The 24-rayed sunstar and the black-spotted damselfish are believed extinct, while the Galapagos penguin is within "a hair's breadth of annihilation," said a report in the journal Global Change Biology.
Another six species are possibly extinct while 36 species are classified as vulnerable, endangered or critically endangered, the International Union for the Conservation of Nature said.
Scientists blame rising water temperatures caused by global warming and over fishing and tourism, Sky News (Britain) reported Friday.
"If marine species are going extinct in one of the most famous and most cherished world heritage sites, what is happening in the rest of the world that has been so little studied," asked Scott Henderson, a marine researchers from Conservation International.
The Galapagos Islands are famed for the vast number of species studied by Charles Darwin, whose observations led to Darwin's theory of evolution by natural selection.
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