The history of TZS dates back to the 1880s, when Johan Axel Palmén, a newly appointed professor of Zoology at the University of Helsinki, was eagerly planning his teaching. He soon faced great difficulties in getting fresh or even decently preserved material for his anatomy courses. How much easier and more interesting would it be, if students could learn about animal species and their natural history in the outdoors instead of being confined to museum collections and libraries, Palmén reasoned. What a pity and shame that by far the best season to learn zoology was spent by students back home in idleness! Would it be possible to get this unproductive tradition changed?
Professor Palmén was a man of action, ready to try anything he believed in. He was one of the first in Finland to understand the importance of Darwin’s new theory on evolution by natural selection. He was determined to introduce new ways of teaching and learning zoology and was ready to invest his own money to achieve his aim. As a first step, he hired two fishing cottages on the island Esbo-Lövö in 1889. They served as a modest Zoological Summer Laboratory, as he later on called this endeavour. Two of his assistants initiated the research activities at this new base, while the professor himself visited only occasionally. Later on Esbo-Lövö formed a small universitas, in the original sense of the word, where older and more advanced zoologists taught younger ones.
Brackish water fauna was very poorly known at that time, and soon became the main focus of the studies on Esbo-Lövö. The value of the abundantly occurring rock-pools with their almost endless variety of environmental conditions was also soon recognised. Within a few years, intense studies of these "natural aquaria" were going on.
Palmén soon recognised the advantages his Summer Laboratory offered for both teaching and research and consequently decided to change his provisional base to a permanent field Station. Since it was impossible to purchase Esbo-Lövö, he abandoned it in 1899 and began to search for a new place. After having visited a few unattractive sites, he came to Tvärminne, the south-eastern corner of Hanko peninsula, in the autumn of 1901, to examine the suitability of a fisherman’s estate, which was for sale. Palmén was pleased with what he saw and immediately purchased the estate. The site of the new field Station was fixed!
Activities at TZS began in spring 1902. While Palmén himself was busy getting his Station started and planning all necessary repairs and rearrangements of the old buildings, three young scientists, one of whom was a foreigner, were eagerly engaged in their studies: fish parasites, local flora and turbellarians. Thus, two principles that have remained characteristics of Tvärminne were determined right from the very beginning: to welcome foreigners and not to be limited to zoology although Palmén, as a Professor of Zoology, called it a Zoological Station.
During the next few years, some new houses, such as a two-storey laboratory building, were built. The area of the property was increased by further purchases and a motor boat was bought to facilitate the connections to the railway station and also for moving around in the surrounding archipelago. Palmén financed all this with his own money. He owned the Station and ran it as his private endeavour. What an extraordinary man he was!
The number of scientists and students increased steadily. By 1909 it had become evident that the original teaching system was too tedious and time consuming for the teachers, and the very first official course was organised.
The only fundamental change followed Palmén’s death in 1919. Under the provisions of his will the Station was passed on to the University of Helsinki, and is nowadays part of the Faculty of Biological and Environmental Sciences. World War II brought about an interruption to the activities at the Station, which lasted from the evacuation of the Station in March 1940 to the summer of 1945. After the Winter War, the Soviet Union "rented" the Southern Cape Hankoniemi and surrounding islands for a military base for 50 years, but was forced to leave Hanko in December 1941. By the end of the decade the Station was again operating and fully engaged in teaching and research within the limits set by rather poor resources.
Throughout the 1960s, the summer activities exceeded the capacity of the Station. Two small wooden barracks were erected to ease the problem, but it was evident that the problem demanded more radical solutions. A series of new buildings was planned and towards the end of the decade, the University decided to start the building project, including four new brick buildings with a total floor area of more than 6,000 m2. The new buildings were taken into use in spring 1970. The number of staff was also increased in order to meet the demands and take advantage of the possibilities the new facilities offered. The most apparent change was that the Station was now functioning on a year-round basis. This new era was characterised by a considerable increase both in research and in educational activities.
Ironically enough, immediately after it had been established the existence of the Station was endangered by plans to build a huge oil refinery just a few kilometres away! However, in 1972 after a colourful "media war", the Finnish Government decided not to build the refinery because of its harmful effects on Tvärminne Zoological Station. In those days, the Station started to carefully monitor land use and environmental affairs on Cape Hankoniemi and the surrounding area.
During the decades that have passed since the planning of the four new buildings, marine science has developed into a more laboratory orientated science and the importance of experimental studies has steadily increased. Accordingly, our laboratory building became outdated and could not meet the requirements of modern science. In order to up-date the available facilities at the Station a thorough reorganisation and reconstruction of the building was carried out in 1997-98. In addition, two smaller laboratories for summer time experimental studies were built. In autumn 2021, the next upgrade was initiated, with the renewal of e.g. the aquarium facilities and climate rooms in the main building.