Local coordinators supporting international chytrid research in Madagascar

by Jeff Dawson - July 25, 2018

It is led in-country by Tsanta Rakotonanahary and Serge Ndriantsoa, to whom Durrell provide managerial, logistical and personal development support. A key project aim is to help build and develop networks for amphibian conservation in Madagascar. Research and conservation activities related to the amphibian fungal disease chytridiomycosis are coordinated through the Chytrid Emergency Cell network which this project helps support.

In April 2018 Tsanta and Serge helped facilitate and participated in an international research project “Evaluation of chytridiomycosis affecting amphibians of Madagascar”, led by Professor Mat Fisher from Imperial College London.  This project aims to isolate the strain of Bd chytrid fungus presents in Madagascar as part of a global study. This blog tells what they did other there.

After the various administrative formalities in the region authorities of Marovoay and Majunga, we were able to start working. The site of the field work was Ankarafantsika National Park, located in the north-west of the country. Ankarafantiska, also known as the kingdom of the birds, is dry forest habitat with several lakes that are considered sacred by the local people. These lakes are home to various endemic fauna and flora and used to be the tomb of the royal family in the region.

Serge collecting tadpoles in Lake Antsahabe (Photo: Tsanta Rakotonanahary)

Our first field site was Lake Antsahabe, a small lake behind the restaurant where crocodiles are presents, yes, crocodiles. But do not worry; we didn’t compromise our safety fro science. We collected adult frogs and tadpoles to isolate the pathogen causing chytridiomycosis locally. We also found freshwater turtles: Erymnochelys madagascariensis, which is endemic of the northwest to south-west of the Big Island. Several species of frogs were collected including Heterixalus luteostriatus, Mantidactylus ulcerosus, Boophis doulioti, but the majority were the common and widespread Ptychadena mascareniensis.  Tadpoles were caught by using a net with adult frogs caught by hand. Because we did that work for several times now over previous years, we were quite used to it, so, it was not very difficult to meet our target of  50 animals for the beginning. We were also lucky with the weather, it was raining, so, frogs were active which made our job much easier.

In the following days, we visited the rice fields in and around the National Park. One of the things that surprised us a lot is the temperature in which the tadpoles in the rice fields live. Usually, tadpoles won’t survive in the temperature about 42 degrees Celsius but in Ankarafantsika, they do and they are very active.

Ptychadena mascareniensis, the most common species found (Photo: Frank Vassen. Re-used under Creative Commons Attribution 2.0 Generic Licence)

After catching frogs and tadpoles, they were brought at the laboratory facility of Durrell Wildlife Conservation Trust at Ankarafantsika for swabbing. This is done with a special sterile cotton bud, wiping it over the frogs skin, and later on Professor Mat Fisher and his team will try to grow up the Bd chytrid fungus at their lab in London if the pathogen was present. Bd chytrid attacks the keratin layer of the frogs, so, we swab the buccal disque for the tadpoles and the belly, legs and palms for the adult. These parts of the animals are the most keratine layers of their bodies.

As a reminder, chytriomycosis is an infectious disease affecting frogs and salamanders and already causing massive mortalities worldwide. Although the Bd chytrid fungus has been found in Madagascar the disease itself has not yet been declared so this work is important in identifying the strain present and potential risk to Madagascars unique frog fauna. Professor Mat Fisher said that, Ankarafantsika has been his favourite site in Madagascar so far, given the facilities there. The laboratory is a few steps from the field, the amphibian collection sites are nearby and the people working there are so welcoming and helpful. If the lab work isolates any fungus we will go back there again soon this year to collect more samples.

Note: Results from the study looking at global chytrid strains, to which this work will add, has recently been published in Science  – see Blog published 31 May 2018 ‘chytrid special’.