C2 and 3 – The Central Baltic Sea

At the frontier between cold- and warm-water marine species

The fisheries characteristic

The Central Baltic Sea is the marine fisheries case study of the ClimeFish project in the Baltic Sea Region. The study area covers the ICES Sub-Divisions 25-29 and is the main fishing area for Eastern Baltic Cod, Central Baltic Herring, Baltic Sprat and several flounder stocks. The fisheries can be divided into three categories: inshore small-scale mixed fisheries, demersal fisheries targeting mainly cod and flatfish and pelagic fisheries targeting pelagic fish species, mainly sprat and herring.

Why climate change matters in this area

The Baltic Sea is a semi-enclosed, highly productive basin of the Baltic Sea with a low biodiversity, where only a few key species drive the system’s dynamics. Baltic Sea fish stocks are particularly sensitive for changes in climate and environment due to brackish waters conditions and large variations in salinity and temperature.

Recently, an ecosystem regime shift has been observed which have had pronounced effects at all trophic levels. The shift was driven by agriculture, fisher as well as climate change and has led to foodweb reorganisations and considerable changes in the ecosystem.

How ClimeFish will tackle climate-related issues

Data analyses will be performed to assess whether the following climate-related issues are affecting the Baltic Sea ecosystem, and by how much:

• Change in fish species distributions and stock dynamics
• Impact of fish stock recruitments (amount of young fish produced each year)
• Establishment and impact of non-indigenous species due to climate change

These issues will be included in a set of ecosystem models. The models will then be used to perform computer simulations to assess likely impact(s) on both the ecosystem and fisheries, and scenarios will be presented to design fisheries management strategies at a holistic ecosystem level. We hope that this work can support and improve the decision-making process.