NW Mediterranean PSSA: voluntary whale-strike speed advisory

The IMO-designated Particularly Sensitive Sea Area recommends vessels of 300 GT and above reduce speed to 10–13 knots to prevent lethal strikes on fin and sperm whales.

On 7 July 2023 the IMO designated the North-Western Mediterranean Sea as a Particularly Sensitive Sea Area (PSSA), on a joint proposal by France, Italy, Monaco and Spain, to reduce lethal ship strikes on endangered fin and sperm whales. The area hosts an estimated 67% of the Mediterranean fin whale population and overlaps the Pelagos Sanctuary and the Cetacean Migration Corridor (a SPAMI).

The Associated Protective Measure applies to commercial ships and pleasure craft of 300 GT and above. Mariners are recommended to navigate with particular caution and, where cetaceans are detected or reported, to voluntarily reduce speed to 10–13 knots, while always maintaining a safe speed for manoeuvring. The measure is currently voluntary, not mandatory.

Operational note: reducing speed to about 10 knots is the single most effective way to lower the probability of a lethal collision and also cuts underwater radiated noise. Masters transiting the corridor should brief the bridge team, mark the PSSA boundaries on ECDIS and record speed decisions in the log.

Practical takeaway: fleet-wide voluntary compliance remained low through 2023–2024 and regulators are discussing mandatory limits. Operators who adopt the advisory now reduce environmental risk and their reputational / ESG exposure ahead of any binding rule.