No abstract

The diet composition of devil lionfish, Pterois miles (Bennet, 1828), from the Aegean Sea was investigated. The stomach contents of 42 samples (10 of which were empty) collected between May 2016 and November 2017 from Rhodes Island, Greece, were studied. The diet was composed predominantly of bony fish (78.5% in number, approximately 94.7% in biomass) belonging to a large variety of families, and invertebrates (15.4% in number, 5.1% in biomass), thus indicating an opportunistic feeding behaviour of the species in the study area. The length-length and length-weight relations were also determined.

The blue crab, Callinectes sapidus Rathbun, 1896, is native to the Atlantic coasts of the Americas and globally one of the most highly invasive marine species. In the present study, the species diet and the foraging behaviour was studied in the Thermaikos Gulf and Papapouli Lagoon for the first time. Surveys were undertaken using fyke nets, shore surveys, scuba and snorkelling. Additional data were compiled from systematic interviews with mussel farmers, shellfish traders and fishermen. In both Thermaikos Gulf and Papapouli Lagoon C. sapidus was found to prey on a wide variety of species including economically important molluscs, fishes, and crustaceans, indicating a substantial potential impact on fisheries and aquaculture in the region. Observation showed that over 6 (2009-2014) years, the blue crabs became dominant in Papapouli Lagoon at the expense of the native commercially fished crab Carcinus aestuarii Nardo, 1847 according to fisheries data. Potential management implications are discussed.