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Officials in Washington State get worried about Xenopus invasion

01 May 2022

Invasive population of African clawed frogs in Washington State 

We have known about the invasion of African clawed frogs in Washington State for some years, but a new online article  hints at some of the potential impacts that these invasions might have.

Individual African clawed frogs have been sighted at at least three sites in Issaquah, Lacey and Bothell. One of these sites has a full blown invasion that officials from US Fish & Wildlife have been attempting to exterminate for three years. But due to a mixture of inadequate funds and COVID, the efforts to date have been unsuccessful. 

Interestingly, many of these introductions appear to have occurred after a change in law that made it illegal to have these frogs as pets. The result was that owners appear to have released their pets into the local environment and when sufficient numbers were released, an invasion resulted. This teaches us an important lesson in how to communicate to the public about invasive species and the law.

I have no doubt that we'll see more about this population in years to come.

  Frogs  Lab  Xenopus

Visiting a newly established population in France

01 May 2022

Visiting a new invasion of Xenopus laevis near Lille

Over the years I have managed to visit quite a few of the invasive populations of African clawed frogs covering all 4 continents on which they are currently known (Measey et al 2012). When reviewing these invasions, we found that the pathways were mostly due to the release of animals from scientific laboratories, but in 2017 when I reviewed the sources of current trade in these same frogs (Measey 2017), I predicted that we would start to see an increase in populations introduced from the burgeoning pet trade. 

In September 2018, it was reported that a population of African clawed frogs was present in a pond of the small French town La Chapelle-d'Armentières, near Lille and close to the border with Belgium (van Doorn et al., 2022). Although we do not know much about the pathway of this introduction, it appears that the pond in question was renovated by the council around the same time as the discovery, making the pond both deeper and thereby permanent (using images from Google Earth). A swift survey of numerous water bodies on the Belgian side of the border suggested that this pond is currently the only location for this established population (van Doorn et al., 2022). 

As I was in northern France in late April 2022, I requested permission to trap at the pond and process samples for our ongoing work into native and invasive genetic diversity of this model species (see blog posts here and here). The pond had been partially drained and a sturdy drift fence was planted all around the perimeter in aid of the eradication of this species from the area (seeTechnical Reportfor more information).

I set 4 traps in the two remaining areas and the next morning found 21Xenopus laevis

Further Reading:

van Doorn, L., Speybroeck, J., Adriaens, T. & Brys, R. (2022). Environmental DNA sampling for African clawed frog in Flanders, Wallonia and France in 2020. Reports of the Research Institute for Nature and Forest 2022 (6). Research Institute for Nature and Forest , Brussels.

Technical Report on removal of Xenopus laevis

  Frogs  Lab  Xenopus

An interview on 'How to write a PhD'

15 April 2022

Interview with Daniel Shea from Scholarly Communication

Daniel contacted me some time back about doing an interview for his podcast on Scholarly Communication. I had a listen to excerpts of some of his previous interviews and wrote back with enthusiasm. I had a copy of How to Write a PhD in Biological Sciences  delivered to Daniel and we set a date for the interview. I had spent some time working on the next book (How to Publish in Biological Sciences) and so did a quick recap of the contents of How to Write a PhD in Biological Sciences  in the morning before the interview. Nevertheless, I was not feeling particularly well prepared when we started talking. Daniel explained that he would give a prepared introduction, and after this would launch into the interview.

It was quite a shock when Daniel gave a very lengthy introduction including reading a quote from the book. What struck me most was that he had actually read the book - apparently from cover to cover (not something that I'd advise for anyone wanting to use it!). His insights were eye opening. He had picked up on exactly why I wrote the book and that it is likely to be of use to people beyond only those writing PhDs in Biological Sciences. Moreover, Daniel had me thinking very hard on my feet about exactly why it is that we have built up a system with so much assumed knowledge. 

I should qualify the statement on assumed knowledge by adding that this may not be the case for all students (PhD, MSc or others). There are certainly some students who are well informed, and have all the knowledge on the system that they are working within prior to starting their PhDs. It's hard to know exactly where this came from and whether it was in the form of curricula based activities or that they had benefited from exceptionally good contacts. Evidently, the book is not needed by all students, but my experience, both as an uninitiated student and as an advisor, suggests that a great many would gain some benefit from the contents.

I was also very happy that Daniel was enthusiastic for the Bookdown approach. I may not have given a particularly useful explanation of what Bookdown is or why it's so great, but I would encourage you to go look at a product:

To listen to Daniel Shea's interview with me, visit:

  Lab  Writing

A checklist for Angolan herps

01 April 2022

A trip to Angola 13 years ago...

It seems like a long time ago when in January 2009 we set off up the N7 through Namibia to Angola to join a SANBI expedition to the southern highlands of Angola and Iona National Park. Our team on reptiles and amphibians consisted of Krystal Tolley and myself (then from SANBI) and Bill Branch and Werner Conradie (from BayWorld). We were just one component of many teams from different disciplines that joined forces to inventory the biodiversity of southern Angola.

As time has gone by, there have been many more trips to Angola with many more people involved. Together, all of this data represents an important resource, and has now been written up as an updated herpetofaunal inventory for Iona National Park by Javier Lobón-Rovira and colleagues, and published in the journal Check List.

With 5 amphibians (the park is essentially a desert) and 70 reptile species, the new check list records 40 of these for the first time in Iona National Park. This is a remarkable achievement.

Read the full paper Open Access here.

Lobón-Rovira J, Vaz Pinto P, S. Becker F, Tolley KA, Measey J, Bennet B, Boon B, de Sá S, Conradie W (2022) An updated herpetofaunal species inventory of Iona National Park in southwestern Angola. Check List 18(2): 289-321.

  Frogs  Lab

Retrieving loggers from KZN

14 March 2022

Downloading data from Hobo loggers

Sometimes you have to take a leap of faith and leave expensive equipment in the field in order to get much needed long-term data. This is what we did last February in a trip to KZN where we made an elevational transect while collecting African clawed frogs for Laurie (see Blog Post here). We placed four loggers at sea level, 1000 m, 2000 m and 3000 m asl. Sadly, the logger at 3000 m asl disappeared very soon after we placed it in a deluge of floods that hit Lesotho in March 2021. That meant that there were still three more loggers out in the field that needed to be retrieved. 

Fortunately, with the help of Bongani Ntloko from Letseng mine, we were able to redeploy another Hobo logger into a pond with Xenopus at ~3300 m asl. The results after one year (March to March 2022-23) are amazing.

Firstly, note that the scale on the y-axis only goes up to 20 C, and the water never gets that warm. For most of the year, the water is below 10 C. Only from around mid-October to late-March is the water above 10 C. This means that the frogs in Lesotho are more than half of their year in water less than 10 C. Even in summer, the water still regularly dips below 10 C on a daily basis.

Happily, the logger from 2000 m asl at the Fat Mulberry was retrieved by Marggie and she brought it to Stellenbosch where we could download the data.

This month I made a trip back to KZN to retrieve the outstanding loggers from near Dalton and at Bonamanzi:

The temperature of the water in a dam near Dalton never went below freezing, but it did get quite cold (as well as getting hot in the summer). 

Meanwhile at Bonamanzi, the temperature was nearly always above 10 C, and even went above 40 C! Contrast this with Lesotho when the water temperature rarely went above 10 C!

You may remember that Bonamanzi was where we had our traps vandalised by crocodiles. Happily though, you can see that the logger (right) didn't come to the same fate. The logger near Dalton (left) was still tied to the same stone sunk in the dam. 

Thanks to friends in Lesotho, we redeployed one of these Hobo devices there. Because you can replace their batteries, they are fantastic and just carry on working. We are hoping that the new logger won't go AWOL!

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