First boating trip on the Bodensee

The past summer, I successfully completed a motorboat course to enable me to drive a motorboat on the Bodensee, required for my ongoing research on fish collective behaviour. I got my “Sportbootführershein” in the post a couple weeks ago, and finally this weekend was able to ‘take the boat out’.

driving-the-motor-boat

In the cold rainy weather of early November, I set-off with with a good friend on one of the motorboots from the Limnological Institute. The water was considerably clearer than during the summer, providing a visibility of just over 5 meters. It was beautiful being out on the water. However, in the first hour almost being out, we still hadn’t seen our first fish!

view-over-the-lake

We navigated around the island of Mainau, and started exploring the very shallow areas near the mainland. I was a bit annoyed I hadn’t seen any fish yet, let alone any sticklebacks, but when we decided to cross under the bridge leading to Mainau we suddenly found thousands of them!

The water was so shallow that it was necessary to take the motor out, and continue by oars. But this also meant we could observe the swarming fish from very close. Despite sticklebacks being very abundant in the Bodensee, in the autumn and early winter most of them move to deeper waters, likely following the movements of their invertebrate prey. These remaining fish were apparently some of the last ones remaining in the shallows, likely seeking shelter in the shadow of bridge, and I was therefore very happy to have found them.

We spent about half an hour observing their movements and behaviour and I got some good ideas to come back for some more quantitative field measures of their group sizes and compositions. After that we decided to go for a quick snorkel before going back to the harbour.

with-wetsuit-on-the-boat

With my freediving wetsuit, the 11 degrees C actually still felt very comfortable, and I was enjoying the relatively clear waters of the lake. The Bodensee has a very interesting geology, with relatively shallow water on its edges that can suddenly drop almost vertically tens and tens of meters into the deep.

We only snorkeled a bit above a drop-off near the harbour to check our wetsuits and the visisbility, which both passed our expectations. I therefore can’t wait to go back again and take the boat out the lake to catch wild individuals for my experiments, get some more quantitative observations of the sticklebacks and their predators, and explore underwater.

Submitted von Humboldt Fellowship

alexander-thumbToday I submitted a grant application for an Alexander von Humboldt Fellowship, entitled The ecological and evolutionary implications of individual differences in collective behaviour. The goal of the proposed project is to develop an interdisciplinary research program to investigate the link between consistent behavioural variation, the emergence of collective properties, group functioning, and ultimately individual fitness and between-group dynamics. I am very excited about this project and have started to lay the foundations for it here in Konstanz. Now 10 months wait ahead!

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Wild schools of Moderlieschen

Last weekend I went exploring the streams and lakes in the countryside near Konstanz to search for Moderlischen and determine the possibilities for doing fieldwork to investigate group movement dynamics and composition in the wild.

I was able to find them in some tiny streams leading to a small lake, showcasing some nice examples of collective shelter use and leadership and exploration of the stream, see the video below. Looking forward to starting exploring possibilities to start some actual field work on these populations.

New stickleback in the lab

For my new research projects on the role of individuality in collective movements and decision making at the University of Konstanz, I have been getting new sticklebacks from the Bodensee. Last weekend I went to see them together with my 10mo son! I think it was the first time he actually ever saw moving fish. Although I showed him fish in aquaria before, he was too young to react to them, but this time he was amazed by the large school of fish swimming back and forth. The sticklebacks from the lake were absolutely huge, I estimate up to about 9cm, much bigger than the ones I ever saw in Cambridge and the ones in the ponds near the University here. I hope to go on a trip soon to observe the collective behaviour of the sticklebacks in lake Konstanz, the ponds, and streams in the area to set-up some exciting experiments on the population-specific differences of this amazing species.

Here I am showing my son a school of Moderlieschen

Here showing my excited son a school of Moderlieschen

Short visual on vectorized movements of small fish school

My research is currently centred around understanding the role of consistent behavioural differences in the collective movements and functioning of animal groups. In particular, I assay large numbers of stickleback fish on various personality traits and expose them in groups to different ecological scenario’s. I have written custom tracking software in Python using the OpenCV library to be able to accurately track the position of individual fish in the freely-moving schools.

Today I wanted to share a simple visual that highlights the detailed individual-based tracking of a small fish school over time. Each fish is represented by a different colour, with the arrow showing its vectorized movement, with larger arrows indicating a higher speed. The video is centred around the vector of the group as a whole to better visualize the structure of the group over time. Lines indicate the smallest polygon encompassing all individuals and Individual Centre Distances. The moving axes indicate the relative speed of the group in a large circular arena.

In this short section of a 30-min long experimental trial it is clear that the group speed, cohesion, and structure fluctuate over time. At the same time, individuals also maintain to some extent their positions relative to the group centre, such as the green and yellow individual clearly having a stronger pulling power on the movements of the group as a whole.

I used RaspberryPi computers to film the fish, custom Python tracking scripts to acquire individual X,Y coordinates for each individual in the group, R to process the tracking data and acquire movement characteristics, and R with ffmpeg to create the visual.

Drawing sticklebacks

I have been trying to improve my drawing skills to better illustrate how my sticklebacks behave and in what way personalities matter in collective behaviour. I still have a far way to go but this is my latest quick sketch that shows four sticklebacks with different morphologies. When I get more time on my hands after I hand in I will try to get some more elaborate drawings done!

stickleback-drawing

Almost there..

Just over three years ago I was standing up to my waist in cold water, somewhere in the vicinity of Cambridge. I was catching sticklebacks for the first experiments of my PhD. Now, 37 months later, I am in the final stages of writing-up and will actually hand in my thesis in ten days time! During this last chapter of my PhD, I have also become a dad and am actually writing this with my 5 month-old son in the carrier on my chest. Luckily, after a nice walk with our dog in the cold autumn air, he has fallen vast asleep.

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If it wasn’t for all funding falling away at the 3 year mark, one and a half month ago, I would be continuing with some additional exciting data chapters of which I already got the data. However, with five data chapters, two of which are published and two have been accepted, I have enough exciting work to talk about. In the months to come, I will be wrapping up a lot of small and large stickleback projects that I have done over the years and that have not made it into my thesis, besides some nice collaborative studies, and will continue with further experiments on the link between personality and collective behaviour as a Postdoc!

Now, time to get back to thesis writing..

Three-spine stickleback close-up photo

I have been taking quite a lot of photos and videos of the sticklebacks recently for public engagement and wanted to share this large close-up photo with you. Although it is a three-spine stickleback, it actually only has two spines, a feature that is common amongst this species.

Stickleback-closeup

Click the image to get the full-size photo! 

Stickleback spine-use project

Very recently two part IB students of mine finished a nice little experiment on the spine-use of three-spine sticklebacks. We were interested to see how personality might be related to the raising of the spines of three-spine sticklebacks as it helps them in protection against predators. Watch this close-up video that I took that nicely shows one individual stickleback raising its spines and lowering them again after feeling threatened by my presence. Hopefully soon we have the manuscript out with the findings of our study!

Last experimental work of PhD finished!

stickleback-testing-JollesToday I finished my last experiment that will be part of my PhD! I have been locked away in the lab for a couple weeks, testing hundreds of fish on their personality and collective behaviour, but now analysis and writing can fully start. I must have tested close to a thousand fish in the two and a half year since the start of my PhD, most of which are now enjoying a happy end of their lives back in the wild. I have all the data of a number of exciting projects that will not need me to go back to the lab for at least half a year but I can actually not wait to test my next hypothesis! The three-spine stickleback is an amazing species to work with and I will definitely continue working with them after my PhD.

New video of three-spine stickleback in my lab

Today I took a new video of the stickleback in my lab to use to talk about my work and these amazing fish during public lectures and conference presentations!

What you can see really well in this short little video is the large morphological and behavioural variation of the fish. Despite being similar in age the fish are quite different in body size as well as their colouration. Also pay attention to the spines, you can see individual fish often raising their spines at the moment they feel threatened by my presence.

One of the social housing tanks I use to house some of my hundreds of little stickebacks

One of the social housing tanks I use to house some of my hundreds of little stickebacks