Marine Protected Areas & IMMAs

How much of the ocean is currently protected?

Less than 8% of the ocean is currently protected, with less than 3% of the ocean classified as highly protected from fishing impacts (Marine Protection Atlas 2021), as fully protected marine reserves (IUCN Category IA). The commitment to protect 30% of the ocean by 2030 is part of a global initiative to help prevent ecological collapse of the world’s ecosystems.

Proposed targets to protect 30% of land and 30% of the ocean by 2030 are non-binding however, many countries, governments and organisations have already pledged to conserve the planet’s natural areas to help curb climate change and biodiversity loss.

Indigenous communities, representing 5% of the population, as custodians of more than 25% of the land and ocean, protect 80% of global biodiversity. The #30×30 project respects Indigenous Peoples and Local Communities rights over their lands, territories and resources.

Marine protected area management is an effective tool to achieve the goal of protecting 30% of the ocean by 2030. Seafood Free September supports marine protected areas as effective management tools in the establishment of fully protected marine reserves to increase fish stocks and ensure sustainability of the marine environment for future generations.


Classification of marine protected areas (MPAs)

The International Union for Conservation of Nature (IUCN) classification system for defining protected areas is the global standard in marine and terrestrial protected area management. There are 7 categories of protected area, classified by the management objective (IUCN 2021).

The term ‘marine protected areas’ describe designated areas of ocean or marine environment with specific levels of restriction on human activity, and an overarching goal of conservation. Different types of MPAs are recognized by governments and international organizations – marine reserves, marine parks, marine sanctuaries and other special zones of protection.

Marine protected areas may fall under one category or, if an MPA is divided into zones, each zone may be classified under a different category. The terms ‘marine protected area’, ‘marine reserve’, ‘marine park’ and ‘marine sanctuary’ are often used interchangeably, but how an MPA is defined is irrelevant – it is the management objective that is important.

Marine reserves are MPAs with full IUCN Category IA protection from extraction of mineral resources (oil and gas) and marine life (fishing), except for the strict purposes of scientific research and environmental monitoring. Marine reserves are often called ‘no-take’ zones. This is the highest level of protection, yet only 3% of the ocean is protected at this level.

Marine parks are MPAs like terrestrial protected areas (national parks), where conservation is necessary to sustain the entire range of marine species, habitats and ecological processes characteristic to a particular area. Marine parks fall under IUCN Category II protection.

Marine sanctuaries are MPAs where marine habitats and marine species are protected from human impact. Marine sanctuaries may function as refuges for sharks and cetaceans where fishing is banned, as breeding grounds and nurseries for whales to calve their young, or places where marine habitats, including rocky reefs, coral reefs and kelp forests, can thrive.

World Heritage List status may be granted to a marine protected area with high cultural and ecological value if it fulfils at least one of ten selection criteria for inclusion on the list. The Great Barrier Reef is both a World Heritage listed site and a Marine Park, and nearly 99% of its World Heritage Area lies within the boundaries of the Marine Park (GBRMPA 2021).

What are MPAs used for and do they work?

Marine protected areas are an effective management tool to control extractive activity and increase fish stocks in designated areas, although some nations still allow extractive activity to occur in their MPAs. Marine protected areas banning all extractive activity (classified as ‘no-take’ marine reserves with full IUCN Category IA protection) have been very successful.

Marine protected areas have been scientifically proven to significantly increase the biomass, density, body size, abundance and biodiversity of marine species within their boundaries. Larger, older fish produce more offspring than smaller, younger fish (PISCO 2007).

Increased reproduction within MPAs leads to ‘spillover’ of adult and juvenile fish beyond the non-discrete boundaries of the MPA, leading to re-population of over-fished areas. MPAs encourage growth and recovery of exploited fish stocks, enabling populations of overfished species to be replenished naturally (PISCO 2007).

A recent study identified that establishment of marine protected areas with strict (full IUCN Category IA) protection in specific locations would conserve more than 80% of the habitat for endangered marine species, boost fish production and increase catches by 8,000,000 metric tons (Sala et al. 2021).

Most priority locations are within Exclusive Economic Zones (EEZs) so are more easily governed, with remaining locations in high seas governed by international law. The study quantified bottom trawling as being responsible for releasing one gigaton of CO2 into the ocean every year, equivalent to the aviation industry’s annual CO2 emissions.

Important Marine Mammal Areas (IMMAs)

An example of a special zone of protection is the designation and establishment of Important Marine Mammal Areas or IMMAs designed to protect cetaceans and improve conservation status of vulnerable or distinctive species or populations. Important Marine Mammal Areas (IMMAs) are “discrete portions of habitat, important to marine mammal species, that have the potential to be delineated and managed for conservation” (MMPATF 2020).

The Marine Mammal Protected Areas Task Force (MMPATF) has developed a set of 8 criteria, divided into four main categories, that are used to assess prospective Important Marine Mammal Areas (IMMAs) to qualify for IMMA status.

Of particular importance is Criterion C – Key Life Cycle Activities, divided into 3 sub-criteria – C1 Reproductive Areas (cetacean breeding grounds), C2 Feeding Areas (zones of high productivity) and C3 Migration Routes (the path many baleen whales take to get from their feeding grounds to their breeding grounds, where they give birth and nurse their young).

Of particular interest is where current and prospective Marine Protected Areas (MPAs) and Important Marine Mammal Areas (IMMAs) overlap, providing cetaceans with safe spaces within which to feed, breed and migrate.

© 2016 – 2021 Seafood Free September


Day, J., Dudley, N., Hockings, M., Holmes, G., Laffoley, D., Stolton, S., Wells, S. and Wenzel, L. (eds.) (2019). Guidelines for applying the IUCN protected area management categories to marine protected areas. Second edition. Gland. Switzerland: IUCN.

Great Barrier Reef Marine Park Authority (GBRMPA), 2021, Great Barrier Reef World Heritage Area,

International Union for Conservation of Nature (IUCN), 2021, Protected Area Categories,

Marine Mammal Protected Areas Task Force (MMPATF), 2020, IMMA Selection Criteria,

Marine Mammal Protected Areas Task Force (MMPATF), 2020, Important Marine Mammal Areas,

Marine Protection Atlas,, accessed 10.08.2021

Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO). 2007. The Science of Marine Reserves (2nd Edition, International Version). 22 pages.

Sala, E., Mayorga, J., Bradley, D. et al. Protecting the global ocean for biodiversity, food and climate. Nature 592, 397–402 (2021).