The use of otolith microchemistry to investigate spawning patterns of European anchovy: A case study in the eastern Ligurian Sea (NW Mediterranean)

Spawning patterns of European anchovy were investigated in the eastern Ligurian Sea (NW Mediterranean) by using otolith microchemistry. Otolith cores of 1-year-old anchovies showed a homogeneous chemical composition, while those of 2 years old anchovies separated into five different groups. This suggests the occurrence of single vs. multiple spawning areas related to the two annual cohorts. Patterns of core microchemistry of 2 years old anchovies support the hypothesis of different spawning areas, possibly characterised by different salinity regimes, in the eastern Ligurian Sea (e.g. typical marine habitats like shelf edges vs. lower salinity locations like river mouths). Results suggest that: (1) stocks of European anchovy could depend on different spawning areas characterised by different environmental conditions; (2) patterns may change from year to year, and this could affect the annual risk of stock fluctuations or collapse; and (3) the use of otolith microchemistry is a promising approach for investigating spawning patterns of European anchovy.

► Stocks of European anchovy are subject to fluctuations and collapses.
► Otolith core microchemistry was used on anchovy in the Ligurian Sea.
► Anchovy stocks can be replenished by single or multiple spawning areas/habitats.
► Patterns may change year by year and this may affect the risk of stock collapse.