Archipelago Research Institute

Field station full of stories

New research project investigates parasites found in the Baltic herring

In the Archipelago Research Institute, the reproductive biology of the Baltic herring (Clupea harengus membras) has been studied for over 30 years, since 1984. During the last few years we have discovered large amounts of parasitic worms in the body cavity of herring, collected from the Airisto Inlet. The phenomenon is new as no worms have been previously discovered in our samples. Dna-analyses conducted by the University of Eastern Finland showed that the parasitic worms are in fact two species (Corynosoma strumosum ja C. semerme), belonging to the phylum Acanthocephala. A new research project, studying the distribution and occurrence of these worms in the local herring, seal and great cormorant populations will begin next summer. 

Acanthocephala, also called thorny- or spiny headed worms, are commonly found in fish and seals. In Finland, 11 species are known to occur. The parasitic worms don’t infect humans. The Baltic herring is a safe and nutritious food fish and no cold treatment is required when preparing the fish.

herring_sample

According to our preliminary studies, in 2014-2015, approximately 15% of herring in the Airisto Inlet were infected by the parasitic worms.

Corynosoma-worms use herring as an intermediate host. The grey seal (Halichoerus grypus) and/or ringed seal  (Pusa hispida) are definitive hosts for the Corynosomaspecies. Of the two seal species, the grey seal is common in the Bothnian Sea and nowadays also in the Archipelago Sea. The steady increase of the grey seal population and its spread to the middle- and inner archipelago might have caused the parasitic infection in herring. The species C. strumosum has also been discovered in  Great Cormorants (Phalacrocorax carbo). Therefore, it is possible that the bird species is also a definitive host as the increase of the cormorant population coincides with the timing of our findings.

herring_sample

Parasitic worms may cause negative effects for commercial herring fishery. Therefore, it is important to understand the extent of the phenomenon and the causes behind it.

The two-year study is funded by the Archipelago Sea Fisheries Action Group (officially Saaristomeren kalatalouden toimintaryhmä in Finnish). The research is carried out together with the Joensuu Molecular Ecology Group of the University of Eastern Finland. The project’s field work begins next summer. The aim is to chart the distribution and occurrence of the parasitic worm species in the local herring population. We will also investigate whether the Great Cormorant is a definitive host in addition to the grey seal.

Stay tuned for updates from the field!

Planning the future of field courses

Last Wednesday morning, a few of us headed towards the University of Helsinki’s Lammi biological station, where we were to attend in the  BIOPEDA -project’s second seminar, funded by the Kone foundation. In the first 3-day seminar, organized in March in the Konnevesi research station (University of Jyväskylä), teachers from every Finnish university came together to discuss the current state and future of biological field courses. Outcomes of this seminar were a webpage maasto-opetus.fi and a publication, published in the Journal of University Pedagogy (in Finnish). The aim of this 2-day seminar was to further develop the webpage, aimed at benefiting both university teachers and students, and to plan future events. 

Field courses are a central part of biological and other nature-related studies. Despite of their relevance, field courses and, also, field stations have been under budget-cuts. The aim of the BIOPEDA project is to improve cooperation between teachers and sharing of teaching resources within the Finnish university research network. This will aid both to reduce costs and improve the diversity and quality of courses offered to students, thus increasing the expertise and know-how available in Finland.

lammin biologinen asema

The snowy landscape of the Lammi biological station.

lammin biologinen asema, biopeda seminaari

Between planning, we also had time to listen and watch a presentation about a Svalbard trip.

Read more:

Maasto-opetus.fi, the university fieldwork website provides fieldwork related resources to teachers and students.

Turpeen uumenissa -blog, news and stories about fieldwork

Finnish Research Stations – a network to reach different Finnish biotopes and ecosystems

We will take a small break from posting new content and  are unplugging to enjoy the holidays. We will be back with new content again in the beginning of next year! We wish everyone a merry Christmas and a happy new year!

Season's greetings from ARI

Q&A, What do we do in Seili in winter?

Some of the most frequently asked questions we get is “What is it like to work and live in Seili in wintertime?” “What do you do in Seili during winter?” and “How can I travel to Seili in winter?” The institute has operated in Seili year round since its beginning and our actions are generally governed by the busy summer field season and the more peaceful winter season.

Seili winter

When summer turns to autumn and winter and the ferry m/s Östern, operating between Nauvo, Seili and Hanka, ends its summer season, we turn our focus towards the upcoming winter. Even though the weather might still be sunny and warm, the approaching winter season is obvious as one by one the summer employees leave the island and visiting researchers end their field work and experiments for the year. What remains is the core group that takes care of the infrastructure.

As things slow down on the island, the University campus is starting the new academic year, which means that the number of university board meetings etc. increases exponentially. For this reason, a part of our staff move their office for the winter to the Turku university campus area (Matthias-building) and work in Seili only occasionally.

A great weekend getaway for photographers and astronomical enthusiasts. The city lights won’t bother you here, but instead, pack a  headlamp.

For those who work in Seili full-time year round, the wintertime is devoted for maintenance tasks. During winter, sampling equipment are inspected and, if needed, repaired and calibrated, and lab stores are refilled for the next summer. Our service men, Pete and Kari, also take the Institute’s vessels and boats out of water and make sure they are ready for the next season. This winter, there are also several renovations going on, something new is under construction..

The lights at the workshop don’t go out in winter. The peaceful wintertime is devoted to maintaining the infrastructure at Seili.

In autumn, some of the sampling programs, like the moth monitoring, end when the temperatures fall below 0 degrees. One of last big sampling efforts is the fishing of herring for The Finnish Radiation and Nuclear Safety Authority’s (STUK) monitoring purposes. The water quality monitoring, however, is continued year round, and every ca. 10 days the Institute’s preparator, together with Kari or Pete, travel to the sampling point, located north of Seili, to take water samples and measure the temperature and salinity of the water column. Every month, zooplankton samples are also collected. The wintertime sampling is mainly governed by ice and wind-conditions, but usually only during rasputitsa the monitoring cannot be continued as it is not either possible or safe to travel to the sampling point with a boat, snowmobile or hydrocopter.

Seili winter sampling

Sampling in winter 2006. Exceptionally, the trip from Seili post jetty to the sampling location was done with a hover craft.

It is easy to travel to Seili even in the wintertime. After the summer season, a public ferry, m/s Falkö operates between Nauvo and Seili. The biggest differences is in the timetables, in winter, it is possible to travel to Seili and back only on Tuesday, Wednesday and Friday. The ferry ride also needs to be booked at latest the day before. This winter, the Nauvo guest harbour is also under construction and thus, the ferry operates from Keso shipyard in Ernholm, Nauvo.

Interested in traveling to Seili in winter, but the ferry timetables don’t fit your schedule? We offer transportation services year round. More information and price list here.

Surveying meadows in Seili

Meadows are traditional biotopes in Finland and during this summer we took a closer look at meadow plants in Seili. Proper equipment and careful planning are the basis of sampling plants. It’s wise to keep close to you at least a good plant identification guide and a sampling square (quadrat). Sometimes a magnifying glass is also necessary to check some small details.

Cover and density estimates are important parameters of changes in vegetation. This inventory also gave an opportunity to pause and admire the beauty of the plants, butterflies and other insects.

A quadrat is a plot used in ecology to isolate a standard unit of area for study of the distribution of an item over a large area

Common Moonwort (Botrychium lunaria)

Field Cow-wheat (Melampyrum arvense)

Text and photos: Jasmin Inkinen, Archipelago Research Institute’s preparator

This is a short version of the original Finnish blog post, see the original post here.

See also: Natural environments in Seili (part 1)

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