Are trout alien?

Posted on 20 September 2011

The question I’m about to ask was raised by a trout. A beautiful, silvery, yellow-brown one with red speckles and sleek as a rocket. The fish was perfect in every way except in its miscalculation and, evidently, its existence in that stream.

The miscalculation was to not notice that the delectable insect it successfully snared had a line attached that ran up through the eyes of my bent rod and around the reel in my hand.

Its existence there wasn’t a miscalculation but also, evidently, a problem – though no fault of its own. It had to do with a farmer named John Clive Parker who, in 1890, imported the eggs of its ancestors from Scotland and poured what he’d hatched into the Mooi River in KwaZulu-Natal.

The question it raised, as I held it in the moving water before letting it go, was to ask by what process of nature or decision by humans was it both alien and invasive?

And why were, say, some small creatures blown off the mainland clinging to a pile of floating debris not aliens on the island upon which they luckily landed? Nor the 57 species now found on the island of Surtsey near Iceland which appeared out of the sea in 1963 as a bubble of smoking lava devoid of life.

The South African Biodiversity Act of 2004 defines an alien species as “˜an indigenous species translocated “¦ to a place outside its natural distribution range in nature, but not an indigenous species that has extended its distribution range by natural means of migration or dispersal without human intervention.’

So to ask the question in another way: why are species considered alien only if they’re introduced by humans? Because what this implies is that we’re the ultimate terrestrial aliens and somehow beyond nature. I must confess there are times, particularly in shopping malls, when this thought occurs to me.

But the truth is we’re the noble descendents of the ratlike mammals that emerged out of the leaf litter following the cataclysmic asteroid event that wiped out the dinosaurs. Aren’t we part of the natural process? Wasn’t the asteroid?

I asked University of Cape Town zoologist Mike Picker, who recently completed and launched a book on alien and invasive animals with marine specialist Charles Griffiths.

“˜The asteroid was natural in that it came from the sky and was part of the solar system,’ he said. “˜But it was unnatural in that it was a very rare, once-off event. Not part of the normal processing of ecosystems. And it wrought massive changes. The impact of humans is rather like that asteroid – the pace of change is too fast for natural systems to stabilise around it. We’re fast-forwarding species range extension. I call it the Mac- Donaldisation of the global biota.’

It’s a very apt term, because much of what we’ve spread around is food. Where would we be without alien cows, sheep, pigs, potatoes, tomatoes, maize and almost the entire contents of a supermarket?

But let’s get back to trout. Duncan Brown is Dean of the Arts Faculty at the University of the Western Cape and likes to fish. He’s well aware that trout are alien, but he’s working on a book which, from the chapter I’ve read, will be a lyrical defence of fly-fishing. Its heading throws down the gauntlet: Are trout South African?

He doesn’t sidestep the argument that trout have caused ecological damage, nor that the colonists who imported them were part of “˜a grunting, lowing, neighing, crowing, chirping, snarling, buzzing, self-replicating and world-altering avalanche.’ But, with an ear to the quiet pleasure of a mountain stream, he asks, how far back do we turn the clock of alien definition?

Trout have been in Southern Africa for well over 100 years and are part of our everyday register of South Africanness, like mealies, bushpigs and pumpkins. More has been written about them than about any other animal in the world, except human beings themselves. There are more than 82 book-length texts on trout and fly-fishing in South Africa alone. A huge industry and even some towns depend on their presence.

Plant and animal species move not only through direct human intervention such as transportation, stocking or planting, he writes, but through habitat and climate change, which complicates simple arguments about indigeneity, endemicity and the right to belong. And, anyway, after 100 years, whatever damage they did has long since been done.

So Brown suggests a different take on trout. Manage them, he says, make sure they don’t invade the wrong streams, agree they’re scientifically alien but declare them culturally endemic. Along with oak trees, vineyards and Nguni cattle.

Of course, the worst aliens of all are us. But when we deport ourselves from these shores in the name of conservation, let’s leave the guy with the fly rod. Because what he does isn’t really about catching fish:

“˜To say that my identity is constituted at some fundamental level by being a fly-fisher,’ writes Brown, “˜is to say that I make time for beautiful places; that I am blessed by encounters with otters, dabchicks, fish eagles, malachite kingfishers as much as with people; that the world I see in two-dimensions must be imagined, and can only be imagined – rarely seen – in three; that I value solitude as well as quiet company; that I am frequently humbled by failure; that I know the places I love intimately, in all their moods; that there are trout which I know individually from their lies in the river; that with rod in hand I must modify my behaviour to encounter another species; that I am haunted by waters.’

He’s an appreciative asteroid.

Further reading:

Alien and Invasive Animals – a South African Perspective by Mike Picker and Charles Griffith went on sale in September (Struik Nature, R220).

Photograph and watercolour: Tom Sutcliffe, www.tomsutcliffe.co.za.






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