The conservation status and factors threatening fishes worldwide are r
eviewed in order to introduce a series of one-page articles on 'Threat
ened fishes of the world', and to encourage the incorporation of infor
mation on threatened fishes into international conservation programmes
. Information on fish extinction and threat rates are compared with th
ose of other animal groups, and the unique characteristics of fish con
servation problems are highlighted. At present 979 species of fishes a
re listed as threatened in the IUCN Red List and at least 36 species a
nd three subspecies are listed as recently extinct. It is argued that
these figures are probably gross underestimates and that they may misl
ead conservation authorities and resource users about the seriousness
of the situation. Freshwater fishes may be the most threatened group o
f vertebrates after the Amphibia. `Urgent action is required to save m
any narrowly endemic, stenotopic species from extinction, especially i
n Africa, Asia and South America. The conservation of common species t
hat drive essential ecological processes is also important. Anthropoge
nic pressures, especially habitat degradation, the introduction of inv
asive species and pollution, on inland and coastal waters are particul
arly severe and many major fish communities are threatened with elimin
ation throughout the world. The conservation of marine fishes is compl
icated by the fact that it is difficult to ascertain their rarity. The
importance of the retention of genetic variation is highlighted, and
both orthodox and innovative conservation measures are encouraged. Fur
ther research on minimum viable populations, genetics, and the factors
that cause fishes to become vulnerable to extinction, is urgently req
uired.