Researchers using a custom ROV explored Caprera Canyon, a biodiverse submarine valley 20–40 km off Sardinia, from 130 to 1,050 m, documenting rare corals, sponges, fish and repeated Mediterranean monk seal sightings alongside plastic and lost fishing gear. Teams combined ROV imagery with eDNA, zooplankton and hydrophone sampling (≈40-minute recordings at ~20 m) and chemical analyses that revealed persistent pollutants such as DDT. Designated a 2024 Mission Blue Hope Spot, the canyon is now the focus of parallel bids for IMMA, FRA and MPA protections, with an FRA proposal planned for 2026.
Caprera Canyon: Mediterranean’s Hidden Undersea Valley Teeming with Life — Now Under Threat
Researchers using a custom ROV explored Caprera Canyon, a biodiverse submarine valley 20–40 km off Sardinia, from 130 to 1,050 m, documenting rare corals, sponges, fish and repeated Mediterranean monk seal sightings alongside plastic and lost fishing gear. Teams combined ROV imagery with eDNA, zooplankton and hydrophone sampling (≈40-minute recordings at ~20 m) and chemical analyses that revealed persistent pollutants such as DDT. Designated a 2024 Mission Blue Hope Spot, the canyon is now the focus of parallel bids for IMMA, FRA and MPA protections, with an FRA proposal planned for 2026.
09:17 PM, 11/17/2025Environment
Caprera Canyon: a rich but endangered undersea valley
One thousand meters (3,281 feet) beneath the Mediterranean, researchers filmed a crab ensnared in plastic struggling across a rocky seafloor. At about 240 meters (787 feet), bamboo coral colonies were being smothered by abandoned fishing gear. These stark images came from a recent expedition into Caprera Canyon, a vast submarine valley located roughly 20–40 kilometers (12–25 miles) off the coast of Sardinia, Italy.
Caprera Canyon is one of the Mediterranean’s largest and most biodiverse deep-sea systems. It cycles nutrients, stores carbon and provides habitat for corals, sponges, fish, turtles, sharks and dolphins — and, increasingly, for the endangered Mediterranean monk seal.
"At the moment, the canyon has no kind of protection at all, so we are going to lose refuge for so many endangered species and we will lose a lot of biodiversity," said marine biologist Ginevra Boldrocchi, scientific project coordinator for One Ocean Foundation.
In June, One Ocean Foundation, supported by the Rolex Perpetual Planet Initiative and joined by CNN, deployed a custom remotely operated vehicle (ROV) to survey habitats from roughly 130 to 1,050 meters (427 to 3,445 feet). Piloted by sailor-turned-engineer Guido Gay, the battery-powered ROV recorded high-resolution video, collected specimens and sampled sediments from areas that humans had never seen.
Researchers documented rare sponge and coral communities, extensive fish life and repeated sightings of the endangered Mediterranean monk seal — evidence that the canyon may be an important feeding ground. They also recorded clear signs of human damage: lost and discarded fishing gear, litter and direct coral mortality. Francesco Enrichetti, a University of Genoa researcher on the expedition, noted that long fishing lines have destroyed delicate soft-bottom gorgonians that form tree-like habitat for many species.
How scientists are studying the canyon
Because much of the canyon’s deep waters are inaccessible to divers, the team combined deep ROV surveys with surface and mid-water sampling. Methods included:
- Environmental DNA (eDNA) sampling to detect biological traces in seawater and infer species presence.
- Zooplankton collection to monitor pollutants and serve as indicators of ecosystem health.
- Hydrophone deployments about 20 meters (66 feet) below the surface with ~40-minute recordings to capture marine mammal vocalizations and measure noise pollution from shipping.
- Chemical analyses testing for heavy metals (mercury, cadmium, arsenic, iron, zinc) and persistent organic pollutants such as DDT — traces of which persist decades after bans and can disrupt growth and reproduction.
Back on land, scientists reviewed the ROV video and samples and confirmed both ecological richness and the negative impacts of human activity. Their findings strengthen the case for formal protection.
From discovery to protection
Caprera Canyon was named a Mission Blue Hope Spot in 2024. Building on that recognition, One Ocean Foundation and collaborators plan to pursue multiple layers of protection in parallel: Important Marine Mammal Area (IMMA) recognition, a Fisheries Restricted Area (FRA) designation, and ultimately a Marine Protected Area (MPA). The team intends to use ROV imagery and collected data to support an FRA proposal to Italian and EU authorities in 2026.
Boldrocchi emphasized the role of technology in conservation: "We need to see, to connect, to understand the environment in all details in order to protect it." The Caprera expedition shows that targeted scientific exploration can reveal both the hidden richness of deep-sea ecosystems and the urgent threats they face.
What’s next: continued ROV surveys, expanded eDNA and chemical monitoring, and coordinated policy efforts aimed at securing protections that would limit harmful fishing practices, reduce pollution and help the canyon’s species — including the Mediterranean monk seal — recover.