Destiny and 239 Tadpoles
June 15, 2021 2:57 PM   Subscribe

A few days ago, I scooped up some frog eggs. Now I have at least 239 Cope's gray tree frog tadpoles.

Perhaps the question is obvious,... I can probably raise 40-60 ish tadpoles to the froglet stage, when I would release them. One knowledgeable person suggested keeping them in a big basin outside, and I might do that, but it seems suboptimal. They are growing very quickly.

I probably shouldn't just release them into a pond; one reason is concern about spreading amphibian pathogens. There is a pond near their origin, though.

- These are homeless tadpoles, not kidnapped tadpoles - their origin puddle is gone.

- I'm doing pretty well on the mechanics of taking care of them, feeding them, knowing how many I should keep in a given space, and the fact that they aren't protected but I'm only supposed to have <= 25 amphibians at one time in North Carolina.

- Every day they get bigger and it's harder to keep the water clean; I've got a while before it's impossible, but it's work.

- If anybody in/near Durham/Chapel Hill NC wants to take on some of these to help rear them up, definitely contact me.

Some attrition is to be expected, of course, but they seem pretty perky as long as I don't stress them out too much.

Left in the puddle, they all definitely would have died. The next day there were no eggs left. Looking down into the puddle, phone camera maximally zoomed, I swear there were teeny tiny tadpole skeletons all over the bottom. I also saw happy water spiders, ants, predatory diving beetles, and some new white spherical floating egg cases. The circle of life is hard on amphibians.

School is out, so biology teachers are probably not an option. I'm not sure how to proceed.

I already contacted the Piedmont Wildlife Center and NC Herpetological Society.
posted by amtho to Science & Nature (14 answers total) 1 user marked this as a favorite
I probably shouldn't just release them into a pond; one reason is concern about spreading amphibian pathogens. There is a pond near their origin, though.

I mean, they got from the pond to the origin somehow, right? It's unlikely that you would be spreading anything that frogs wouldn't spread themselves.

Naturalistically, I think you have little/no responsibility here. Or rather, taking them from the puddle away from the hungry spiders/ants/beetles was the ethical crime. The most proper thing is probably to return them to their puddle. A nearby pond would be fine.
posted by bbqturtle at 3:09 PM on June 15 [11 favorites]

Recreational centers or science museums?
posted by firstdaffodils at 3:17 PM on June 15

If you're on Facebook and can find some local homeschool groups to tell about it, they may want to raise them. Another place to try would be a local land trust, since they are invested in restoring native habitats.
posted by xo at 3:23 PM on June 15

I agree with bbqturtle. Unless someone else came along and dumped that frogspawn in the puddle, those tadpoles would already be part of the local ecosystem, so technically speaking you wouldn't be contributing anything "new" here. The parent frogs probably saw the puddle and mistook it for the nearby pond. By helping them into a larger habitat, with a larger range of predators/prey, they will be a bigger part of the local system than if you reared them alone.

Frogs spawn en masse because the majority of those tadpoles are not supposed to survive, so the frogs play the odds to make sure at least some of them do. This is natural and expected. They have many predators who depend on them for food (fish, beetles, spiders, birds, other amphibians, etc). If you try to raise all of these tadpoles to adulthood, you'll be creating a much larger ecological problem for your local area than if you returned them to their natural habitat.

Looking it up, those frogs are native to NC and this is their home. Returning them to the pond won't spread anything that's not already there.

Your kindness is commendable but ultimately these frogs and your local wildlife would be best served if you brought them home to the pond.
posted by fight or flight at 3:25 PM on June 15 [14 favorites]

I have raised a lot of tadpoles. You want to raise about 10 tadpoles. The bigger they are the more they eat and the more they poop.

You want to release the extra ones into a vernal pool. They lay them in vernal pools because they need to be someplace where there aren't fish and other things that make them an easy lunch. They then -- when adults -- go BACK to that same vernal pool to find a partner.

By putting them in the right spot to are helping them be able to have offspring that survive.

DO you have a local group like Audubon? We have been mapping our vernal pools and you may be able to find the one that frog was aiming for.
posted by beccaj at 3:40 PM on June 15 [6 favorites]

Response by poster: Gray tree frogs don't spawn in ponds, so putting these tadpoles into a pond wouldn't be returning them to a natural location, and they couldn't really spawn there next year, which might be why my contact didn't encourage that. Their vernal pool, and nearby pools, dried up quickly

The 'big tub on my deck' idea came from someone with the local herp society and another wildlife org. He doesn't seem to favor putting them into another location -- the pathogen issue is a big one for amphibian lovers. Chytrid in particular is nightmarish.

------ the local vernal pool situation is not ideal -------

It's been unusually dry this spring. The vernal pool/puddle was large, but it's gone. I found a pool about 20 feet away in the woods after the last rain -- and I looked for more -- but it's gone too. I think the water's being absorbed quickly because the ground is dry.

There was an amazing vernal pool nearby me this week; I heard Cope's grays AND something that sounded like a bunch of tiny sheep -- turned out to be eastern narrow-nosed toads -- and I saw a blue crayfish! but that was just mud two nights ago.

Normally, there's a vernal pool adjacent to my building. I don't see water there now.

It's not a huge drought or anything -- we were "pre-drought" or something --just not easy to find the usual spots, including their spot.
posted by amtho at 4:25 PM on June 15 [1 favorite]

I'd second looking for homeschoolers/bored kids perhaps on some social media like Next Door, Craigslist, or Facebook. On Saturday my kids and I went down to a local river and saw tons of tadpoles and ended up bringing a bunch home. On Sunday we returned all but 5 of them because what were we going to do with that many tadpoles? We're keeping them in a large storage container outside and two of them have already grown arms and legs and it is really neat to see them change by the day.
posted by any portmanteau in a storm at 5:08 PM on June 15

Another point of note is that all the other critters that eat tadpoles aren't in quite as critical decline as amphibian populations are.


Maybe refill/ flood their natal vernal pool and return some? That would mimic a timely natural rain that could have saved (some of) their asses.
posted by SaltySalticid at 5:54 PM on June 15

Coming back to this after your update -- I guess I don't really understand how saving the tadpoles and raising them yourself/giving them away to be raised to adulthood and then presumably released into the wild again will be beneficial to the ecosystem, if that is your ultimate goal. Having that many adult frogs flooding the local area will surely create an instability in their environment, unless you're committed to monitoring their release with the local herp society.

I agree with SaltySalticid. If you want to keep or raise the frogs for educational reasons or for a project then by all means keep a small amount (as suggested) and the rest you could return to a vernal pool which you can fill/monitor if you're worried that it will disappear.

Ultimately I think you are putting a lot of responsibility on yourself to save these animals, which is commendable, but there also needs to be a degree of letting nature take its course here, both for the sake of your own capacity and the capacity of the organisations you'll be relying on to take on hundreds of frogs. It's sad to know that many of the tadpoles probably won't or can't survive due to predators, bad weather, or bad luck, but tipping the balance too far in the other direction might end up being harmful as well.
posted by fight or flight at 5:27 AM on June 16 [1 favorite]

Response by poster: Another update: I'm not sure how many have died so far, but it's a lot, despite my extreme efforts and frequent, gradual, oxygenated water changes, and many additional containers. The ecosystem is in not in that much danger from frog overrun.

Some of that is doubtless from overcrowding (which I'm addressing) and not enough oxygen.

However, I'm also keeping an eye open in case they have a parasite I just learned about. Ugh. Such weird deaths. I'm finding many of the dead tadpoles have giant white stomachs. I'll keep an eye on this in case it turns out to be a serious issue.

I'm removing dead ones as soon as I find them, and giving them a chance in a holding cup in case I misread the situation. They are in six separate containers which might help isolate any problem -- if it can be isolated -- and I may divide them further.

The rest seem to be doing pretty well, eating boiled lettuce and swimming around, enjoying some surface leaves, but who knows what will happen.
posted by amtho at 10:05 AM on June 16

What is your question?
posted by tiny frying pan at 5:31 AM on June 17 [2 favorites]

I've kept tads (in Chapel Hill NC), and here is what I've had luck with:

-Shallow container/basin outdoors (I used 3" deep rectangular plant trays with no drainage holes) that I topped off periodically with the hose, and potted aquatic/wetland plants in the tray so that the plants were in somewhat flooded conditions. I had luck with Colocasia, which grows fast and seemed to keep the water clean despite tad poops and dead tads. Colocasia may be an invasive plant in the Southeast, so use with extreme caution or find native wetland plants.

- deeper container (a pond liner around 4x3', and ~12" deep) that I installed outdoors, sunk into the grade of my soil. Again, I used potted plants atop a layer of bricks (because it was so deep). Tall terra cotta pots with native NC plants (buttonbush, lobelia, lizards tail among others) worked well for this, and the tads ate the algae that grew on the pots below the water line. I used an aquarium pump to provide some water agitation/oxygenation. Mosquitos were an issue, I tried to keep up with mosquito dunk dosages. Fifth Season in Carrboro has a good supply of tall terra cotta pots FYI.

In both set-ups, I believe plants were key for stabilizing and improving water conditions. I added supplemental food (algae wafers meant for aquariums) sometimes but it seemed redundant.
posted by Drosera at 8:32 AM on June 17

Response by poster: Thanks for the first-hand account from my area, Drosera! Unfortunately, I'm in a condo, and my deck area is too hot and small to make this work. Maaaaybe I could put a small something to hold water underneath a planter box, but that doesn't really seem like a good idea.

I think I have to do this indoors. I'm setting up a shallow aquarium - 20x12" - and I might be able to do a second one later; if I need to keep some elsewhere I guess I can do that.

Let me know if you want to foster some tadpoles :) They really need to be observed and then released in the same area, though, I think.

Thank you all for the information! It's so nice to feel that I'm not totally alone in this ill-conceived undertaking.
posted by amtho at 11:07 AM on June 17

Response by poster: Current count: 130. Frogs go for quantity over quality, so I don't think I'm doing too bad.
posted by amtho at 9:41 AM on June 19

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