00:0130 years ago, these frogs would have been super abundant along the creeks and the streams
00:05of the northwest slopes area.
00:07I love those rocky riverine habitats, and they would have been in large numbers and
00:12played a really significant role in the food web.
00:15But unfortunately, they've been hit by a number of different threats, including disease,
00:19including different features of the habitat, for example, stream drying, weeding curfew
00:25and so forth.
00:25And unfortunately, in 2017 to 2019, that really severe drought we had was the final straw
00:31for a number of the different creeks and catchments throughout that northern area.
00:34And unfortunately, they dipped out towards the end of 2019 and the start of 2020.
00:39Yeah, and they're cute little fellas, aren't they?
00:41They're beautiful little frogs.
00:44And so how long has Taronga been involved in the breeding program?
00:49Yeah, sure.
00:50So for the northern populations, since 2019, right towards the end of 2019,
00:56the alarm was raised by a local ecologist, Phil Spark, who'd been doing surveys of them
01:00and realised that their numbers had dipped so low in the drought that they'd become critical.
01:04As a result, the alarm was raised with our partners in DQ, and they engaged us.
01:10And within a matter of weeks, we're up there, I guess, doing a salvage operation,
01:13trying to collect whatever's left because there was a real risk that the species was going to go extinct
01:17in that northern part of its range during that summer.
01:20And we're lucky enough to collect 60 frogs to start a genetically kind of managed
01:25and broad insurance population here at Taronga Zoo.
01:28And are they easy enough to breed?
01:30They are, fortunately.
01:31We work with a few species of frogs, and some of them are very easy to breed.
01:35Some of them aren't so easy to breed.
01:36And the burrolong frog is one of the easier ones.
01:39We've bred from mostly initial founder animals.
01:41And those that we haven't bred from, we've actually got a sperm prior preservation project here at the zoo.
01:46So we're able to collect sperm and bank it from those that didn't breed.
01:49But we've bred them quite well.
01:50We've bred large numbers.
01:52The 1,200 that we released just recently were from 10 different clutches.
01:57So we got, like, lots of genetic representation in the big cohort of frogs that we released
02:01along creeps in that system.
02:02And, yeah, so what's the turnaround for breeding?
02:06Like, how long does it take for them to give birth and how many do they give birth to?
02:11Yeah.
02:12So for the burrolong frog, life's a very shortened process.
02:15They only live for three or four years in the wild.
02:17So they mature quite quickly.
02:18Males are mature within a year, females within two years.
02:21And some of the frogs that we released the other day, even though they're only three
02:24to four months old, they've grown significantly.
02:27And some of the males on the way up there in the car, we can hear them falling from their
02:30enclosures in the car on the way up.
02:32So breeding will happen quite soon.
02:34The females won't be mature until next season at the earliest.
02:37So hopefully from next season onwards, we'll start to see eggs laid in the streams,
02:41start to see tadpoles.
02:42And hopefully come January, February, we'll start to see little metamorphosing frogs
02:45emerging from the edge of the streams.
02:47Yeah, cool.
02:48What's it like for you to be involved in something like this?
02:50Oh, it's amazing.
02:51Yeah, it's amazing.
02:52Here at Taronga, in the Recton and Amphibian department, we work with seven different species
02:56that are either critically endangered or extinct in the wild.
02:59And each of those species, we breed in large numbers.
03:01We do different reintroduction trials and different strategies to try to re-establish their
03:05populations.
03:05And the Borulong Front is one of those really rewarding ones because the one trial population
03:10we've done so far at a place called Mullum Mullum Creek, up in that region, has worked really
03:14successfully.
03:15As the trial released over a few years, the frogs survived quite well.
03:18They bred quite readily across the whole transect of the stream that we're working on.
03:22And now their offspring are actually starting to call on the stream.
03:25So it seems like the reintroductions so far are working quite well.
03:28So this year we're really ramping up the numbers and spreading it out to new parts of the spring
03:33where they disappeared during that 2019 drought.
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