Three years ago, the eastern cod stock was in such bad shape that the Commission decided on an emergency closure of the fishery. Since then, only by-catches have been allowed.

Despite reducing fishing pressure, the cod has still not recovered.

Collapses in fish stocks are commonly blamed on overfishing. But for the eastern Baltic cod, this is not the case. Instead, the productivity of the stock sank. Expected growth did not materialize. 

What factors can explain the crash of the stock? Scientists are still trying to figure that out. It is important to understand, for example to be able to assess productivity and predict future developments of the stock. 

In this webinar we will look at one possible explanation: a narrower “ecological envelope” for the cod. In other words, a reduction of water volumes and seafloor areas with the right oxygen, salt and food conditions for the cod. 

To help us, we have two co-authors to an article published earlier this year.  

Henrik Svedäng will give us an overview of how the cod stock has developed over time in terms of reproduction and productivity (growth and survival), of some of the theories about its decline, and about how some of the aspects of the cod’s “ecological envelope” have developed. 

One of the explanations for the cod’s decline is that a lack of oxygen at the bottom of the sea has led to a lack of food. Anna Villnäs will tell us about research on the question: How has lack of oxygen at the sea floor impacted on benthic organisms over time in areas where the cod could be? Does the development of benthic organisms in cod areas suggest an indirect, negative impact of eutrophication on prey species?

Speakers

Henrik Svedäng, Researcher and Associate Professor, Baltic Sea Centre, Stockholm University

Anna Villnäs, Researcher in marine biology at the Tvärminne Zoological Station, Helsinki University

Practical information

This webinar is broadcasted on this webpage 31 August 2022, 8:30-9:15 (Local time in Sweden).

No registration is needed.

The webinar will be recorded and can be watched afterwards at this same webpage.

Questions and discussion

We highly welcome the audience to ask questions, in advance or during the webinar. E-mail your question to ostersjocentrum@su.se or use sli.do with code 22102

Discuss the topic on Twitter, using the hashtag #balticbreakfast

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About Baltic Breakfast

Baltic Breakfast is a series of short breakfast seminars/webinars organised by Stockholm University Baltic Sea Centre. Their aim is to present the latest knowledge about issues of central importance to the Baltic Sea environment. The webinars are addressed to people in different sectors working for a sustainable development in the Baltic Sea region and everyone interested in environmental issues of the Baltic Sea.

Most Baltic Breakfasts are held in Swedish, but sometimes they are targeted at an international audience and held in English. If you want to get invitations to the upcoming webinars or subscribe to our monthly newsletters, click here.