The Mediterranean Sea is undergoing rapid ecological transformations driven by climate change and human-mediated species introductions. Among the most striking processes is the increasing arrival and establishment of non-indigenous species entering through the Suez Canal, a phenomenon known as Lessepsian migration.
A new study published in Acta Ichthyologica et Piscatoria documents the rapid expansion of the Indo-Pacific crab Gonioinfradens giardi in the Ionian Sea, off the coast of Italy. Following the first confirmed Italian record - a single specimen collected at Portopalo di Capo Passero in November 2025 - researchers documented 11 additional individuals between November 2025 and January 2026, providing early but compelling evidence that the species has moved beyond sporadic occurrence and may already be establishing stable populations in the region.
Our findings suggest that Gonioinfradens giardi is transitioning from occasional records to a more consistent presence in the central Mediterranean. This raises important questions about its potential ecological role and interactions with native species.
- explains Francesco Tiralongo, lead author of the study.
To reconstruct the current distribution of the species, the newly collected data integrates recent records with field observations obtained through a collaboration with local fishers utilizing standard artisanal fishing gears. The haul of a dozen individuals within a two-month period indicates that environmental conditions are becoming more favorable for its persistence. Furthermore, these captures mark the westernmost presence of the species in the Mediterranean Sea to date.
“The rapid emergence of this species highlights how dynamic and responsive Mediterranean ecosystems are to ongoing environmental changes,” adds Alberto Felici, co-author of the study. “Documenting these early phases of establishment is crucial for understanding future ecological scenarios and supporting informed management decisions.”
The establishment of non-indigenous crustaceans may have cascading effects on local ecosystems, including competition with native species and potential implications for fisheries. While the long-term impacts of G. giardi remain uncertain, its rapid spread reflects broader changes already underway in Mediterranean marine biodiversity.
This case adds to a growing list of species reshaping Mediterranean ecosystems. Continuous monitoring, including contributions from fishers and citizen scientists, will be essential to track these dynamics and support adaptive management strategies.
- Tiralongo adds.
The study contributes to the expanding body of evidence that the Mediterranean Sea is becoming a hotspot for biological invasions, emphasizing the need for coordinated research and monitoring efforts at regional and basin-wide scales.
Original source:
Tiralongo F, Leotta P, Accolla H, Tibullo D, Felici A (2026) Rapid expansion of a Lessepsian migrant crab, Gonioinfradens giardi (Crustacea, Brachyura, Portunidae), in the Ionian Sea: New records and early evidence of establishment. Acta Ichthyologica et Piscatoria 56: 145-149. https://doi.org/10.3897/aiep.56.185183