Farewell smooth handfish: What can we learn from the world’s first marine fish extinction?

PhysOrg

Earlier this month, a group of Australian scientists confirmed a depressing landmark for our blue planet: The first marine fish of modern times has been declared extinct on the IUCN RedList. The smooth handfish (Sympterichthys unipennis) was one of 14 (now 13) species of handfish, beautifully patterned creatures with a distinctly “missing link” look about them. Residing only in south-eastern Australian waters, these striking animals are bottom-dwellers that use their highly modified pectoral fins to “walk” along the seabed.

Smooth handfish were once so common in south-eastern Australia that it was one of the first species collected in an early scientific exploration of the country in the early 1800s by French zoologist François Péron. The species is now only known from the specimen collected in that expedition; during extensive in-water surveys of the species’ limited range since 2000, divers found no smooth handfish individuals, declaring it extinct.

Humans have hunted other types of marine animals to extinction before (for example, the Caribbean monk seal, hunted for oil and declared extinct in 1952). Other populations have been depleted to such an extent that we can no longer fish them (such as Canada’s Atlantic cod, which collapsed in 1992). But a marine fish species has never previously been recognised as extinct in the modern era. Given the way many marine fish breed (through sending their larvae into the water column, where they may disperse across great distances) and how variably human pressures can affect them, confirming that a marine fish species is extinct is notoriously difficult. Handfish are unusual fish in that they don’t have a midwater stage for their larvae. Instead, they give birth to fully formed juveniles directly on to the seabed. This means they only live in a handful of highly specialised areas and are therefore highly vulnerable to being fished or having the habitat they breed on disturbed. The story of the smooth handfish should stop us in our tracks and make us think long and hard about what price we’re willing to pay for our seafood, about what lies behind the notion of “sustainable” fisheries.

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