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VIE Marking of Tadpoles

By on February 15, 2011 in Uncategorized, EDGE Updates, EDGE Fellows, Amphibians, Ghost frogs

The latest update from EDGE Fellow Werner Conradie.

Hewitt’s Ghost Frog (Heleophryne hewitti) was considered critically endangered, with a declining population. This was due to the fact that big fires and floods caused many of the streams to silt up. Big floods in 2007 cleared the streams from al lot of these silt and improved the micro habitat. The fact that tadpoles are doing well and that a new population was discovered in Cockscomb (which is in a pristine area) led to downgrading its IUCN status to Endangered in 2010.

For the last 20 months I’ve been marking tadpoles with the Visual Implanted Elastomer (VIE) markers to record their numbers and breeding cycles. The transect consisted of a 30 meters, in which I collected all tadpole I could find and marked them. See the following video on how I go about marking tadpoles.

[flashvideo filename=Videos/Ghostfrogmark.flv /]

In total I marked over 700 tadpoles, with 44 recaptures (see figure 1). Normally the tadpole numbers is below 50. In the month of September adults start calling, mating take place and around 100 eggs are laid. This explains the high numbers of tadpoles collected in January. In the month of February and March the bigger tadpoles of the previous season start metamorphosing, explaining the slow decrease in tadpole numbers by October. It is expected that with the next marking in December the tadpole numbers will increase again.

To support the work of EDGE Fellow’s such as Werner you can donate to EDGE here.