Distribution and fishery of the invasive blue crab (Callinectes sapidus) in Turkey based on local ecological knowledge of fishers.
This study provides information on the distribution and ecology of Callinectes sapidus in Turkey, as well as its maximum daily catch in set nets (trammel nets and gillnets), and its commercial fishery in lagoons. Data were collected in 2020 by utilizing a telephone based questionnaire survey. Responses were gathered from fishers (n = 6) who fish in the lagoons and the head of fishery cooperatives or its members (n = 104) in 28 cities, including the coastal regions of the Mediterranean Sea (Levantine), Aegean Sea, Sea of Marmara and the Black Sea in Turkey. Results indicated that C. sapidus is commonly distributed along the Levantine and Southern Aegean coasts of Turkey, whilst it is rarely observed in the Sea of Marmara and the Black Sea. It has been reported by fishers that this species has been seen in the Black Sea for the last decade. The maximum daily catch of blue crab in set nets showed a significant difference in the Levantine and Aegean coasts. The species is mainly produced in the lagoons, whereas many coastal fishers returned it as discard and 79% of fishers emphasized that C. sapidus shred the nets and caused an economic loss. Ovigerous females have been observed between March and October and we have discussed related management issues including current fishery season.