The biodiversity of marine taxa is enormous. Of the 31 animal phyla on Earth, 15 are unique to the oceans. More than 250,000 marine species have been formally described, with hundreds of news species collected, examined and described each year. Priority marine clades were chosen for the GMSA project based on ecological and economic importance.
The first priority for all our regional assessments has been the marine bony fishes. Fishes are a vital component of local ecosystems, contributing to energy flow both up and down the food web. Forage fishes, such as small schooling anchovies, are the main pathway of energy transfer from the lower trophic levels (e.g., plankton) to the higher trophic levels (e.g., mammals, seabirds and predatory fish). Larger fishes provide the downwards path of energy transfer, contributing more nutrients to the base of the food web (e.g., seagrasses and algae) than any other source.
In addition to the important role fishes play in ecosystem health, they are also a key element in our economy and well-being. Almost every country exports fish. For some developing countries, fish products make up half the value of their traded commodities. With over half of the world relying on fish as some part of their diet, fish farms have become an important producer, supplying almost half of the world's supply. Tens of millions of people rely on catching or farming fish for their livelihoods.
We define marine fishes as those that spend all or a critical stage of their life cycle in marine waters. There are nearly 17,000 formally described marine fishes in the world and as of 2015, only 7,000 have been assessed using the IUCN Red List Categories and Criteria and published on the IUCN Red List website.