Northwest Mediterranean Declared a Specially Sensitive Marine Area
The International Maritime Organization, affiliated with the United Nations, has officially designated the Northwest Mediterranean region as a Specially Sensitive Marine Area (ZMES). This designation follows a proposal from France, Spain, Italy, and Monaco and covers a corridor from the Catalonian coast to northern Italy, including Corsica.
Initial measures in this part of the Mediterranean aim to reduce ship collisions with large cetaceans, particularly sperm whales and fin whales, which suffer high mortality in these busy sea lanes. The core idea is to encourage a voluntary reduction in ship speeds, with the expectation that slower ships will lower the risk of deadly collisions and lessen environmental disturbances. As with many conservation efforts, the approach blends precaution with practical feasibility, and the enforcement relies on voluntary compliance rather than strict mandates in every case.
The IMO’s designation acknowledges that ship strikes are the leading human-caused cause of death for fin and sperm whales in this region. The area experiences heavy marine traffic, with around 220,000 vessels passing annually. Commercial ships typically travel at 14 to 20 knots, while faster high-speed craft can exceed 35 knots. This combination of density and velocity makes collision risk a persistent concern.
“Should have had”
Experts feel the designation marks a meaningful advance, but they emphasize that the speed-reduction measure needs to be binding to be truly effective. Nicolas Entrup, Director of International Affairs at OceanCare, a marine conservation organization, urged that the policy include mandatory elements to prevent deadly collisions with large whales. He notes that a fully implemented framework would help protect marine life while leveling the playing field for shipping companies. (OceanCare)
The lighted red line on maps marks the approved area, underscoring the geographic scope of the precautionary measures. (OceanCare)
Scientists acknowledge the difficulty of predicting whale sightings in real time across the Mediterranean corridor. In practice, the option for ships to alter course to avoid collisions is limited, so reducing vessel speed is viewed as the most viable risk-reduction strategy under the circumstances.
In November 2021, ACCOBAMS, the Scientific Committee for the Agreement on Cetacean Conservation in the Black Sea, Mediterranean and Contiguous Atlantic, recommended reducing speed when routes to physically separate whales from ships are not feasible. The International Whaling Commission’s Scientific Committee reached a similar conclusion in 2022, reinforcing the view that speed reduction is a central tool for lowering fatal collision risks. (ACCOBAMS; IWC)
By December 2022, Mediterranean states agreed to promote reduced vessel speeds as an operational measure with multiple environmental benefits, including lower underwater noise and reduced greenhouse gas emissions. The plan also supports the broader proposal for a ZMES in the Northwest Mediterranean. (Mediterranean States Conference)
“Greatly Needed Safeguards”
The safeguards apply to merchant ships and pleasure craft with gross tonnage of 300 or more. While advisory in nature, they set a clear expectation that regulations will evolve over time. They encourage Wanderers to navigate with heightened care in the ZMES, especially in areas where large and medium cetaceans are present. A voluntary speed reduction to between 10 and 13 knots is proposed as an optional measure (VSR), provided that safety and maneuverability are not compromised. (Policy Briefs)
Carlos Bravo, representing OceanCare, commented that a measured speed reduction could effectively protect large whales while maintaining fair conditions for all shipping companies. (OceanCare)
IMO’s MEPC resolution for the ZMES notes the ongoing risk to cetaceans from ship traffic and emphasizes that without appropriate conservation measures, populations of medium and large marine mammals may decline. Implementing a speed-reduction strategy is expected to significantly reduce wildlife-related collisions and injuries. (IMO)
Description of the ZMES Field
The PSMA recommendation for the northwest Mediterranean outlines waters from Valencia to Genoa, identified as critical habitat for fin and sperm whales and noted for high environmental value. Notable zones include:
• Mediterranean Cetacean Migration Corridor, spanning the coasts of Catalonia and Valencia to the Balearic Islands, recognized as a Marine Protected Area by the Spanish government and as a Specially Protected Area for the Mediterranean under the Barcelona Convention. (Spain)
• Pelagos Marine Mammal Conservation Area in the Ligurian Sea. (Regional Authorities)
• IMMA areas and the so-called Lion’s Bay Shelf and the Northwest Mediterranean Canyon systems, highlighting important cetacean habitats. (IMMA)
In addition to fin and sperm whales, several other cetacean species frequent the Northwest Mediterranean PSMA throughout the year, including Cuvier’s beaked whale, pilot whale, bottlenose dolphin, striped dolphin, and common dolphin. (Marine Research Groups)
Concentration of Great-Finned and Sperm Whales
Within the ZMES, fin whales represent a substantial portion of the regional population. ACCOBAMS estimates in 2021 placed the fin whale population in this zone at roughly 67 percent of the broader Mediterranean total. For sperm whales, early estimates in the Pelagos Reserve and adjacent French waters suggested counts between 300 and 600, with higher numbers in winter. (ACCOBAMS)
From the mid-1990s to the mid-2000s, the Mediterranean experienced a sizable rise in maritime traffic and ship sizes. Projections indicate continued growth in routes and intensity as opportunities expand with canal traffic developments. (Regional Maritime Studies)
Additional notes and ongoing assessments support a cautious, adaptive approach to safeguarding cetacean populations in this dynamic sea area. (Conservation Assessments)