Important Marine Mammal Areas

The ocean is vast, so knowing where to act matters.

Important Marine Mammal Areas (IMMAs) are scientifically identified habitats essential to the survival and recovery of marine mammal species, helping guide conservation, management, and responsible ocean use.

323
IMMAs identified worldwide with 82 in the Atlantic Ocean
130+
Marine mammal species represented within IMMA habitats
11818614km²
is the size of the largest IMMA, the North Atlantic Humpback Whale Migratory Corridor
A chain reaction that starts with whales

Marine mammals play an important role in maintaining healthy ocean ecosystems. Protecting the habitats they depend on supports biodiversity, strengthens ecosystem resilience, and contributes to the ocean’s natural ability to regulate the climate. 

Whales

Mix and fertilise the ocean as they dive, swim, and surface

Phytoplankton

Microscopic plants that thrive in whale-enriched waters

Carbon absorbed

Ocean phytoplankton absorb CO₂ on a scale comparable to all land plants combined

IMMAs protects

Identify the habitats where conservation action can have the greatest impact

Visit the IMMA website
How does IMMA work

Every IMMA goes through a rigorous, independent selection process, here’s how an area moves from candidate to protected corridor.

Scientists identify candidates

Using four criteria: species vulnerability, distribution, key life cycle activities, and special attributes.

Areas are mapped and published

Added to the IUCN e-Atlas and a searchable database, independent of any political or economic pressure.

Protection Measures

Once identified, IMMAs can be prioritised for protection measures by governments, intergovernmental organisations, conservation groups, marine stakeholders, and the general public.

Mapping a critical ocean corridor

With 323 IMMAs already established across the Southern Hemisphere, scientists are now turning their attention to the Northern Hemisphere, nine ocean regions still to be fully mapped. The North Atlantic is one of the world’s busiest ocean regions, supporting intensive commercial shipping, fisheries, tourism, and recreational boating activity. With support from the yachting community and Water Revolution Foundation, 82 IMMAs have already been identified here.

Why did we choose the IMMA programme?

Highest scientific rigour

The IUCN’s highest-priority marine programme, led by independent scientists with no political or economic influence.

Multiplier effect

Each IMMA identified can catalyse marine protected areas, spatial planning, and conservation policy at national and international level.

Informing conservation policy worldwide

IMMAs have shaped conservation in Vietnam, Bangladesh, and Mozambique, and are used by the International Whaling Commission and the United States Navy.

Built for mariners

IMMAs give captains and maritime operators clear guidance on how to navigate responsibly through sensitive habitats.

Frequently asked questions

How do IMMAs differ from Marine Protected Areas?

IMMAs identify where protections are most needed, they represent the knowledge phase that precedes action. Marine Protected Areas are a governmental decision that follows IMMA identification. IMMAs are advisory, science-based, and independent; MPAs are regulatory.

Where are existing IMMAs located?

Since 2016, over 323 IMMAs have been identified across the Southern Hemisphere, in the Mediterranean, Pacific Islands, Indian Ocean, Southern Ocean, Australia and New Zealand regions.

How can crew members get involved?

Crew members can contribute through citizen science, sharing observations that feed directly into ongoing research. Speak to your captain or contact us to find out more.

What happens after the North Atlantic is fully mapped?

Eight ocean regions remain to be mapped globally. Once the North Atlantic is complete, efforts will move to those regions. A GPS navigation tool for captains is also in development to raise real-time awareness of IMMA locations at sea.

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