Indo-Pacific

The Indo-Pacific is a vast biogeographic region of Earth. It includes the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas that connect them. This region is very important in fields like marine biology and ichthyology, because many marine habitats are connected from Madagascar to Japan and Oceania.

As a marine realm, the Indo-Pacific has an exceptionally high species richness. The area's heart, known as the Coral Triangle, holds the world's highest number of species. The region includes over 3,000 species of fish and around 500 species of reef building corals.

Area covered by the Indo-Pacific biogeographic region

The term "Indo-Pacific" first appeared in studies of oceanography and geopolitics. Since the late 2010s, it has been used more in geopolitical discussions. Some see it as a replacement for the older "Asia-Pacific" idea. In geopolitics, the Indo-Pacific often relates to groups like the Quadrilateral Security Dialogue, or "Quad," which includes Australia, Japan, India, and the United States.

In its widest sense, the Indo-Pacific covers all nations and islands around the Indian Ocean or the Pacific Ocean. This includes countries such as India, South Africa, Indonesia, the Philippines, Taiwan, China, Korea, Japan, Russia, Australia, and many Pacific Islands. The ASEAN countries are considered to be at the center of the political Indo-Pacific.

Subdivisions

The WWF and Nature Conservancy divide the Indo-Pacific into three main areas, called realms. These realms are further split into smaller regions and areas known as ecoregions. Scientists have used different ways to divide the Indo-Pacific, but all methods show that this area is very rich in marine life.

The Central Indo-Pacific includes seas and straits connecting the Indian and Pacific Oceans. This area has the most marine diversity, especially in the Coral Triangle, where most of the world’s coral species live. The Eastern Indo-Pacific surrounds volcanic islands in the central Pacific, stretching from the Marshall Islands to as far as the west coast of Chile. The Western Indo-Pacific covers the western part of the Indian Ocean, including areas near Africa, the Red Sea, and many island groups.

Biogeographic regionalizations that were tested using model selection with analysis of molecular variance (AMOVA) by Crandall et al. 2019. Colours represent different regions within a scheme.

Main article: Central Indo-Pacific

Main article: Eastern Indo-Pacific

Main article: Western Indo-Pacific

Ecology

Some seashore and coastal plants grow all around the Indo-Pacific region. Trees like Pisonia grandis, Calophyllum inophyllum, Heliotropium arboreum, Pandanus tectorius, Cordia subcordata, and Guettarda speciosa, as well as shrubs such as Scaevola taccada, Suriana maritima, and Pemphis acidula, are common there. These plants are specially adapted to grow on coral sand and have seeds that can float in salt water, sometimes carried by birds.

Important trees like coconut (Coco nucifera), candlenut (Aleurites moluccanus), and Morinda citrifolia started in the Central Indo-Pacific and were spread across the region by people who lived there long ago.

Economic region

Geopolitical context

Historical precedent for the Indo-Pacific as a politically contested space comes from ancient times; in the European colonial era, commercial interests led to conquest by powers such as the Dutch and British East India Companies throughout the region.

The German geopolitician Karl Haushofer first used "Indo-Pacific" in the 1920s in multiple works on geography and geopolitics. Haushofer legitimated the integration of the two oceans by evidence in marine biology, oceanography, ethnography, and historical philology. He envisioned an "Indo-Pacific" comprising anticolonial forces in India and China, as Germany's ally against the maritime domination of Britain, the United States, and Western Europe.

Since 2011, the term "Indo-Pacific" is being used increasingly in geopolitical discourse. In 2013, the United States Department of State published a document formalizing the concept of a "Free and Open Indo-Pacific", to be sustained among members of "the Quad", a partnership of four Indo-Pacific democracies led by the United States, in concert with Australia, India, and Japan. "Indo-Pacific" has also featured prominently in top-level U.S. strategic documents. According to Felix Heiduk and Gudrun Wacker at the German Institute for International and Security Affairs, the concept of a "Free and Open Indo-Pacific" is aimed at containing China.

The term's profile was raised when it found mention in the joint statement issued by the Indian Prime Minister Narendra Modi and United States President Donald Trump after the former's state visit to the White House on 26 June 2017. Several state actors have published Indo-Pacific strategies, including the European Union (EU) in September 2021. In February 2022, the U.S. government released its official Indo-Pacific strategy, while in November of that year, the Canadian government released its own Indo-Pacific strategy. Canada have been described as walking a "diplomatic tightrope" in the Indo-Pacific, since they have attempted to align themselves with both China and U.S. allies like Japan.

Pacific Island country leaders have prioritized terms such as "Blue Pacific" and "Blue Continent" over Indo-Pacific, which is seen as potentially marginalizing them. The "Blue Pacific" identity was officially endorsed at the 48th Pacific Islands Forum meeting in Apia, Samoa, in September 2017. By 2019, the language among leaders shifted toward "Blue Pacific Continent". Australia and New Zealand, the two largest countries in the PIF, have engaged with the Blue Pacific Continent concept, while still using Indo-Pacific frameworks for broader regional contexts beyond the South Pacific area. Non-PIF members such as Japan, the United Kingdom and the United States have also engaged with the concept. German political scientist Patrick Köllner wrote in 2021 that New Zealand only views itself as being a regional power in the South Pacific, while Australia views itself as both a regional power in the South Pacific and a middle power in the Indo-Pacific.

The Indo-Pacific concept is yet not widely acknowledged amongst the governments of Latin American countries or Middle Eastern countries, countries which themselves are included under maximalist frameworks. As of 2023, no Middle Eastern country in the Gulf region had issued any official Indo-Pacific policy, with few leaders using the concept in public remarks. Much of Chile's Indo-Pacific strategy is expressed through the South Pacific Defense Ministers' Meeting (SPDMM), which it annually holds with officials from other countries bordering the South Pacific, including Australia, Fiji, New Zealand, Papua New Guinea, Tonga and France (who are considered a South Pacific country due to their various South Pacific territories).

Others have criticized the term for being overly broad, since under a maximalist definition, it encompasses every country with a Pacific or Indian Ocean coastline which accounts for 74 of all 194 independent countries, 65% of earth's total surface and a population of nearly 6 billion (three quarters of earth's total population). The maximalist definition is used by Indian Prime Minister Modi, who in 2018 defined the Indo-Pacific as encompassing any country with a Pacific or Indian Ocean coastline, including those in the Middle East, who are often treated as a separate geopolitical zone. On the other hand, the governments of the United States and Australia have defined anything west of Pakistan as not being part of the Indo-Pacific. They also define the United States as being the only country in the Americas belonging to the Indo-Pacific regional framework. Some wider definitions which include East Africa and the Middle East still do not include any of the countries of the Western Americas, instead ending the region at the Pacific Islands. The French government's official definition includes all their Pacific and Indian Ocean territories, ranging from the archipelago of Mayotte, which is close to the coast of East Africa, to the Pacific atoll of Clipperton Island, which is 1,100 kilometers from Mexico. Their definition encompasses mainland East Africa but not the mainland Western Americas. Their definition also does not include Russia. The Canadian government's official definition defines the Indo-Pacific as ranging from South Asia to the Pacific Islands, and encompasses 40 countries, excluding all countries from East Africa, the Middle East and the Western Americas, as well as Russia.