• Dirk

A fisherman on a scientific mission in the mountains

Let's start right away with a quick introduction of the character: Antoine, PhD student in his last year at the Laboratoire Ecologie Fonctionnelle et Environnement of Toulouse. I am working on aquatic plants (which are not algae, I have to make the distinction!), but I am also a passionate amateur naturalist... and a sport fisherman in my spare time (if you can find free time while writing your PhD thesis that is).

But you will tell me... what did I go to do in the mountains, far from my Canal du Midi and my little protégés? For many reasons! Before elaborating, I would like to thank Dirk for having associated me with his team for this adventure; and I obviously thank my three wonderful travel partners: Adeline, Nikola and Pauline!

So let's draw up in this little post the reasons why I came... and the results of my two-day trip, spent in the Cirque de Lescun (64)!

The author in fishing action. A rod, polarized glasses to spot the fish, and you can get right into action!

To get out of the thesis and to train in other fields

This first reason is very personal! In the last year of my thesis, the experiments gave way to the analysis of the results and to writing, an extremely interesting period, but dense and especially almost exclusively spent in front of a screen. Getting away from the computer to "walk" in the magnificent office that are the Pyrenees, what better way to take a break and come back inspired to write? (I can see my PhD colleagues becoming envious when reading these lines).

And behind this purely personal aspect of optimizing the work of the thesis, it is also an opportunity to discover new scientific approaches. Here, it concerns the monitoring of mountain lakes and the collection of samples directly or indirectly related to the numerous amphibians that populate our Pyrenees. Fascinating animals and yet not very (re)known, I positively changed my opinion on them with each new outing in the mountains with the GloMEc and FishME team, looking for the furtive tadpoles or the Alytes hiding under the rocks (as if to better escape the innumerable threats - natural or anthropic - which mark their life).

Lake Lhurs

Serving as a "Sherpa

Let's not hide it, this is the real reason of my coming! Seasoned hiker, autonomy of 40 km per day, discussion companion (better than a donkey), the profile of the sport fisherman is being snatched up in all the labs of France and has nothing to envy to the impressive Tibetan Sherpas, who have allowed the beautiful days of world mountaineering! Well, let's stop joking here... none of this is true, I wouldn't allow myself to make such a boast! The mountain requires a good physical condition, but being part of Dirk's team is within almost everyone's reach. The main thing is to be able to form pairs and to share the equipment (too heavy and bulky to carry alone). And remember that each lake requires two hours of analysis... with two people! And yes, scientists in the mountains are not idle! So any good will in shape is welcome, I had the chance to be part of it!

To sum up, I would rather call myself a happy volunteer Sherpa (HVS, a new status to be developed for post-doctorate projects perhaps?).

Fishing of course! But by combining the useful with the pleasant...

Past the technical details - it's fine for thirty seconds, I agree with you on that - let's get back to the heart of the matter and moreover to the most important part: fishing! (laughs)

By now you may have understood: it is my passion! Since I was a child, I've been going around lakes and rivers in search of perch, pike and other trout. The techniques evolve and are very diversified nowadays. But the queen technique for scientific fishing in the mountains (Dirk, you will note my initiative on the name of this new approach), is fly fishing! With just a rod, a line (a kind of thick thread that allows to whip the line and to propel light imitations very far), a discreet leader and a fly (this is an imitation with hairs and feathers assembled on a hook so as to imitate any larva or adult insect), you can catch all kinds of fish!

My mission during these two days (in addition to the role of HVS) was thus to complete the information on the lakes. The fishing federations give indications on the fish present, but it is difficult to be sure of all the species present, and to have an idea of their size, or their level of pollution. So you have to fish for them! Techniques exist, and are used in the plain (net or electric fishing). But they are subject to authorization, and are very greedy in material. Impossible to set up such a protocol in the remote and sensitive environments that are our mountain lakes (except you use a helicopter, which is all but environmentally friendly). There is still the technique of the scientist's landing net... but between the time factor and the luck factor... I think it was high time to start fishing, the real thing!

Result : in thirty minutes on each lake, some major conclusions could already be drawn : presence/absence of minnow and/or brown trout ; estimation of the size and density of the individuals, level of catchability (= an idea of the fishing pressure on the lake). And above all, the possibility to collect the fish caught! One trout in a lake is enough to measure the quantities of pollutants present in its tissues, when about twenty minnows are needed. No matter, with a fly, everything is possible, as long as the fish is a little cooperative! This is where a good fishing experience helps, but with the right imitation model at the end of the line and a little discretion, catches can be made in a reasonable mount of time.

minnows captured in the lake of Lhurs (64). The fish are immediately killed to avoid any suffering, and frozen to preserve the integrity of the tissues before analysis in the laboratory. @A.Firmin

Lab analysis of the stomach contents of the fish will even determine what they ate at this time of year, giving even more information about the biodiversity of the study lakes. I am very proud that these few fish caught can eventually yield so much information! And all this without electricity, pollution or maggots used! Who said that scientific research could not be virtuous and eco-responsible?

Last point... a good fly fisherman also knows how to spot and identify larvae and insects on the water, it's useful to complete the lists of animals present! In short... it was the holy grail for an angler! Just imagine: to be chosen to fish freely during a scientific adventure, and that the fishes are used for science afterwards... what a dream!

The author in action. The bag filled with the analysis material, the landing net and the sticks, and the specific "fishing" chest-pack on the front. In the mountains, we go out equipped... and in any weather!

Fortunately, the shoes allow you to find your way in the fog! @P.Benzi

Working with a great team

I will conclude with this, of course! What would be an outing in the mountains without the exchange and the conviviality that are the keywords? Traveling for miles and sharing many anecdotes that only the mountain can bring out, having a quick picnic between two analyses, under a flight of vultures and kept awake by the cry of marmots... what could be more beautiful for a working day? And if you have the chance like me to be surrounded by three incredible colleagues, all mines of knowledge, skills, ambassadors of the mountain and seasoned hikers ... you will have a wonderful experience. Thank you all three, really!

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