Alien Species

Alien Species in Aegean Sea

Many alien species have become invasive with substantial impacts on biological diversity, human health and ecosystem services.

Nevertheless, our knowledge of the effects of alien marine species on biodiversity and ecosystem services is mainly qualitative and largely based on weak evidence. The lack of precise knowledge about the life history traits of alien species and their invasive strategies constitutes a big obstacle to understanding their functional roles in the prevailing ecosystems and their impacts. An additional constraint to quantifying and mapping the impact of alien marine species is the lack of coverage and resolution in the available data (such as spatial distribution of native and alien species, habitat mapping), especially in data-poor regions such as the eastern Mediterranean.


Alien Species in Aegean Sea - Photo Gallery


Alien rhodophytes of the genus Asparagopsis have become common at many rocky reefs of the Aegean Sea.


The cryptogenic coral Oculina patagonica is similar to the Mediterranean endemic Cladocora caespitosa, and has a particular colonization preference for antropogenic hard substrate.


The alien holothuroidea Synaptula reciprocans forms large aggregations at regions of the southern Aegean and the eastern Mediterranean.

Several colorful Lionfish (Pterois miles) hunting at dawn on a shipwreck on a reef.

Bluespotted cornetfish (Fistularia commersonii) patrolling on a reefs’ edges.

The two siganids, Siganus luridus and S. rivulatus, have heavily grazed on Mediterranean macroalgal communities during the last decades.


The chlorophyte Caulerpa cylindracea has occupied a large space proportion of the pristine Mediterranean macroalgal community.


The alien blue crab Callinectes sapidus has become common catch at many Aegean regions, displacing economically valuable species.

The alien sea urchin Diadema setosum has become common at the rocky reefs of the southern Aegean

Lagocephalus Sceleratus


Sargocentron Rubrum

Torquigener Flavimaculosus