Endemic
A species that lives in one region and nowhere else on earth - in this catalogue, one found in the Red Sea alone.
An endemic species is one that is native to a single geographic area and found nowhere else - often a single sea, lake or island group. Endemics have adapted to the particular conditions of that place, and cannot simply be found somewhere else if it changes.
The Red Sea is unusually rich in them. It is effectively a long, hot, salty dead end, connected to the Indian Ocean through one narrow strait, and repeatedly cut off from it during the ice ages when sea level dropped. Populations trapped inside diverged from their Indo-Pacific relatives, and a large share of the reef fish here - by some counts around a seventh of them - now occur in this sea and nowhere else.
That is also what makes them fragile. A species with one home has nowhere to retreat to, so habitat loss, warming water and overfishing weigh more heavily on an endemic than on a wide-ranging animal that happens to live here too. Cards marked as endemic in this catalogue carry that flag for exactly this reason.
Found in48
