Because of their isolation, contrasting physiography and peripheral location towards the south-eastern edge of the vast Indo-Pacific region, the Pitcairn Islands are of great biogeographical interest. Since all the islands except Pitcairn have been uninhabited for hundreds of years, they provide a rare glimpse of insular marine ecosystems essentially untouched by human activities.

The Pitcairn Islands are separated from the nearest continental landmasses of New Zealand and South America by a distance of more than 4500 km. Their nearest neighbour, Temoe Atoll in the Gambier Islands, is located about 390 km to the west, whereas Easter Island lies 1900 km to the south-east.

Compared to other Polynesian archipelagos situated further to the west, the Pitcairn Islands have an impoverished fish fauna primarily due to their isolation, their more southerly location, their small size, and their lack of certain habitats such as estuaries, mangroves, and sea grass beds.

Including offshore pelagics, the total fish fauna of the Pitcairn Group is composed of 380 species in 209 genera and 76 families. Thirty of the fish species presented in this book are offshore pelagics and about thirteen are identified to genetic level only.

Pitcairn Island is the only inhabited island in the group and most of the islanders are descendants of the Bounty mutineers and their Polynesian followers who settled down on the island in 1790. Since 1887 the majority of the Pitcairners are members of the Seventh day Adventist Church.

The largest island in the Pitcairn Group is Henderson Island which is of outstanding scientific value. Being the world´s best example of an uninhabited elevated coral atoll ecosystem, Henderson Island gained World Heritage Site status in 1993. It is home to two endemic fish species, four unique endemic land birds and a global stronghold of oceanic gadfly petrels. Henderson Island also hold nine endemic plant species, eight endemic snail species, dozens of unique invertebrates and a crucial nesting habitat for the endangered Green turtle.