Marine Invasive Alien Species Reshape Small-Scale Fisheries: Case Study in Greek Coastal Waters

The spread of non-indigenous species (NIS) in the Mediterranean poses complex challenges for coastal fisheries, yet the perceptions and adaptive responses of small-scale fishers remain poorly understood. This study surveyed 70 professional fishers across Greek insular and mainland ports to assess fishers’ local ecological knowledge, awareness, and operational strategies related to eleven established marine NIS. Semi-structured interviews recorded demographic and effort profiles, recognition rates, perceived environmental and economic impacts, catch frequencies, gear damage, injury incidents, and behavioral changes. Fishers in the study area demonstrated high overall awareness (~95%), but variable recognition of less familiar taxa (e.g., bigfin reef squid, squirrelfish). Venomous and gear-damaging species (pufferfish, lionfish, rabbitfish) were predominantly viewed negatively, with significant reported gear losses (EUR 600–1345 yr−1) and avoidance of high-incidence areas (25–30% of respondents). Conversely, commercially valuable NIS received more positive appraisals and are increasingly targeted. Spatial heterogeneity in perceptions and adaptations underscores the need for regionally tailored management that integrates fishers’ knowledge, promotes safe handling and selective exploitation of marketable NIS, and supports adaptive governance to mitigate ecological risks while enhancing socioeconomic resilience.