Snapshots of past fish faunas: paleo-oceanographic perspectives from the Baltic and Black Seas

Analyses of fish remains from sediment cores make it possible to detect not only commonly caught fish from prehistoric times, but also species without any economic importance, though of significance value of palaeoecological reconstructions.In this study, fish bones from sediment cores reaching as far back as several thousand years ago and taken in the Baltic and Black Seas were analysed. All fish remains examined postdate the last glaciations and are from the last marine/brackish stages of both seas.In the Baltic cores, over 13 species were found, the most abundant ones being sand-eel and clupeids (herring and sprat). Flatfish (flounder) was mostly only present in the core taken near Bornholm. One layer in a core from Gotland Deep was especially rich in bones from juvenile sand-eel, with 1 g of material containing over 265 individuals.In the Black Sea cores, more than 5 different species were found: sprat, anchovy, whiting, Mediterranean sand-eel and several nearly complete pipefish which could be identified to the endemic Syngnathus schmidti.The cores from the two seas exhibit common features. All species found were euryhaline, and species that are commercially important today were documented back in time before industrial fishing for them began.The results of this study leads to methodological recommendations regarding dating of material from sediment cores and retrieval of fish remains.