Ongoing research

Seasonal and spatial variation of herring quality characteristics in the Archipelago Sea

The project studies seasonal and spatial variation of herring quality characteristics (e.g. muscle fat content and quality) in the Archipelago Sea. The aim of the project is to produce useful information for both consumers and fish industry.

The project is funded by the Archipelago Sea Fisheries Action Group (Saaristomeren kalatalouden toimintaryhmä) (PI Jari Hänninen).

The variability and significance of iodine and thyroid hormones on the Baltic Sea organisms and ecosystem functioning (Iodine project)

The project studies the long-term, seasonal and spatial variation and effect of iodine and thyroid hormones in the Baltic Sea ecosystem and key organisms such as the Baltic herring, bladderwrack (Fucus vesiculosus) and zooplankton. A major aim of the project is also to test and develop methods to measure the concentration of iodine and thyroid hormones in the local environment and species.

The project is conducted in close collaboration with the departments of Biology (Ruuskanen Group and Anttila Lab) and Geography and Geology of the University of Turku.

The project is funded by Sakari Alhopuro Foundation (PI Katja Mäkinen).

Trap net project

Photo: Johannes Sahlsten

The herring data set has been largely collected in close collaboration with local fishermen, from who we have annually received samples of spawning herring. However, in the recent years, traditional method of fishing spawning herring has largely been abandoned and the trap net catch of herring has decreased as a consequence of this.

The aim of the two-year project (2019-2020) is to continue to collect spawning herring samples from the Archipelago Sea as well as to transfer knowledge and skills from professional fishermen to students. The project is conducted in collaboration with local fishermen and Livia college.

The project is funded by the Southwestern Finland ELY-centre and European Maritime and Fisheries Fund (EMFF), Archipelago Sea Fisheries Action Group (Saaristomeren kalatalouden toimintaryhmä).

The prevalence of Corynosoma-worms in the Baltic herring and Great Cormorants at the northern Baltic Archipelago Sea

The project aims to study the distribution and occurrence of Corynosoma worms in Baltic herring and Great cormorant populations in the northern Baltic Sea.

Corynosoma worms on a petri dish. Photo: Johannes Sahlsten

The project is funded by the European Maritime and Fisheries Fund (EMFF), Archipelago Sea Fisheries Action Group (Saaristomeren kalatalouden toimintaryhmä), and Southwest Finland ELY-centre. The research is carried out together with the Joensuu Molecular Ecology Group of the University of Eastern Finland.

More information:

Related theses and reports:

  • Johannes Sahlsten & Jari Hänninen (2020) “Silakan loismatojen esiintyminen, isäntälajit ja vaikutus Saaristomeren elinkeinokalatalouteen” Hankkeen loppuraportti. Study report (in Finnish) (Pdf).
  • Sahlsten, Johannes. 2019. Corynosoma-suvun väkäkärsämatojen esiintyminen Saaristomeren ja Selkämeren silakoissa. University of Turku, Turku. Bachelor’s thesis.

The future of the Baltic Sea and us: the effects of climate change to the Baltic Sea pelagic ecosystem

The purpose of the project is to provide information on the key changes that can be expected in the Baltic Sea pelagic ecosystem if the current sea stagnation continues and/or climate change is progressing to increased precipitation in the Baltic watershed area. Besides ecological changes we deepen the analysis to include occurring biochemical changes in the ecosystem, especially in the phytoplankton – zooplankton – herring food chain. The food chain analysis will define whether the herring’s nutritional value for human consumption (e.g., fat types) has changed resulting from the Bothnian Sea zooplankton community change making it less favorable diet for herring.

Limnocalanus macrurus, C: Marjut Rajasilta

 

The study is conducted in cooperation with Food Chemistry and Food Development, University of Turku. The research is supported by the Finnish Cultural Foundation, Jenny and Antti Wihuri Foundation and Turku University Foundation.

Related publications and theses:

  • Mäkinen, Katja. 2019. Climate-induced Variability in Northern Baltic Sea Zooplankton – Assessing Driving Forces and Effects on Higher Trophic Levels. Annales Universitatis Turkuensis Ser 358. University of Turku, Turku. PhD dissertation. Pdf.
  • Mäkinen K, Vuorinen I, Hänninen J (2017). Climate-induced hydrography change favors small-bodied zooplankton in a coastal ecosystem. Hydrobiologia. 792:83–96.
  • Mäkinen, K., Elfving, M., Hänninen, J., Laaksonen, L., Rajasilta, M., Vuorinen, I., & Suomela, J. P. (2017). Fatty acid composition and lipid content in the copepod Limnocalanus macrurus during summer in the southern Bothnian Sea. Helgoland Marine Research71(1), 11.
  • Rajasilta, M., Hänninen, J., Laaksonen, L., Laine, P., Suomela, J. P., Vuorinen, I., & Mäkinen, K. (2018). Influence of environmental conditions, population density, and prey type on the lipid content in Baltic herring (Clupea harengus membras) from the northern Baltic Sea. Canadian Journal of Fisheries and Aquatic Sciences, (999), 1-10.
  • Laaksonen, L. (2014) Itämeren makeutumisen vaikutus silakan ja silakan ravinnon rasvahappokoostumukseen. Opinnäytetyö (AMK). Bio- ja elintarviketekniikka. Biotekniikka.