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Using otolith microchemical analysis to investigate the importance of brackish bays for pike ( Esox lucius Linnaeus, 1758) reproduction in the southern Baltic Sea
Author(s) -
Möller Sören,
Winkler Helmut M.,
Klügel Andreas,
Richter Stefan
Publication year - 2019
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/eff.12478
Subject(s) - pike , esox , brackish water , fishery , baltic sea , population , oceanography , otolith , ecology , environmental science , geography , biology , salinity , geology , fish <actinopterygii> , demography , sociology
The brackish Baltic Sea is inhabited by several primary freshwater fish species. The pike ( Esox lucius ) is the largest of these species and acts as the top predator in the marine food web of the Baltic Sea. Prior studies have shown the importance of brackish bays as spawning grounds for the Baltic Sea pike. To identify the spawning habitat of the pike population around the island of Rügen (southern Baltic Sea)—either freshwater streams flowing into the Baltic or brackish lagoons of the Baltic—we used the ICPMS method to quantify the strontium to calcium (Sr:Ca) ratios in sagittal otoliths of 79 adult pike. In total, only six per cent ( n = 5) of the analysed Baltic Sea individuals were classified as being of freshwater origin. Ninety‐four per cent ( n = 74) of analysed pike were classified as having hatched in brackish water. Compared to previous studies on Baltic Sea pike, our sample shows a high proportion of pike that is of brackish origin: this highlights the adaptive capacity of this species with regard to its ability to reproduce in different salinities. Our data highlight the importance of brackish bays for pike reproduction in the southern Baltic Sea, even if pike live on the upper limit of their salinity tolerance in this area. This is an important finding considering decreases in commercial catches in the last 30 years indicating a population decline supposedly related to recruitment failures.