Abundance and population characteristics of the invasive sea urchin Diadema setosum (Leske, 1778) in the south Aegean Sea (eastern Mediterranean).

Background: The Indo-Pacific sea urchin Diadema setosum has invaded the Mediterranean Sea and has spread along many locations in the southeastern part of the basin, where established populations exist on the shallow subtidal rocky shore. Diadema setosum is a ubiquitous species, of particular ecological importance due to the high levels of grazing pressure it imposes on benthic communities. Its biology, however, is not adequately studied, especially along its introduced range of distribution.

Population Density, Size Structure, and Reproductive Cycle of the Comestible Sea Urchin (Echinodermata: Echinoidea) in the Pagasitikos Gulf (Aegean Sea).

is a common grazer that lives in various sublittoral habitats, displaying typical covering behavior; i.e., putts shell-fragments, pebbles, and algae on its test.

Climate change, biological invasions, and the shifting distribution of Mediterranean fishes: A large-scale survey based on local ecological knowledge.

Climate change and biological invasions are rapidly reshuffling species distribution, restructuring the biological communities of many ecosystems worldwide. Tracking these transformations in the marine environment is crucial, but our understanding of climate change effects and invasive species dynamics is often hampered by the practical challenge of surveying large geographical areas. Here, we focus on the Mediterranean Sea, a hot spot for climate change and biological invasions to investigate recent spatiotemporal changes in fish abundances and distribution.

Protozoan parasites in cultured mussels Mytilus galloprovincialis in the Thermaikos Gulf (north Aegean Sea, Greece).

The protozoans Ancistrum mytili (Oligohymenophorea: Ancistridae) and Marteilia refringens/maurini (Marteiliidea: Marteiliidae) were found parasitizing cultured mussels Mytilus galloprovincialis L. in the Thermaikos Gulf (north Aegean Sea, Greece). The former did not affect the condition index of infected mussels, in contrast to the latter, which did so and which also induced hemocyte infiltration in the affected digestive epithelium.