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Complementary science delivery for sustainable use of the Baltic Sea living resources - results by BONUS INSPIRE and BIO-C3 projects

The BONUS “Viable ecosystems” projects INSPIRE and BIO-C3 have generated significant new information about Baltic species and ecosystems over the past years. Complementary results from these projects show that regional stock recovery might not lead to recovery of cod in the whole Baltic Sea.

FIRST ABOUT… BONUS INSPIRE challenges the tacit assumption that fishes are distributed homogeneously within managements units. We investigate spatial patterns, their formation and their consequences for ecology and management of the commercially and ecologically important fish species Baltic cod, herring, sprat and flounder. Our toolbox consists of pilot ecosystem field surveys and a combination of modern techniques with traditional methods readily applicable in fisheries assessment and management advice. www.bonus-inspire.org BONUS BIO-C3 addresses the drivers and the role of biodiversity on all its biological scales – genetic, taxonomic, functional, habitat and ecosystem diversity. We aim to move away from a static to a dynamic system view incorporating environmental change as well as the potential for species acclimation and adaptation, and to thus provide an improved scientific basis for resource management. www.bio-c3.eu Complementary results show that regional stock recovery might not lead to recovery of cod in the whole Baltic Sea: Complementary BONUS INSPIRE and BIO-C3 work revealed that the percentage of “Eastern” Baltic cod in the separately managed Western Baltic increased substantially in recent years. BONUS INSPIRE found that besides this short-distance exchange around the island of Bornholm, only a small fraction of “explorers” conducts long trans-basin migrations. Thus, adult migrations probably do not contribute to whole Baltic scale re-distributions of cod. Moreover, BONUS BIO-C3 showed that Eastern and Western Baltic cod represent two distinct genotypes, and that limited genetic mixing occurs between them, likely due to local adaptations to their different environments. Overall conclusion: rescue from the neighbouring stock is unlikely in case of the collapse of one of the stocks, and regional stock recovery might not lead to recovery of cod in the whole Baltic Sea, but rather to regional regulation of stock size due to density-dependent processes. Currently, BONUS INSPIRE and BIO-C3 investigate together, if these density-dependent processes for cod are amplified by the shifted spatial distribution of sprat. Furthermore: BIO-C3, with a team involving 8 BONUS projects, is aiming to put the Baltic on the global map with the concept paper initiative “The Baltic Sea as time machine for the global coastal ocean”. We postulate that current conditions in the Baltic – large anoxic zones, low pH, a history of warming, eutrophication and fishing pressure – resemble conditions expected only for the future elsewhere. We also show that Baltic management has been effective in curbing some key pressures, and can serve as example for other world regions. Excerpts from a guest column article by Stefan Neuenfeldt, Henn Ojaveer, Jan Dierking, first published in the BONUS in Brief October 2017 www.bonusportal.org/inbrief Further information on BONUS INSPIRE and BIO-C3 projects: www.bonus-inspire.org | www.bonusportal.org/inspire | www.bio-c3.eu | www.bonusportal.org/bioc3 | www.bonusprojects.org

Keywords

Baltic Sea, Fisheries, Sustainable development, ecology, spatial patterns, marine, commercial fish species, Baltic cod, biodiversity, species adaptation, species acclimation, dynamic system view, resource management, policy, policymaking, Baltic species, ecosystems, regional stock recovery

Countries

Germany, Denmark, Estonia, Finland, Lithuania, Latvia, Poland, Sweden