Spatial separation of larval sprat (<scp><i>Sprattus sprattus</i></scp>) and sardine (<scp><i>Sardina pilchardus</i></scp>) related to hydrographical characteristics in the North Sea

Abstract Clupeid fish species are widely distributed and of highly variable stock sizes. In the North Sea, common clupeid herring ( Clupea harengus ) sprat Sprattus sprattus ), but during recent decades, generally more southerly sardine Sardina pilchardus have been frequently observed. Comparative studies early life stages small pelagic clupeids scarce, their abilities to co‐exist relations environmental characteristics vastly understudied. We here investigated compared distributional patterns co‐occurring larval in hypothesizing that they separated into spatial niches linked specific hydrographical characteristics. Sampling was carried out by a large ring‐net standard surveys (IBTS Q3) August 2018, 2019, 2020. Sprat larvae were found widespread across area investigation, with highest concentration central Sea off eastern northern flanks Dogger Bank, where abundances could reach 20 larvae/m 2 . Sardine larvae, on other hand, showed Southern German Bights. Distributions two appeared complementary, statistical correlations indicative separate niches, resided relatively warmer fresher water. The relative versus varied between years. especially abundant 2020, twice as sprat, observations indicate increasing importance sardines Sea.