For the Provision of Data Collection in Turkish Waters: LOT 3: Research Programme on Blue crabs

Birleşmiş Milletler Kalkınma Programı – UNDP Destekli Proje, 2024 - 2025

This report presents the outcomes of a comprehensive study on the invasive blue crab (Callinectes

sapidus) and the native swimming crab (Portunus segnis) along the Turkish Mediterranean coast. The

work was carried out under Work Package 1 and encompassed fishery-independent sampling,

tagging activities, questionnaire surveys, and plankton monitoring to assess juvenile recruitment.

The study aimed to understand the spatial-temporal distribution, reproduction, and fisheries

interaction of these species and to generate recommendations for sustainable management.

Field activities were successfully executed across multiple sites including the Akyatan and Ağyatan

lagoons and the adjacent marine and riverine habitats. Trawl surveys were conducted monthly at

three different depth zones, while trap surveys were performed at six stations over 12 months

(Akyatan) and 8 months (Ağyatan), respectively. Megalopa surveys were performed biweekly

between July and December 2024 to assess juvenile recruitment. Additionally, 61 stakeholders

participated in a socio-economic and ecological questionnaire survey, exceeding the original target.