Golden Mantella Released from Captivity to Help Wild Population

Mantella aurantiaca, the Golden frog is an amphibian species endemic to Madagascar. It occurs only in a very limited area around the town of Moramanga including the Torotorofotsy wetland near Andasibe. Due to its restricted distribution, the Golden mantella is considered Critically Endangered. The species is threatened by habitat loss caused by human activities. Also, the amphibian chytrid fungus might put it at risk.

To mitigate population declines and the threat of extinction, assurance populations caught from three sites on the footprint of the Ambatovy nickel and cobalt mine were established in captivity by Mitsinjo in 2012. In 2013, a reintroduction programme was prepared and the breeding centre started to raise an additional number of frogs with a future release in mind.

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Adult Golden Mantella at the Mitsinjo captivity breeding center

The preparations of this first release trial began in 2016. Four receptor sites were selected and restored by Ambatovy in collaboration with the University of Antananarivo. The sites are in protected zones close to the ponds where the animals belonging to the original founder stock had been caught. The release took place on three consecutive days from 26 to 28 April 2017, following disease screening to ensure captive stock was in good health. Golden Mantella produced in captivity by Mitsinjo, including more than 1,000 larvae and frogs, were taken early in the morning and transported in plastic boxes from the centre to the receptor sites. A soft-release method was used for adults and juveniles. This means that the animals were not immediately released into the natural sites but acclimatized to wild conditions by keeping them in protecting cages. Tadpoles at earlier life stages were released using the hard-release method, directly into the closed habitat. Ambatovy and the University of Antananarivo are conducting monitoring of the frogs and larvae produced by Mitsinjo.

A Mitsinjo technician at the breeding centre assists Ambatovy staff move frogs from a terrarium to containers for transport:

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Plastic containers for transporting frogs to receptor sites

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The team from the University and Ambatovy come to collect frogs at the Mitsinjo captive breeding center.

The official launch of the reintroduction of the Golden mantella was organised on 19 May 2017 in Andasibe. 72 people participated in the seminar, representing the Ministry of the Environment, Ecology and Forests, local and regional authorities, environmental organisations and the Ambatovy mining company. The member of Parliament elected from Moramanga opened the seminar officially. There were also many journalists who were interested in the release. A press conference was held on 18 and 19 May.

The frogs have been monitored after the release and the results look promising. The whole release programme will last two years. It is implemented in close collaboration between the stakeholders which include the General Directorate of Forests DGF (Direction Générale des Forêts), the IUCN SSC Amphibian Specialist Group Madagascar, the Biodiversity team of Ambatovy Minerals, Association Mitsinjo, Madagasikara Voakajy, and the Universities of Antananarivo and Mahajanga.

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Mesh field enclosure for soft release of tadpoles constructed by the Biodversity team of Ambatovy and the University.

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Recent Achievements in Conservation Frog Breeding

By Sebastian Wolf

In early 2016 Mitsinjo’s frog team brought several new, locally occurring frog species into the breeding facility, some of which had never been kept in captivity before.

After acclimatization we were curious when or if they would start breeding. Natural reproduction period of most local frogs starts with the first rains in December or January, yet the 2016-2017 season has been different due to the fact that rain was largely missing until now. Fortunately, Mitsinjo’s captive frogs did not care about this dry “wet season” as they continued to overwhelm us with eggs. All species in our facility except of one at least produced eggs and tadpoles and the first young tadpoles have successfully metamorphosed into froglets by now (sometimes incredibly tiny creatures like the one in the picture, an already 3 week old Platypelis barbouri which is roughly 4 mm in size).

Platypelis barbouri was one of the new species Mitsinjo acclimated to captivity in 2016.

Platypelis barbouri was one of the new species Mitsinjo acclimated to captivity in 2016.

There are two crucial issues in frog breeding: finding out which climatic and microhabitat conditions trigger reproduction, and caring for – often plenty – of froglets that need large quantities of small prey insects. Small changes in cage design (what scientists and zookeepers call structural enrichment) finally did the trick with Mitsinjo’s frogs and immediately resulted in egg-laying.

Having the world’s first captive bred animals of a certain species is exciting, yet not the end oft he effort. Aside from successfully raising froglets to mature individuals once, the next step should always be to breed the captive frogs into the next generation(s). This already worked out with our flagship species, the Golden Mantella where some of our second generation captive animals will soon be released at ponds within their natural distribution range. Among the species we bred for the first time were some elusive microhylids, a conspicuous bright-eye treefrog and a mantellid frog that has no free-swimming tadpole stage but where eggs develop into froglets inside the egg capsules – we call this the low-budget frog as it does not need to be fed during its larval stage.

The golden mantella (Mantella aurantiaca) population at the breeding facility helps ensure the species survives in the wild.

The golden mantella (Mantella aurantiaca) population at the breeding facility helps ensure the species survives in the wild.

Looking at the recent efforts raises our hope that we are capable of breeding other endemic species as well, in case of any emergency event that needs immediate rescue or mitigation action. Aside from husbandry experiments that we conduct to steadily improve care and maintenance protocols, the next big thing will be running breeding trials with more stream-breeding frogs as they are an important part of the frog fauna in rainforests here and can be quite demanding in some aspects.

Raising healthy  frogs also requires vitamin and mineral supplements and proper food for tadpoles. Two companies thankfully provided free food and minerals for this breeding season (Aquarium Muenster and Keweloh Animal Health).

What do the tadpoles of little brown frogs eat?

We’re very pleased to be able to share some results from our amphibian captive breeding program with you this month. The full article can be found here.

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A juvenile Mantidactylus betsileanus frog from the study.

Published in the journal Alytes, our members worked together to investigate what is the best diet for the tadpoles of the Madagascar Betsileo Frog Mantidactylus betsileanus. We found a locally available shrimp and powdered spirulina aglae to work better for rearing the tadpoles than mustard greens.

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A tadpole in the study just about ready to complete metamorphosis.

Although the frog is not highly threatened, the information gained will help us develop future ex situ conservation programmes for species at risk that we have yet to learn how to keep in captivity. Perhaps just as importantly, the study helped our team of five amphibian technicians develop scientific expertise, and being able to answer biological questions using the scientific method allows us to make informed management decisions, not just about frogs but about the environment as a whole.

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Terrariums at the breeding facility that house the frogs.

Amphibian Chytrid Fungus in Madagascar

For the first time, the amphibian chytrid fungus (Bd) has been found in wild Madagascar amphibian population. This recently published research paper summarizes the results of a tremendous collaborative effort in chytrid research in Madagascar. Association Mitsinjo is proud to have been a part of this study. Mitsinjo members were present during the first discovery of chytrid in Madagascar in the Massif du Makay and subsequently led the regular sampling of amphibians for chytrid in the Andasibe region.

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As alarming as the detection of chytrid in Madagascar is, no mass mortality of amphibians appears to have been associated with it so far.

In a best case scenario this might indicate a previously undetected endemic type of Bd and/or hint at a natural resistance of Malagasy amphibians against chytrid.

In a worst case scenario, this might only be the early stages of a devastating epidemic with the potential to wipe out many of Madagascar’s unique frogs.

Stay tuned…

Links and more information:

http://phys.org/…/2015-02-amphibian-chytrid-fungus-madagasc…
http://www.amphibians.org/ne…/bd-madagascar-franco-andreone/
http://www.amphibians.org/news/bd-in-madagascar-reid-harris/
http://www.amphibians.org/news/bd-madagascar-molly-bletz/
http://www.bbc.com/news/science-environment-31645122