Alien fish species in the North Aegean Sea: a review of their distributions integrating unpublished fisheries data

Abstract

Abstract Fisheries-dependent data and information gathered through fisheries-related scientific surveys can significantly contribute to researching the patterns and processes underlying marine biological invasions and their interactions with fisheries. This study presents an overview of the presence of non-indigenous (NIS) fish species in the North Aegean Sea, offering insights into their distributions and impact on fisheries. The findings are based on a comprehensive compilation of commercial fisheries-dependent and scientific survey data collected in Greece from 2016 to 2023, along with an up-to-date systematic review of the international scientific literature. The study resulted in the identification of 37 non-indigenous fish species, including several recorded for the first time in the area. The results suggest that fish NIS invasions in the North Aegean Sea are dynamic: While most species were classified as casual, and the frequencies of occurrence as well as the quantities in commercial fisheries catches of established species are smaller than in the South Aegean Sea, an increasing trend in species introductions, extent of occurrence, and the area of occupancy of several species was identified. The significance of non-indigenous fish species is growing in relevance to commercial fisheries in the study area, especially in the Northeastern Aegean Sea. There, fish NIS catches are increasing, and new species of potential commercial interest have emerged in the last few years.