Author: Adrian Colino Barea

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On how to teach a man to fish: experiences of my journey as a HiLIFE trainee

As a new year starts and new students are getting the opportunity to become HiLIFE trainees, I have been reflecting about what I did, learned and achieved during my own experience through this program.

I am Adrián Colino Barea, a (now) second year Master’s student of Ecology and Evolutionary Biology.  On March 2023, I was lucky enough to join the Integrative Evolutionary Biology (IntEvoBio) lab to answer what I first thought could be a trivial question that popped in my mind. Claudius Kratochwil, the PI of the group, helped me to plan a small project aiming to determine how light depletion determines sexual choice and preference in colorful cichlid fishes from the African Great Lakes. You can learn more about it reading my previous post, by clicking here.

Males of the fish I use for my experiment show yellow egg-shaped dots in their anal fin. Females lay eggs on the ground and brood them in their mouth cavities. When the ladies lay, the lads display their egg spots close to the ground. Females, confused, try to swallow the egg spots as they do with their eggs. Then, males release sperm and fecundation takes place. Evolution is amazing.

In a nutshell, and if you are wondering, my short internship project didn’t come up with significant differences of mate preference under light and dark conditions. I did not find out how colorful fish fall in love in the dark. Instead, I found out how usual — and important — it is to not have results in science. It is crucial to get a glimpse on what questions are relevant to answer, and what research lines are worth following and investing on. There is just so much to find out, trial-and-error is necessary to keep going.

I learned new limits of the beauty of commitment. For my experiments, controlling fish schedules involved feeding them, and I decided to take care of it. I found myself showing up in the fish room every single day, sometimes in breaks between classes, sometimes during lazy Sundays, sometimes under absolutely crazy weather… And I loved it. Working March to June, I got to experience the Finnish weather every day at least for a bit. It was not too special at the moment, and anyone could do it if living in Helsinki. But now I am really glad I got to see how the seasons change. Very often, I stopped by the fish room only to go walking in the forest or birdwatching later, and experiencing nature changing with the seasons before my very eyes. Days became longer, snow melt, flowers sprung, everything sprung. And this experience is just so different to what I grew into, coming from the other side of the continent.

Dramatic winter panorama after a blizzard at the end of March in Viikki Campus, back from visiting the fish room.

I also found myself becoming part of a community, formed by all the members of IntEvoBio lab. Over my working weeks, it was easy to be motivated to plan and act thanks to the great support and hospitality of all the members of the lab. I always felt encouraged to keep up and be up to date on meetings, presentations, and the deadlines I kept setting myself to meet ends — something vital in such a small project. Indeed, perfecting the art of managing time has been one of the most valuable assets I got out of the internship. But in this case, considering the inspiring time planning the whole lab follows, being organized myself was a piece of cake.

Another thing I learned and cherish is the value of kindness and humanity. During my internship, I always found a smile and willingness to help of the members of the lab I treated with, including people of all levels, from PI to Master’s students. Without this help, my project wouldn’t have developed after the very first stage. I received life-changing lessons on how to build my research career without falling into mistakes others fell into in the past. I learned how important it is to build and take care of relationships, as we got to welcome incoming researchers from distant countries and prepared the departure of some of IntEvoBio staff to other universities abroad. This is the spirit of the science of today: learning by sharing.

Although almost no one in the lab was a Finn during my stay, the spirit of properly balancing work and life was a rule throughout my internship, and I feel this is also part of the kindness and humanity I experienced. I felt welcome not only by having a cozy desk with plenty of lovely pictures and catchy fish jokes hung on the wall. I also loved lab outings. To wrap up the work of months, give farewell to a visiting researcher and say hello to summer, we went all together kayaking the Vanhankaupunginlahti in a hot day of June, right before the end of my internship, and then stayed for dinner. We really had a blast. And although few of this has to do with how fishes mate in the dark, it proved vital for the development of this project which tried to answer that question.

Laughs and fun on a lab outing, kayaking around Kulosaari on a warm, sunny day of June, with IntEvoBio lab. A great memory of a great experience overall.

As the proverb says, ‘Give a man a fish and you’ll feed him for a day; teach a man to fish and you’ll feed him for a lifetime’. Thanks IntEvoBio and thanks HiLIFE for helping me so much on my journey to learn how to fish.

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On how colorful fish fall in love in the dark

Have you ever stared closely at fish in an aquarium? Isn’t it just amazing to look at the plethora of shapes, colors, and different behaviors that the fish, living on the other side of the glass, display? My younger self really enjoyed the wonders of the aquarium hobby – I believe the underwater world bears some of the world’s most amazing representations of life, and those tanks could, in some way (ethical issues aside), depict a little part of these marvels. But, how do fish see each other? Are they attracted to the colors other fish display? If so, what happens then, in the dark?

I am Adrián Colino Barea, a Spanish wildlife biologist, and a current first year student of the Master’s Programme in Ecology and Evolutionary Biology at the University of Helsinki. My main motivation to join this programme here was to dig deeper in applied ecology in tropical regions, as the University of Helsinki has several research lines in the tropics. I am aiming to focus on biodiversity conservation: I want to contribute and make a difference to revert the trends that current human-driven impacts have on nature globally.

Not surprisingly, me in the outdoors, hiking, looking for some interesting endemics in Azores. Greatly attracted by field ecology, I would not have pictured myself doing this exciting lab-based internship back when this photo was taken!

While my passion has always been working on the field, touring the fish room of the Integrative Evolutionary Biology (IntEvoBio) lab during an introductory course of the master’s last year awakened my younger self thrill. Racks with tens of tanks full of cichlid fish from the African Great Lakes fill the room, all around us, while some of the IntEvoBio lab members, led by Prof. Claudius Kratochwil, guided us through the nuts and bolts of their interesting job with all these fish, and why they are so particularly wonderful.

African cichlids: the book example of speciation

The African Great Lakes are three massive freshwater bodies in tropical West Africa, originated by ancient tectonic shifts. However, these lakes have borne livable conditions for a relatively short time. A certain group of cichlid fish got to these waters and started evolving at an unprecedented rate, fitting every possible niche, and generating entire, complex ecosystems, all based in different cichlids. What is more, they display very different color patterns of colors, bands, and spots, and perform elaborated mating rituals. Their unusually fast evolutionary process is based in ‘sexual selection’, meaning that individuals choose others as partners based on certain traits of their preference, despite the fact that these traits could make them, for instance, more showy – and therefore easier to spot by predators, hence against ‘natural selection’ as described by Charles Darwin.

To put it in perspective, for any evolutionary biologist, the cichlids of the African Great Lakes are old acquaintances, and for some they are the entire reason for their research. For many biologists, they are just inexplicably special. Some even say that the basis of evolution today would be radically different, had Darwin visited these lakes instead of the Galápagos Islands almost 200 years ago, and looked to these fish.

While in the lab, I enjoyed seeing all of the complexity that I have read about, right before my eyes. The researchers explained to us how these fish (and their evolutionary process) strongly rely on color communication. They have developed color signaling to inform about their sexual status, the hierarchy within a group, and even some species can change their colors rapidly, to give fast information! 

Cichlids have evolved into a big variety of colors, shapes, and behaviors among the waters of the three African Great Lakes. Just to clarify, the big guy on top left is not a cichlid 😉

However, one of the drawbacks to this very fast evolutionary process is that it is also very fragile, as species may seem radically different in colors and shapes but have very similar DNA, because of how recently they have evolved. In addition to this potentially fragile evolution, these lakes are particularly vulnerable to the impacts of human development. Lake Victoria is the second-largest lake on the planet by area and a huge population increase, has led to 40 million people now inhabiting the coastal region This human activity has resulted in major issues related to biodiversity, mostly through pollution, overfishing, and introduction of invasive predator fish and floating plants. 

How does sexual selection work under deterred underwater light conditions?

In particular, an invasive floating plant, the water hyacinth (Pontederia crassipes), is causing terrible damage to all ecosystems in Lake Victoria, and migh spread to other lakes. These plants prevent light from penetrating, hindering the oxygen production in the water and making the ecosystems within it collapse. Moreover, the human communities around the lake cannot physically access their resources because of how dense and inexpugnable the floating mats are.

But, coming back to my initial concern, floating plants – as well as increases in turbidity – make the underwater dark. Is there anything happening directly to the cichlids? If they rely so strongly on visual communication for their daily lives and long-term evolutionary process, how do they cope under a scenario in which their vision – light supply – is hindered? How can they find and recognize each other effectively and ‘sexually’ select their preferred partners according to visual signals (colors)?

During my internship, beyond my research project, I am learning the basics of tank care and manipulating fish. I certainly work with beautiful animals, such as this Pseudotropheus (Chindongo) demasoni, and the yellow females of Ps. (Ch.) saulosi in the bucket.

Back during my lab visit, I asked some researchers and they didn’t have an answer. This visit was inspiring enough to raise meaningful biological questions, with profound biodiversity conservation meanings. I am very pleased that HiLIFE gave me the chance to shed light on this topic, by granting me a Research Trainee Scholarship. Since March, I can call Prof. Claudius Kratochwil my supervisor, and some of the PhD students that once showed me through their research, my helpful mentors. 

From March to today: the beginning of my experimental phase

During these months, I have been setting up my experimental arena, and dedicatedly come up with a protocol to follow. I am working on the mate choice of cichlid males over females under different light conditions. Only last week I started the experimental phase, and I am excited to know what will happen with the results that I am obtaining – I will keep you posted on my progress. If this experiment arise meaningful outcomes, these invasive floating plants would potentially be given a new threat to nature, and hopefully a new reason to focus efforts and find an effective solution in the field, for the cichlids, for the people in the region, and for the entire ecosystems.