then you won't be spreading disease. If you haven't handled them according to disease control methods, then it is likely you will have cross-contaminated all the tadpoles you have by the time you discover there is a problem - and that would be a tragedy.