July 25th 2024

The Mediterranean Sea is changing due to human intervention and climate change and so are the species that live in it. This is mainly due to human induced factors such as overfishing and the desertification of many marine areas, but also due to the opening and widening of the Suez Canal, through which many alien species enter the Mediterranean. These, combined with climate change and as our seas are emptied of fish, lead to the creation of gap in ecosystems and favourable conditions for the spread of new species:

> 1000 alien species are found in the Mediterranean

> 1000 alien species have established viable populations

>100 are invasive and threaten marine biodiversity and ecosystem services

Help us record the spread of invasive species!

When swimming, diving or fishing, each of us can each spot an invasive or alien species.

Your observations are valuable and your questions are welcome.

Send your photos and reports to the Archipelagos’ Citizen Science Observatory: observations@archipelago.gr

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In order to learn to live with the new conditions that are emerging, which are ultimately the result of our way of life, it is necessary to start getting to know the various new species living in our seas.

– The bigfin reef squid (Sepioteuthis lessoniana) is the only alien squid species found so far in our seas

– The silver-cheeked toadfish (Lagocephalus sceleratus) is one of the most harmful invasive species in the Mediterranean, due to its wide distribution, the neurotoxin in its body which is dangerous to humans and makes it unfit for consumption, but also due to its impact on marine biodiversity and fisheries.

Dozens of young toadfish were found in the stomach of the Dolphinfish (see photo) caught in the Aegean Sea. Overfishing of predators is one of the main factors that enhances the spread of alien and invasive species!

– The Lionfish (Pterois miles) lionfish originates from the Indian Ocean and its spread is the fastest ever observed in the Mediterranean Sea. It can breed all year round and in the absence of natural predators, a drastic increase in its population is expected, as has been the case in many other seas around the world.

It is however a species that is safe to eat. Therefore, by choosing to fish, buy or consume lionfish, we are helping to control their populations, while at the same time supporting the income of fishermen, whom we must all help to adapt to the new conditions that are emerging in our seas.

(But be careful when handling the lionfish, the poisonous spines, which are on the dorsal and lateral fins, must be cut off).

– The jellyfish (Rhopilema nomadica) is a species formerly distributed only in the Indian and Pacific Oceans. Through the Suez Canal, it reached the Mediterranean waters in the 1970s, while in the Greek seas it was first recorded in 2006.

– The long-spined sea urchin (Diadema setosum) was first found in the Greek seas in 2010. It is a species that in previous years were recorded in Archipelagos Institute’s research in high densities from surface waters down to 95 m depth. Recently there has been a significant decline in the population of the species in the eastern Mediterranean.