July 21, 2026
At risk: Mediterranean corals
BY: Arin Owoturo
Topics: The Mediterranean Deep Sea
The Mediterranean Sea plays a vital role in supporting global biodiversity and regulating our climate. Despite occupying only 1.1% of the area of the world’s oceans and containing just 0.3% of all saltwater, it is home to a remarkable diversity of life. More than 200 species of corals live in the Mediterranean out of approximately 5600 species described worldwide.
The Mediterranean was once home to shallow-water, tropical coral reefs, which disappeared from its waters by approximately six million years ago, lost due to millennia of climatic and oceanographic changes.
However, even today this sea harbours a spectacular array of cold-water corals, some of which also form reefs. Mediterranean corals include species which are found nowhere else in the world, making the region particularly important for coral conservation.
What are corals and why are they important?
Corals are animals that possess a simple nervous system, grow and reproduce, and can live either in isolation or as part of large colonies. Some species display only their soft bodies, while others live inside hard protective tubes. While most tropical reef-building coral species contain microscopic algae that produce energy from sunlight, cold-water corals rely for food on plankton and other particles that they filter from the surrounding water.
All corals belong to the class Anthozoa, one of the oldest extant classes of animals on Earth. Their fossil remains can be traced back to the pre-Cambrian era, more than 500 million years ago, a period marked by a significant surge in oceanic life.
Corals are essential to the ocean’s health. The habitats they form host a wide array of ocean life, providing organisms with important areas for feeding, reproducing, and rearing their young, and acting as shelter from strong currents and from predators. They play a critical role in global food security, by supporting many species on which fisheries depend. They are also important for carbon cycling; cold-water corals in the Mediterranean, for example, can store large amounts of carbon within the structures that they build.
Threats to Mediterranean corals
Corals in the Mediterranean Sea face multiple threats, including:
Climate change
Climate change is intensifying pressures on Mediterranean coral ecosystems. Rising water temperatures, increasingly frequent and severe marine heat waves, and acidifying waters can have wide-ranging impacts. These include mass die-offs, increases in coral diseases and in non-native species that compete with native Mediterranean corals, and a reduced ability to recover from stress and damage. Climate-driven changes also affect the growth, survival, and recruitment of cold-water coral species, reducing the effectiveness of restoration efforts.
Fishing techniques
Deep-sea corals are highly sensitive to fishing impacts. Fishing techniques such as bottom trawling and other methods that require dragging nets across the sea floor pose a threat to these fragile animals. Even a single pass of a bottom trawl can cause significant damage, flattening centuries of growth. Bottom nets and long–lines can also become entangled in corals, breaking off pieces or causing other injuries (such as lacerations) that can allow pathogens to infect them.
Oceana campaigns for a transition away from destructive fishing practices such as bottom trawling and calls for its prohibition in all marine protected areas (MPAs) as well as in other sensitive zones, including deep-sea and coastal areas.
What kind of corals can be found in the Mediterranean Sea?
The Mediterranean hosts a diverse range of coral species, that comprise ‘hard’ corals, ‘soft’ corals, sea fans (gorgonians), and sea pens. Among the species observed during Oceana’s expeditions are:
Black coral (Antipathes dichotoma)
Red coral (Corallium rubrum)
Live colonies of the red coral Corallium rubrum have previously been recorded at depths of 600-800 m in the Strait of Sicily, but deep-water populations of this species remained poorly known. During Oceana’s research expedition around the islands of Malta, numerous colonies were observed in deeper waters, down to depths of 1016 m.
Red gorgonian (Paramuricea clavata)
Star coral (Astroides calycularis)
Oceana’s campaigns to protect corals in the Mediterranean
Oceana has researched and campaigned to protect corals for years, including little-known cold-water corals in unexplored waters of the Mediterranean Sea. Thanks to our research expeditions, we have surveyed these animals in the western, central, and eastern Mediterranean, at depths of up to one thousand metres.
Following our data collection and campaigning, in 2013 the EU agreed with the rest of Mediterranean countries to protect eleven species of deep-sea corals. In 2017, four more species were protected, including yellow tree coral (Dendrophyllia cornigera) and bamboo coral (Isidella elongata), a species that is mainly found in the Mediterranean and is Critically Endangered with extinction, primarily due to bottom trawling.
Currently, Oceana is campaigning for the protection of deep-sea corals across the Mediterranean, urging countries to extend the existing prohibition of bottom-fishing (which applies to waters below 1000 m depth) to include all waters below 800 m depth. On a local scale, the Cabliers Bank, which until recently, was a hidden jewel in the Mediterranean Sea, is now very close to being protected thanks to Oceana’s work. The reef, which lies in the Alboran Sea (the westernmost part of the Mediterranean) was discovered by Oceana during a research expedition in 2010. It is the only cold-water coral reef known to be growing in the Mediterranean and is remarkable for its near-pristine condition.
Given the importance of corals to Mediterranean marine ecosystems, and the uncertain future of many vulnerable species, Oceana proposes:
- Prohibiting the use of destructive fishing gear in marine protected areas with coral habitats.
- Prohibit all bottom contact fishing on coral seabeds.
- Reducing the impact of recreational activities on corals, including anchoring and scuba diving.
- Developing national evaluation and restoration plans for threatened species
- New marine protected areas to protect areas with coral reefs and of high biodiversity value.
- Make sure that at least 1/3 of each marine protected area is strictly protected to restore all the biodiversity associated to corals.
- Increase funding for underwater research to increase the mapping of coral reefs.
Take action! Tell the EU: save the Mediterranean Sea
