Ecology of mysid shrimps in the Bornholm Basin (central Baltic Sea)

International audienceMysid shrimps are an important trophic link in the food web of the Baltic Sea. In 2002 and 2003 we investigated species composition, distribution, life cycle and prey in the Bornholm Basin (central Baltic). Three species and one genus were identified: and sp The dominant and occurred in the whole study area but were more abundant in the peripheral, more shallow regions. Size frequency distribution indicated one generation for and probably two for Main prey of all size classes in both species was the cladoceran during summer and autumn. In spring and winter also copepods of the species and were important prey items. Detritus and phytoplankton cells were of minor importance and many individuals had empty guts. Mysid shrimps in the deep basin might be advected from more shallow areas, as the abundance of all species was much lower than in coastal regions. The deep Bornholm Basin does not seem to be a favourable habitat, probably due to the inaccessibility of the oxygen deficient bottom layer. Under current hydrographic conditions mysids are probably not important predators of zooplankton and thus not competitors of planktivorous fish in the Bornholm Basin