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Giant salamanders - a mountain amphibian threatened by extinction

June 8, 2018

Most of people know the American bullfrog, which is already a quite impressive amphibian, reaching up to 20cm in size and something between 500 to 800g in weight. However, the Goliath frog is even bigger, reaching sizes of up to 32cm and 3.2kg of weight.

 

Photo: American bullfrog in Taiwanese Frog Farm. Dirk Schmeller

 

So, how big might then be a giant salamander? 30cm and 2kg of weight? More? Less? Actually much more. There are different species, but the tallest one is the Chinese Salamander, reaching a size of 1.8m!!! It can weight a whopping 50kg! So, that is big, actually the largest of all amphibians. Some time back, scientists found a specimen of about 200 years of age (Washington Post). So, it really can get old as well. It lives in streams in 17 provinces in the mountainous areas of the middle Yangtze, Yellow and Pearl Rivers.

 

 Photos: A Chinese giant salamander lays in the water. Robert Murphy

 

Unfortunately, the giant salamander is critically endangered with strong declines over the past 50 years due to habitat destruction and degradation, and most important consumption. The latter mainly due to the belief of traditional medicine that the giant salamanders has positive effects on human health. That belief was deduced from the fact that the species has little changed over the last 170 million years and is therefore also termed a living fossil. Just to put it in perspective: a  170 million years ago there were no  flowers and birds, nor Brontosaurus and Stegosaurus!

 

In 2004, Wang et al. (2004, Oryx) reported that since the 1980ties 14 nature reserves, with a total area of more than 355,000 ha, have been established for the conservation of the Chinese giant salamander. These numbers have since grown, but little has changed for the the giant salamander. It may have even made things worse, as a new study actually suggests that the Chinese Giant Salamander is not one, but five different species (Yan et al. Current Biology). The release of captive bred giant salamanders without knowledge of their genetics has likely brought together different cryptic species and may even have interrupted local adaptation of a species, which has not changed since millions of years, is apparently not a fan of migrating, and which loves a stable habitat.

 

 

Yan et al wrote: "Since 2008, at least 72,000 Chinese giant salamanders have been released from farms. To what effect? Individuals recently caught from tributaries of the Pearl and Yangtze rivers were found to possess mitochondrial haplotypes of species B from the Yellow River, but no indigenous haplotypes [8]. By releasing huge numbers of farmed Chinese giant salamander, this genetically uninformed strategy may eradicate the evolutionary uniqueness of native allopatric populations and drive extinction by genetic homogenization [9]. "

 

Given that decline has happened faster than science could collect information on the ecological characteristics of the species, we may not even be able to understand what we have lost and what releasing farm animals will do the original species present in the different river systems. For sure, it will not be good.

 

One of the co-authors (Andrew Cunningham from the Zoological Society in London) puts it this way:  “Just one conservation breeding program is a huge ask, but to do one for each of the five species?” he says. “We’ve got to try but it’ll be extremely difficult. And even if we get down that route, I think hand on heart, we can’t say what the ecological needs of these lineages are unless we can find them in the wild.”

 

Its a tragedy!

 

 Photo: Giant Chinese Salamander. Ben Tapley.

 

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