The silent inhabitants of the Mediterranean: A sea’s vanishing species

When we look at the Mediterranean, what we usually see is blue. Yet beneath that blue lies a far greater world, hidden from our eyes. Within the mere few seconds of a wave crashing onto the shore lies millions of years of evolution, a complex web of life connecting thousands of species, and an increasingly gruelling struggle for survival.

The Mediterranean is one of the world’s key areas of biological diversity. According to IUCN assessments, around 6,000 species in the region have been assessed, and approximately a quarter of these are classified as threatened. The fact that it is a semi-enclosed sea, combined with dense coastal settlement, tourism, fishing, maritime traffic, pollution, invasive species and climate change, is increasing the pressure on the Mediterranean.

It is not only the ‘cute’ or easily recognisable creatures that are under this pressure. Corals, seagrasses and giant mussels – which are no more visible than a seal, a sea turtle or a dolphin – are also indispensable parts of the same ecosystem.

For some, however, the issue is no longer merely the shrinking of their habitats. It is the risk of extinction.

The Mediterranean monk seal: The silent inhabitant of the caves

One of the Mediterranean’s most iconic creatures is undoubtedly the Mediterranean monk seal (Monachus monachus).

Once found across a much wider area of the Mediterranean, this species is now confined to caves on rocky coasts and hard-to-reach coastal areas, far from human activity. According to the IUCN’s 2026 assessment, the global population is estimated to be approximately 800–1,000 individuals. Although the species’ global IUCN status was upgraded to ‘Vulnerable’ (VU) in 2023, its status in the Eastern Mediterranean is still classified as ‘Endangered’ (EN).

The situation is of even greater significance for Turkey. The Mediterranean Conservation Association reports that a significant proportion of the population in Turkey forms part of the Eastern Mediterranean population, and estimates suggest there are approximately 42–120 adult individuals in the country.

The seals’ problems are not confined to the sea

The coastal caves they use for breeding and resting are under pressure due to tourism, development, boat traffic, diving and human interference. Entanglement in fishing gear, the depletion of food sources, pollution and poaching are also among the threats facing the species.

For this reason, protecting the seal is as much about protecting the entrance to a cave as it is about protecting the sea surrounding that cave.

The Mediterranean Conservation Association, one of the organisations working in this field in Turkey, has been monitoring the caves along a coastal strip stretching approximately 710 kilometres from the Gulf of Gökova to Kaş-Kekova using camera traps and real-time camera systems since 2016.

The ODTÜ Institute of Marine Sciences has also participated in international projects aimed at the conservation of Eastern Mediterranean monk seals.

One of the studies conducted by the Institute aimed to monitor seal populations, reduce threats and develop joint monitoring methods in collaboration with partners in the Mediterranean.

TÜDAV, meanwhile, has been monitoring seal habitats for many years; it carries out research on caves, installs monitoring devices inside them, collaborates with fishermen and runs public awareness campaigns.

In other words, seal research does not merely seek to answer the question ‘how many seals are there?’. The real question is:

Is there still a Mediterranean where seals can survive?

Sea turtles: A struggle stretching from the beach to the open sea

Another symbol of the Mediterranean is the loggerhead sea turtle (Caretta caretta). The beaches along Turkey’s Mediterranean coast are among the most important breeding grounds for this species. It is estimated that there are approximately 2,000 adult female Caretta caretta nesting in the Mediterranean.

Another important species is the green sea turtle (Chelonia mydas). It is classified as ‘Endangered’ (EN) on a global scale by the IUCN. Turkey’s Mediterranean coastline is home to important nesting sites for the Mediterranean population.

The story of these two species also illustrates just how complex conservation is. Protecting a turtle is not merely about protecting its nest. The hatchling must reach the sea, feed in the ocean, travel along safe migration routes, and be able to return to the breeding beach as an adult.

Moreover, the threats are quite diverse: coastal development, artificial lighting, beach use, nest crushing, plastic and marine litter, entanglement in fishing gear, boat strikes and climate change.

Climate change, in particular, is especially critical for sea turtles. This is because the sex of sea turtle hatchlings is closely linked to incubation temperature. Consequently, long-term changes in sand temperature can affect the future of populations.

One of the most important research centres in Turkey is DEKAMER, the Sea Turtle Research, Rescue and Rehabilitation Centre.

The centre has been carrying out its work in Dalyan since 2009. It undertakes a wide range of studies, from treating injured turtles to monitoring nesting beaches, from tracking migration routes using satellite transmitters to conducting genetic research.

DEKAMER’s work also includes: nest fencing, the relocation of at-risk nests, research into embryonic development, sex determination, investigating the effects of plastic pollution, and researching fishing-related deaths.

The Middle East Technical University (METU) Institute of Marine Sciences is also carrying out long-term monitoring studies at one of Turkey’s key sea turtle nesting sites. The Institute’s programme has aimed to conduct regular monitoring since 2013.

What the scientists do here is actually much more than simply walking along the beach at night.

Every track left in the sand, every nest dug, every hatchling reaching the sea and every adult turtle tracked is transformed into scientific data for the future.

Pinna nobilis: The silent decline of the Mediterranean’s giant

One of the most striking losses in the Mediterranean is occurring in a creature whose name most people do not even know: Pinna nobilis, a giant bivalve native to the Mediterranean, known in Turkey by various names such as ‘pina’ or ‘deniztarağı’.

This creature, which can exceed one metre in size, lives on the seabed, particularly amongst Posidonia oceanica seagrass meadows. It helps to clean the water through filtration, and its shell provides a habitat for numerous other organisms.

However, a horrific wave of mass mortality began in the Mediterranean after 2016.

A vast proportion of populations were lost in various regions, particularly in Spain. The spread of a parasite called Haplosporidium pinnae, associated with the disease, has seriously threatened the species’ future. The IUCN has listed Pinna nobilis as Critically Endangered (CR).

Today, scientists are not merely counting the dead individuals. What they are really looking for are the individuals that have managed to survive.

Research published in 2025 and 2026 revealed that small but resilient communities of Pinna nobilis can still be found in some lagoons and coastal areas of the Mediterranean. Consequently, research is now focusing on genetic diversity, disease resistance, eDNA, the monitoring of remaining populations and potential restoration methods.

This story highlights an important reality of the Mediterranean: sometimes the extinction of a species does not happen with a great deal of fanfare.

One morning, when we look out to sea, we might not notice anything amiss. But on the seabed, an area that was once home to hundreds of individuals may have quietly been emptied.

Red coral: The Mediterranean’s slow-growing forests

The Mediterranean’s corals are also under pressure. One of the best-known is the red coral (Corallium rubrum). The IUCN assessment classifies this species as ‘Endangered’ (EN), noting that its populations have suffered significant declines in the past. Overharvesting, poaching, habitat destruction and rising sea temperatures are among the main threats.

To understand the fragility of coral, we need to rethink our concept of time.

A coral colony grows over years, even decades. In contrast, it can be damaged in a matter of seconds by a dive, anchoring or illegal harvesting.

The IUCN’s assessment of Mediterranean corals states that a significant proportion of the anthozoan species examined are under threat, and that there is still insufficient data available for many species.

This demonstrates that conservation efforts must not only protect existing species but also involve discovering those we do not yet know well enough.

Posidonia: Not a fish, but a home for fish

One of the Mediterranean’s most important organisms is also one of the most misunderstood: Posidonia oceanica. Despite the ‘oceanica’ in its name, it is not an ocean plant; it is a marine flowering plant endemic to the Mediterranean – in other words, a seagrass. And it is, in fact, much more than just a seagrass.

Posidonia beds provide shelter and feeding grounds for fish and invertebrates, help protect coastlines against erosion, store carbon and play a vital role in the productivity of the marine ecosystem. Studies by the IUCN emphasise that Posidonia is one of the critical ecosystems for the resilience of the Mediterranean coastline.

However, an anchor dropped onto the seabed, coastal construction, turbidity, pollution and physical damage to the seabed can fragment these meadows. Moreover, the regrowth of Posidonia is not as straightforward as replanting a lost patch of grass.

For this reason, the IUCN’s Posidonia projects are developing management models aimed not only at protecting the plant itself, but also the natural banquettes—that is, the organic accumulations along the coast—formed by the leaves Posidonia carries ashore.

At this point, we encounter a very significant misconception: the dried Posidonia leaves we see on the shore are not ‘rubbish’; they are part of the coastal ecosystem.

Dolphins and whales: The Mediterranean’s hidden migration routes

The Mediterranean is not only a habitat for seals but also for numerous species of dolphins and whales.

Species regularly or occasionally sighted in Turkish waters include the common dolphin, the harbour porpoise, the striped dolphin, the grampus, the sperm whale, the beaked whale and the fin whale.

However, one of the biggest challenges regarding marine mammals is that their populations cannot be monitored as easily as those of land-dwelling animals.

Whilst it is difficult to count how many deer there are in a forest, determining how many dolphins are present in a sea covering thousands of square kilometres is far more complex.

For this reason, scientists use a combination of different methods, such as marine observations, photo-identification studies, acoustic monitoring, stranding records, genetic analyses and research into interactions with fisheries.

TÜDAV is one of the organisations conducting long-term studies on marine mammals in Turkey. The foundation monitors the distribution of marine mammals and stranding incidents; it also implements marine mammal action plans and carries out collaborative projects with fishermen.

This is because the cause of death of a dolphin at sea is often more than just ‘the death of an animal’. It may be a sign of larger issues such as entanglement in nets, overfishing, plastic and chemical pollution, underwater noise, vessel strikes and habitat changes.

What are scientists and civil society doing?

Conservation efforts in the Mediterranean do not rely on a single approach. On the contrary, protecting a species requires different disciplines to come together around the same table.

Middle East Technical University (METU) Institute of Marine Sciences

It is involved in conservation biology research, focusing primarily on seals and sea turtles. Whilst participating in international partnerships for population monitoring and threat mitigation in seals, it conducts long-term nesting site monitoring studies for sea turtles.

DEKAMER

One of Turkey’s most comprehensive research, rescue and rehabilitation centres for sea turtles. It carries out multifaceted work including the treatment of injured animals, nest protection, satellite tracking, genetic research, pollution studies and investigations into fishing-related deaths.

Mediterranean Conservation Association

It focuses on the Mediterranean monk seal and other vulnerable marine species, as well as their habitats. It carries out studies including seal monitoring using camera traps, monitoring of marine protected areas, monitoring of fish biomass and macroalgae, monitoring of sea water temperature, and work related to sustainable fisheries.

TÜDAV

It carries out research, monitoring, education and public awareness campaigns across a wide range of marine biodiversity, from Mediterranean monk seals to dolphins and whales, and from sea turtles to sharks. These activities include the study of seal habitats, cave monitoring, collaboration with fishermen and the monitoring of marine mammal stranding incidents.

IUCN Mediterranean Programme

It assesses the status of species and ecosystems at a regional scale, carries out Red List work, contributes to the planning of protected areas and develops projects aimed at reducing the impact of fisheries on vulnerable species. 

Protecting a species is not merely about protecting that species

When we look at the species in the Mediterranean individually, we see different stories. The seal needs a cave. The turtle needs a beach. Pinna nobilis needs seagrass beds. 

The red coral needs rocky habitats. Dolphins need vast, quiet marine areas. 

Posidonia, meanwhile, forms one of the links in the web of life for all these creatures. Consequently, none of these are independent of one another.

Development in a cove may not only affect the seal’s cave. It may also affect the Posidonia on the seabed, the fish’s breeding grounds, the food chain and, consequently, fisheries.

The loss of a seagrass meadow is not merely the loss of a plant.

A turtle swallowing plastic is not merely an unfortunate incident befalling a single animal.

A dolphin becoming entangled in a fishing net is not merely a death. Each of these is a small warning sign from the Mediterranean ecosystem.

The real issue: not losing the Mediterranean before we lose its species

Perhaps the most important aspect of conservation efforts comes to the fore here.

Conserving nature is not merely about ‘saving endangered animals’. Sometimes the way to save an animal lies in protecting the cave it inhabits; sometimes in leaving the beach undisturbed after dark; sometimes in casting an anchor in the right place on the seabed; and sometimes in bringing a fisherman and a scientist together around the same table.

The future of the Mediterranean is far greater than the fate of a few iconic species.

Because the sea is not merely the sum of individual living things.

The sea is the shared story of millions of lives bound together by invisible threads.

When one thread snaps, the net does not unravel immediately.

Then the second thread snaps.The third…One day, when we look back, we see that the sea is still blue, but we realise that the story within it has been diminished.

This is the hardest part of protecting the Mediterranean: extinction often comes silently.

That is why the records kept by scientists, the conservationists keeping watch on the shore, the volunteers who spend the night by the nests, the cameras placed in caves, the satellite transmitters and the divers monitoring the seagrass meadows on the seabed are not merely documenting the present.

They are mapping out a future that we have not yet lost.

Source note

Basic information regarding the conservation status and threats to the species mentioned in this article was compiled by cross-referencing current or institutional sources published by the IUCN, the Middle East Technical University (METU) Institute of Marine Sciences, DEKAMER, TÜDAV and the Mediterranean Conservation Association. Sources were cross-checked specifically for the Mediterranean monk seal, sea turtles, Pinna nobilis, corals and Posidonia.

References

• IUCN (International Union for Conservation of Nature), work on the conservation of the Mediterranean Monk Seal (Monachus monachus) and other species in the Mediterranean.
• IUCN Mediterranean Programme⁠
• Mediterranean Conservation Association, Mediterranean Monk Seal. The species’ population, threats, status in Turkey and monitoring studies using camera traps and real-time cameras. 
• Mediterranean Conservation Association, Marine Species. Projects focusing on the Mediterranean monk seal, sand tiger shark, seagrass beds and other marine species. 
• Mediterranean Conservation Association, About Us. Organisational information regarding the association’s science-based conservation, habitat restoration and coastal fisheries work.
• Middle East Technical University (METU) Institute of Marine Sciences, Conservation Biology. Projects concerning the conservation of seals and the long-term monitoring of sea turtles in the Eastern Mediterranean.
• DEKAMER (Sea Turtle Research, Rescue and Rehabilitation Centre), Areas of Work. Satellite tracking, genetic research, pollution studies, rehabilitation, nest protection, embryonic development and sex determination studies. 
• DEKAMER, Projects. Monitoring of sea turtles along Turkey’s Mediterranean coast, plastic pollution, bycatch and projects such as LIFE-MEDTURTLES.
• DEKAMER, Reports. Annual reports on research, rescue and rehabilitation work carried out since 2009. 
• DEKAMER, About. The centre’s establishment, remit, and scientific research and rehabilitation activities.
• TÜDAV (Turkish Marine Research Foundation), Marine Mammals of Turkey. Information on dolphin, whale and Mediterranean monk seal populations in Turkey and the Mediterranean.
• IUCN, Red List, Pinna nobilis. The conservation status and threats facing the Mediterranean giant clam.
• IUCN, Assessments on Mediterranean corals and Corallium rubrum.
• IUCN, Studies on the ecological importance and conservation of Posidonia oceanica and Mediterranean seagrass beds.