The Archipelagos Institute of Marine Conservation has released captivating new footage of Risso’s dolphins (Grampus griseus), one of the least understood and most elusive cetacean species inhabiting Greek seas.
Unlike the playful, sleek-skinned dolphins often seen leaping near coastlines, Risso’s dolphins are creatures of the shadows. They are “deep-sea specialists,” preferring the rugged underwater topography of canyons and steep trenches.
One of their most critical habitats is the Ikaria Trench, a massive submarine chasm north of Ikaria island. It was here, in the autumn of 2000, that Archipelagos first recorded their migration—a breakthrough that sparked over two decades of systematic monitoring.
The new video highlights the species’ most striking feature: their heavily scarred bodies. Born a dark gray, these dolphins accumulate white linear scars throughout their lives from social interactions and battles with their primary prey, deep-sea squid. As they age, some individuals appear almost entirely white, earning them the nickname “ghosts of the deep.”
“Each sighting brings us one step closer to revealing the unexplored marine life of the Aegean,” the Institute noted. Because these dolphins are highly sensitive to human-induced threats—such as noise pollution from shipping and plastic ingestion—long-term research is vital. By using photo-identification to track the unique nicks on their dorsal fins, researchers can monitor population health and site fidelity without disturbing the pods.
This footage serves as a powerful reminder of the hidden biodiversity thriving just miles off the Greek coast. For the Archipelagos Institute, the goal is clear: to transform this scientific knowledge into a shield of protection for the Aegean’s deep-water wonders.
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