Most recent fish extinction

The most recent fish to be declared extinct by the International Union for Conservation of Nature (IUCN) is the smooth handfish (Sympterichthys unipennis) in March 2020. Only a single photograph of this species is known to exist, of a specimen that was collected in shallow coastal waters off Australia by the French naturalist François Péron at some point between 1800 and 1804; not a single other smooth handfish has been documented since. This makes it the first marine bony fish to be deemed extinct in modern times. The main causes of its demise are assumed to be those that also threaten the 13 remaining members of the handfish family: pollution, habitat loss (partly caused by destructive fishing techniques) and predation by invasive species. Of the 13 extant handfish species, all of which are endemic to the shallow waters off Tasmania and mainland Australia, four are classed as Endangered, three as Critically Endangered and data is currently deficient to make an assessment on the other six.

Handfish are so-called for their prominent pectoral and pelvic fins, which they use to "walk" along the seafloor. They favour this form of locomotion because they lack a swim bladder, which aids buoyancy in most fish species.

The fate of other handfish also looks bleak. According to Jemina Stuart-Smith of the Institute for Marine and Antarctic Studies and manager of the Handfish Conservation Project, only four of the 13 species have been sighted in the last two decades.

The official demise of the smooth handfish swiftly follows in the wake of that of the Chinese paddlefish (Psephurus gladius), declared extinct in Jan 2020. This freshwater species had been categorized as Critically Endangered for a number of years, and had not been seen since 2003 in either the Yangtze River basin or the latter river's East China Sea estuary that constituted its only known habitat in recent times (historically it was also known from the Yellow River). Accordingly, in Jan 2020 this species was formally announced to be extinct by the Chinese Academy of Fishery Sciences and the IUCN, who consider that it likely disappeared sometime between 2005 and 2010, due to overfishing and habitat loss.