TROPHIC IMPACTS OF POISONOUS AND VENOMOUS LESSEPSIAN FISH SPECIES IN THE NORTHEASTERN LEVANTINE SEA: A COMPARATIVE FOOD-WEB MODELLING APPROACH

Date

2026-1-21

Author

Uysal, Aybüke

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The construction of the Suez Canal in 1869 permanently altered the biogeographic isolation of the Mediterranean Sea, triggering the ongoing influx of Indo-Pacific species known as Lessepsian migrants. In the Eastern Mediterranean, several Lessepsian species are also poisonous, introducing ecological and socio-economic pressures that extend beyond typical predator–prey competition. Despite their increasing abundance, the trophic consequences of poisonous Lessepsian fishes at the ecosystem level remain understudied. This thesis presents a comparative trophic assessment of poisonous Lessepsian and native fish species inhabiting the Eastern Mediterranean, with particular emphasis on the coastal ecosystems of Mersin Bay and the Adana coast. A mass-balanced Ecopath with Ecosim (EwE) model was developed for the 2023–2024 period by integrating trawl survey data and species-specific parameters from empirical and literature sources. Poisonous Lessepsian species, including Lagocephalus sceleratus, Lagocephalus guentheri, Lagocephalus suezensis, Torquigener flavimaculosus, Pterois miles, and Siganus luridus, were analyzed alongside non-poisonous Lessepsian and native fishes to evaluate direct and indirect trophic interactions. The results indicated that poisonous Lessepsian species exert disproportionately strong trophic effects on native fish communities, with the potential to reshape food-web structure. Accordingly, integrating these poisonous migrants into ecosystem-based assessments is essential for improving fisheries management, biodiversity conservation, and risk-informed decision-making in this rapidly changing marine region.

Subject Keywords

Eastern Mediterranean Sea, Lessepsian migration, Lagocephalus spp., Ecopath with Ecosim, trophic impacts

URI

https://hdl.handle.net/11511/118478

Collections

Graduate School of Marine Sciences, Thesis