Is eating farmed salmon worth snuffing out 40m years of Tasmanian evolution?

The Guardian

06-04-2025

Australia is justly famous as a place where ancient species, long extinct elsewhere, live on. After aeons of adversity, Australia's living fossils often survive only in protected habitats: the Wollemi, Huon and King Billy pines, the Queensland lungfish and even the Tasmanian devil (which thrived on the mainland at the same time as the Egyptians were building the pyramids) are good examples. Such species are a source of wonder for anyone interested in the living world and they should serve as a source of hope that, given half a chance, even ancient, slow-changing species can survive periods of dramatic climate change.
Australia's largest repository of living fossils is arguably the cool, shallow marine waters off its southern coastline. Despite that fact that most of us enjoy a swim, snorkel or walk on the beach, the biological importance of our shallow temperate seas is almost entirely unrecognised.
In 1996 Tasmania's spotted handfish became the first marine fish to be listed as critically endangered by the International Union for Conservation of Nature. Found only around the Derwent River estuary, this 10cm-long Tasmanian has a cute, froggy face and hand-like fins, which it uses to 'walk' across the sea floor.
There are only 14 species of handfish, and all are restricted to the cool waters off southern Australia. Most have limited distributions, several are endangered and a few are known from just a single example. But what is truly surprising about handfish is that they were once widespread. A 50m-year-old fossil was unearthed in the Italian alps. So, like the platypus and Huon pine, handfish are relics, clinging precariously to life in Australia's cool southern waters.
The Maugean skate, also known as the 'thylacine of the sea', has become famous because it is endangered by salmon farming. It is also a living fossil, found only in the tannin-rich waters of Macquarie Harbour on Tasmania's west coast. The Maugean skate's relatives inhabit shallow marine waters around New Zealand and Patagonia, indicating that the species is a relic from the time, about 40m years ago, when Australia, Antarctica and South America were joined together to form Gondwana. Its predicament is forcing ordinary Australians to ask whether it's right to snuff out 40m years of evolution for a salmon bagel.
The bell clapper shell, found only in the shallow waters off Australia's south-west, is a third and most surprising relic. These long and narrow chalky white shells, shaped like the clapper of a bell, remain common enough that you have a fair chance of finding a sea-washed example on a beach walk anywhere between Perth and Esperance. Yet it is a living fossil with a truly exotic history. When workers were constructing the sewers of Paris in the 19th century, they often came across fossil bell clapper shells, some of which were up to a metre long. Right across the world, from Europe to eastern Australia, bell clapper fossils abound. Yet only in Western Australia's south-west can living examples still be seen.
Handfish, Maugean skates and bell clapper shells are just three charismatic species among a plethora of smaller and less spectacular marine species that have found refuge in the cool waters off southern Australia. Today the great juggernaut of climate breakdown threatens to extinguish their entire habitat. The heating caused by our emissions of greenhouse gases is not distributed evenly. The oceans are absorbing 90% of the heat trapped by the greenhouse gases, and the high latitudes are warming faster than areas closer to the equator.
Catastrophic changes are unfolding. Giant kelp once abounded in the shallows off eastern Tasmania. So great is the biodiversity found in groves of giant kelp that Charles Darwin called them the rainforests of the sea. Due to warming waters, in most places it's nothing but a memory. When the kelp vanishes, so does the biodiversity. Problems of simple warming are compounded by the migration of the long-spined sea urchin, which is spreading southwards as waters warm.
Without the strongest efforts to eliminate greenhouse gases, it can't be long before the first of southern Australia's marine living fossils wink out.
The survival of Australia's living fossils is a source of wonder and hope for me. The fact that platypus, which are little changed for 100m years, continue to survive in creeks and rivers near the largest Australian metropolises helps calm my worst fears about our future. And, while I may never see one in the wild, knowing that spotted handfish continue to walk the bay floor near the Hobart casino brings joy to my soul.
I continue to believe that once Australians realise what is at stake, they will act to protect our extraordinary biodiversity. There is no doubt that good climate policy is facing a Trumpian apocalypse. Yet, like our living fossils, some bold initiatives survive, among them Andrew Forrest's 'real zero' target by 2030 for his iron ore mines. If an energy-hungry iron ore miner operating in a remote corner of Australia can abolish all use of fossil fuels in the next five years, why can't we all?
Prof Tim Flannery is one of Australia's foremost climate change experts, an internationally recognised scientist, explorer and conservationist. He was named Australian of the Year in 2007 and is chief councillor of the Climate Council. He is also is a board member of Minderoo Foundation, Andrew Forrest's philanthropic vehicle