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Turkish Journal of Zoology

Abstract

Rapid increases in the abundance and biomass of nonindigenous species have the potential to profoundly reshape demersal fish assemblages in the Eastern Mediterranean Sea, yet quantitative evidence from long-term standardized surveys remains scarce. In the present study, temporal changes in biomass dynamics and community structure were assessed using fishery-independent trawl surveys conducted on the continental shelf of Antalya Bay (GSA 24) during two periods a decade apart (2009–2010 and 2020–2021), with particular focus on the Lessepsian striped piggy Pomadasys stridens. Based on the second survey, in which both daytime and nocturnal sampling were conducted, the biomass index (BI) differed significantly between diel periods (p < 0.001), with higher and more variable BI values recorded during nocturnal hauls. Intersurvey comparisons based on nocturnal hauls revealed an approximately 33-fold increase in mean BI of P. stridens over the decade, from 11.9 to 410 kg km–2 (p < 0.001), while occurrence frequency increased from 75% to 100%. Total catch increased from 51.9 kg to 2260.6 kg between surveys. During the second survey, P. stridens accounted for 59.8% of the total teleost biomass and consistently emerged as the dominant contributor to within-season similarity across all seasons, explaining up to 75.6% of the community similarity in winter. PERMANOVA revealed significant seasonal differences in teleost biomass structure (p = 0.002), whereas diel effects were not significant. Generalized linear models confirmed a strong survey effect on BI with additional seasonal modulation, while environmental variability was primarily structured by seasonal rather than intersurvey differences. These results reveal a rapid and pronounced increase in the biomass and ecological dominance of P. stridens in Antalya Bay, suggesting that the region may represent a possible transitional zone facilitating the establishment and dominance of thermophilic and Lessepsian species in the ultra-oligotrophic Eastern Mediterranean.

Author ORCID Identifier

MEHMET DEVAL: 0000-0002-3112-0078

DOI

10.55730/1300-0179.3272

Keywords

Pomadasys stridens, invasive species, biomass index, demersal fish assemblages, Lessepsian migration, eastern Mediterranean Sea

First Page

295

Last Page

305

Publisher

The Scientific and Technological Research Council of Türkiye (TÜBİTAK)

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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