In September 2014, I visited the University of Bergen in Norway to work with Professor Mikko Heino and colleagues with the Evolutionary Ecology (EvoFish) research group. The purpose of my visit was to 1) sharpen my understanding of fisheries-induced evolution in fish stocks; and 2) learn about a method to describe variation in maturation in wild fish – namely probabilistic maturation reaction norms for age and size at maturation. 

L-R: Christian Jørgensen, David Gislason and Mikko Heino. Mikko holds the one and only EvoFish trophy. Only students who finish with the group can get their name on it. It’s a great honor and while simply visiting the group is not enough, I was allowed to hold it.

The EvoFish group is at the core of fisheries-induced evolution research.  The members of the group have published several papers on the effect of selective harvesting on fish stocks, especially on possible evolutionary changes in important traits like age and size at maturation. My days in Bergen flew by as I tried to model both growth and graphs called “ogives” (cumulative histograms) for Lake Erie Yellow Perch, before I could start to estimate probabilistic maturation reaction norms with Mikko’s help.

The Department of Biology at the University of Bergen is in a newer building located in a beautiful setting on the harbour. Just steps away from the building it was possible to see schools of juvenile fish swimming in the harbour. The atmosphere in the department was very friendly, and I was given a key to the department and an office during my stay. Most faculty and some students gathered each day for lunch and everyone was willing to speak English so that I could take part in the conversation. Smoked fish, shrimp salad, pickled herring and local cheese were among my favourites for lunch.

Lunch with the Evolutionary Ecology group (EvoFish) in Bergen. Counter-clockwise from front left: Christian Jørgensen, Mikko Heino, Sigrunn Eliasen, Göran Högsted, Øyvind Fiksen, Anders F. Opdal, Adèle Mennerat, Snorre Andersen and Simon Miljeteig.

During my visit, I took part in a meeting with Mikko’s lab. With the help of a postdoctoral fellow, Dr. Beatriz Días Pauli, I learned about a fisheries experiment that Mikko’s group is undertaking to investigate the effects of harvesting on fish populations. The experiment is set up in a lab where the environment can be tightly controlled.The experiment involves three populations of Guppy (Poecilia reticulata) that are “fished” in different ways: 1) by selecting the biggest fish, 2) by selecting the smallest fish, and 3) by randomly selecting fish. This approach mimics fishing scenarios that could occur in commercially harvested fish populations and has great potential for advancing our understanding of the effect of different fishing selectivity patterns on fish population evolution. 

Postdoctoral fellow Dr. Beatriz Díaz Pauli inspects fish that are part of a fisheries experiment at the Department of Biology, University of Bergen.

I also had an opportunity to give a talk about my research at a departmental seminar series, which resulted in productive discussions with members of the department. Postdoctoral fellow Fabian Zimmerman walked me through his research on selectivity of gill nets and trawls, and how harvesting with both methods might minimize possible changes in age and size at maturation based on model that he is working on. On the final day of my visit, I met up with Mikko in downtown Bergen for a delicious fish cake lunch before we toured the Bergen Aquarium. In the evening, Mikko invited me to his home where we chatted about our respective work over a great fish dinner.  I left Norway very happy about my experience there and much wiser about probabilistic maturation reaction norms, their estimation and interpretation.

David Gislason with Dr. Hilmar Malmquist (left), Director of the Icelandic Museum of Natural History in Reykjavík.

My flight to Iceland from Norway was fabulous; we flew over Iceland in clear weather and I was able to see an active volcanic eruption in the highlands. During a stopover in Iceland, Dr. Hilmar Malmquist, director of the Icelandic Museum of Natural History, very kindly arranged a desk and internet access for me at the University of Iceland campus so that I could continue to work on my research and my newly acquired knowledge from Norway while visiting family, friends and colleagues in the country.

I wish to thank the Canadian Fisheries Research Network for providing Strategic Network Enhancement Initiative funds to support my trip to Norway.  I also thank Mikko Heino for his hospitality and help, everyone I met in the Department of Biology, University of Bergen, and finally Hilmar Malmquist for providing me with office space in Iceland.