Aquatic Sciences Meeting, Albuquerque 2001

PC17 Phytoplankton Physiology and Ecology

Date: Thursday, February 15, 2001

Location: Southwest Hall

Hjerne, O, , Deptartment of Systems Ecology, Stockholm University, Stockholm, Sweden, olle@system.ecology.su.se

Hansson, S, , Deptartment of Systems Ecology, Stockholm University, Stockholm, Sweden, sture.hansson@system.ecology.su.se

THE ROLE OF FISH IN NUTRIENT DYNAMICS OF THE BALTIC SEA

Many studies in freshwater show that fish can be important in nutrient dynamics, but similar reports from marine systems are scarce. We estimated the phosphorus sequestered from the water column into fish biomass in the brackish Baltic Sea proper. During summer, ~40% of the decrease in total phosphorus in the upper 40 meters can be explained by the build up of fish biomass. This suggests that fish might compete with primary producers, particularly cyanobacteria, for phosphorus. We also estimated that the removal of nutrients by the fishery landings constitutes 2.5% and 19% of the anthropogenic and bioavailable nitrogen and phosphorus load to the open Baltic Sea. These results show that fish can be important to nutrient dynamics even in marine environments, and this should be considered both in fisheries management and ecosystem analyses.

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Aquatic Sciences Meeting, Albuquerque 2001

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