Ecological and Socio-Economic Impacts of Invasive Crustaceans on Sicilian Fisheries: Replacement of Native Species and Emergence of Novel Resources

Marine biological invasions are rapidly reshaping Mediterranean ecosystems, with growing consequences for biodiversity and fisheries. This study investigates recent changes in the composition of commercially important crustacean assemblages along the south-eastern coast of Sicily (central Mediterranean), focusing on penaeid shrimps (Penaeus aztecus and Penaeus kerathurus) and stomatopods (Erugosquilla massavensis and Squilla mantis). Field surveys were conducted during the fishing seasons of 2021 and 2025 at major landing sites and markets (Portopalo di Capo Passero, Syracuse and Catania), using standardized subsampling protocols applied to catches obtained by trammel nets and bottom trawls. Species composition was quantified through repeated sampling events, and temporal differences were analyzed using non-parametric tests and binomial generalized linear models, incorporating year and fishing gear as explanatory variables. Quantitative data were complemented by local ecological knowledge derived from structured interviews with professional fishers. Across the four-year interval, both taxonomic groups exhibited a pronounced shift in species dominance. The proportion of the invasive shrimp P. aztecus increased from approximately 20% in 2021 to over 80% in 2025, while the invasive stomatopod E. massavensis rose from about 2% to nearly 90% of total landings. These changes were statistically significant and independent of fishing gear. Fishers’ perceptions closely mirrored the quantitative trends, confirming the rapid replacement of native species by non-indigenous taxa and highlighting emerging socio-economic implications for local fisheries. Our findings document a rapid shift in the composition of commercial crustacean landings in Sicilian coastal waters, with invasive species becoming the dominant component of catches within a few years. This study underscores the need for adaptive fisheries management and integrated monitoring frameworks capable of responding to accelerating biological invasions in Mediterranean marine ecosystems.