Indo-Pacific

The Indo-Pacific is a huge area of Earth. It includes the warm waters of the Indian Ocean, the western and central Pacific Ocean, and the seas that connect them. This area is very important for studying sea life and fish because many sea homes are linked from Madagascar to Japan and Oceania.

As a home for sea animals, the Indo-Pacific has many different species. The center of this area, called the Coral Triangle, has the most species in the world. The region includes over 3,000 kinds of fish and about 500 kinds of reef building corals.

Area covered by the Indo-Pacific biogeographic region

The name "Indo-Pacific" started in studies of oceanography and world politics. Since the late 2010s, people use it more when talking about politics. Some think it replaces the older idea of the "Asia-Pacific". In politics, the Indo-Pacific often talks about groups like the Quadrilateral Security Dialogue, or "Quad." This group includes Australia, Japan, India, and the United States.

In the broadest sense, the Indo-Pacific includes all the lands and islands around the Indian Ocean or the Pacific Ocean. This includes places such as India, South Africa, Indonesia, the Philippines, Taiwan, China, Korea, Japan, Russia, Australia, and many Pacific Islands. The ASEAN countries are seen as the heart of the political Indo-Pacific.

Subdivisions

The WWF and Nature Conservancy split the Indo-Pacific into three main areas, called realms. These realms are divided into smaller regions and areas known as ecoregions. Scientists use different ways to split the Indo-Pacific, but all show that this area has a lot of 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 many of the world’s coral species live. The Eastern Indo-Pacific surrounds volcanic islands in the central Pacific, stretching from the Marshall Islands to 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

Many plants grow along the coasts and on the shores of the Indo-Pacific region. Trees such as Pisonia grandis, Calophyllum inophyllum, Heliotropium arboreum, Pandanus tectorius, Cordia subcordata, and Guettarda speciosa are common there. Shrubs like Scaevola taccada, Suriana maritima, and Pemphis acidula also grow in this area. These plants are special because they can grow on sand made from coral and their seeds can float in salty water. Sometimes birds carry these seeds to new places.

Important trees like coconut (Coco nucifera), candlenut (Aleurites moluccanus), and Morinda citrifolia began in the Central Indo-Pacific. People who lived there long ago helped spread these trees across the region.

Economic region

Geopolitical context

The term "Indo-Pacific" has been used for many years. It was first used in the 1920s by a German expert named Karl Haushofer. He studied geography and politics. He thought of the Indo-Pacific as a way to connect India and China.

Today, many countries use the term "Indo-Pacific" to talk about the area including the Indian Ocean and the Pacific Ocean. In 2013, the United States said it wanted a "Free and Open Indo-Pacific." This idea is supported by countries like the United States, Australia, India, and Japan.

Leaders from many countries have talked about the Indo-Pacific, including the European Union. Some leaders from Pacific Island countries prefer to use the term "Blue Pacific" instead, because they feel "Indo-Pacific" might ignore them.

Different countries have different ideas about what the Indo-Pacific includes. Some say it includes many countries around the Indian Ocean and Pacific Ocean. Others have smaller ideas about the area.