_{Image1: Common dolphin (Delphinus delphis) in the Bay of Biscay in Autumn 2021 © Observatoire Pelagis, Image 2: Common dolphin (Delphinus delphis) in the Bay of Biscay in Autumn 2021 © Observatoire Pelagis, Image 3: Grey seal (Halichoerus grypus) off Brighton Beach © Olle Akesson}

Harbour porpoise distribution shifted southward within the Greater North Sea. Abundance appears stable except for a decline in the Irish and Celtic Seas. Assessed populations of coastal bottlenose dolphin appear stable except for a decline in the Sado Estuary. Overall, more frequent large-scale surveys are needed for future quantitative assessment.

This assessment concluded by-catch is a significant pressure affecting marine mammal (Harbour Porpoise; Common Dolphin; Grey Seal) populations in the North-East Atlantic (Greater North Sea (Region II), Celtic Seas (Region III), Bay of Biscay and Iberian Coast (Region IV)), with harbour porpoise and common dolphin exceeding the thresholds. Grey seal did not exceed the thresholds.

The assessment is underpinned by a conservation objective attempting to capture European ambition for by-catch levels, subject to adjustment for future assessments to accommodate new evidence

Marine mammal by-catch is a significant pressure affecting populations in the North-East Atlantic. In Arctic Waters (Region I), a Pilot Assessment was possible for two species (harbour porpoise and grey seal) in the Iceland Assessment Unit (AU) based on the US conservation objective (PBR), resulting in grey seal exceeding and harbour porpoise not exceeding the threshold value.

OSPAR is the mechanism by which 15 Governments & the EU cooperate to protect the marine environment of the North-East Atlantic.