Identifying the environmental factors that influence the distribution of fisheries’ target species is essential for ecological modelling, an useful tool for the sustainable management of fisheries and the protection of essential fish habitats. The giant red shrimp Aristaeomorpha foliacea, is one of the most valuable fishery resources in the Mediterranean, particularly in the Ionian Sea, where significant changes in the abundance with time have been detected. Previous studies highlighted the role of environmental variables (sea-bottom temperature and fishing effort) in shaping the distribution of this species. Moreover, due to its feeding habits and its planktonic and epipelagic larval and post-larval phases, juveniles may be also exposed to the complex hydrological dynamics.

The Adriatic-Ionian Bimodal Oscillating System (BiOS) strongly influences the oceanographic circulation and variability in the central Mediterranean, and the reversals of the North Ionian Gyre (NIG) circulation, between cyclonic and anticyclonic, modify upwelling and downwelling rates, nutrient fluxes, and phytoplankton phenology. To test the effect of NIG reversals on the A. foliacea juveniles’ distribution, the North Ionian Gyre Index (NIGI) was computed analysing Multivariate Empirical Orthogonal Functions (M-EOF) of monthly historical time series (1987–2025) of environmental variables, derived from Copernicus Marine Service products. Moreover, considering the satellite-derived Chlorophyll-a concentrations (1999-2024) as a proxy for primary productivity, its interaction with the NIGI was tested using generalized additive models. The abundance of juveniles (carapace length ≤27 mm) was derived from the historical time series (1999–2024) collected during the Mediterranean International Trawl Surveys (MEDITS) in the North-Western Ionian Sea (Geographical Sub-Area 19).

The preliminary results showed a significant effect on juveniles’ abundances of the interaction term, acting as a modulating factor that provides a more comprehensive description of A. foliacea juveniles’ dynamics compared to the effect of single environmental variables. Further investigations are required to better understand these complex mechanisms.