Some years back, returning to my childhood bush home after decades away, I found the house gone and the flourishing garden and surrounding woodland I once knew reduced to something like desert, spindly trees in a sea of weeds. I put it down to a drying climate.
Between where I had lived and and the newsprint mill nearby were bare patches of ground, the sites of other homes which in my time there had been filled with families, kids I played with down by the river. Mill management, I thought, must have wanted the whole place to themselves.
My brother lived in the family home for years after I’d left, studying botany and earning first-class honours before going to New Zealand to live. On a visit last week, he debunked my theory that climate was the main cause of our childhood home’s degraded environment, pointing out that Google Earth showed the damage was restricted to a semicircle radiating out from the riverside mill.
The culprit, he said, was noise from a bit of mill machinery installed in his last years there to strip bark from big logs. Ground vibration from the bark-stripper’s regular low-frequency thumps, besides forcing people out of their homes, impaired the ability of nearby plants and animals to live, grow and reproduce.
The Australian Academy of Science has found that noise affecting animal behaviour affects species and whole ecosystems. The impact is felt keenly in the sea, where thumping ship engines and booming seismic surveys affect life in the farthest reaches of the deep ocean.
Human industry sometimes calls itself environmentally friendly. But nothing we do is without some sort of environmental impact, and whether or not that impact is friendly depends entirely on perspective. When they first started up in Tasmania, marine salmon farms would generally have been considered friendly. But no more.
Noise is part of this, from marine engines, feeding processes and anti-seal cracker bombs, as is the feed and faeces that finds its way to the sea floor. But what turned up on D’Entrecasteaux Channel shores last week had nothing to do with noise, a little to do with fouling of the sea, a lot to do with climate change, and a great deal to do with politics, profit and self-interest.
It’s never easy to get information about a disaster of any kind, especially one that smells as badly as this. Thousands upon thousands of bits of pink flesh and odorous oily scum turned out to have come from a mass salmon mortality event in Huon Aquaculture pens in the Channel.
Working out what happened remains a work in progress. It appears that the fish died as a result of infection by a group of bacteria called Rickettsia-like organisms (RLOs), and that many carcasses broke up and drifted out of the open-net pens before washing up on nearby shores, along with oil ejected from the fish which collected sand to form fatty, foul-smelling balls.
The conditions in which the deaths occurred were anything but healthy for the salmon. Jellyfish expert Dr Lisa Gershwin says south-east Tasmanian waters over summer have seen three successive infestations of different organisms – a species of zooplankton called salp, the light-emitting plankton Noctiluca scintillans, and the common Moon jellyfish, Aurelia – adding up to an exceptional risk to fish health.
A critical factor is climate change, or more specifically ocean warming, bad news for Atlantic salmon because warm water carries less dissolved oxygen, increasing their susceptibility to disease. And stocking an average-sized salmon pen 70 or so metres across with around 50,000 fish signals an industry that puts profit ahead of animal health.
All this comes back to the failure of successive governments to understand that industry self-regulation cannot work because private interest will almost always trump prudence and caution. Business people who follow their conscience and behave responsibly – farming salmon on land while and reabsorbing its waste, for example – are doomed to be uncompetitive unless government enacts and enforces proper regulations.
Canada will end open-net marine salmon farming from 2029 because of its ecological impact. Here it is being shielded from fully independent regulation while both major parties shamefully attack those who stand up for the natural values that represent the world which made us – and whose loss is a signpost to where we may be headed.
In her debut novel The Clinking, launched in Hobart last week, Susie Greenhill writes of the grief felt by many Tasmanians at the loss of the nature that has shaped her life. Hers is a welcome new voice in this critically important space.