NATURE: A tale of twists and turns lost on Mayo’s Annies River

How could it be a full year ago that I was last here, peering over the parapet into the same glassy water, straining to see the silver flank and dark, broad tail of those same trout I hunted on the summer lake?
Last winter a dark wave had unfurled from the far bank, as if a stone had been hurled into the stream. Yet there was no splash, just a subtle shift of shadow into sunlight and that spreading, downstream ripple. A yard behind, a line of bubbles broke the surface with a barely audible sound – more a soothing ‘Hush’ than a hiss.
Beneath the bridge lies one of the few gravel patches to be found in the entire stream. More than a century of deepening and straightening has stripped Annies River of character, though not entirely. The natural stream/pool sequence might be no more, the nourishing flood spilling wide over low-lying land a thing of the past, but life enough remains to leave hope: hope that one day we will mend our ways and heal this broken land, that we can allow life to bloom in abundance, to flourish, as in the days before we brought the machine.
Just who’s idea had it been, this imagined improvement? How had such mean spirit been entertained by right-thinking men? The small ground gained by intensive drainage is of such poor quality the effort and expense must never have paid off, not then nor now.
Carra’s trout flood into the Annies River each autumn to spawn beneath this bridge, where a few shallow gravel mounds scarcely allow room to dig. Dig they do, and into the trench exposed by their labour precious eggs are poured. More work has them buried. Yet even as the spent hens drift slowly back to their lake, others arrive with an equal urge to spawn. And so previously laid eggs are exposed, tumbled in the current, washed to other gourmand fish that have gathered downstream, waiting for the feast.
So too the otter dines finely when able. For most of the year he must hunt the length of this water, venturing onto bog in search of frogs, along drains and into fields to find small mammals, to the riffling stream where crayfish and freshwater clams can be found, and as far as the lake, where he once found eels, to feed up on perch.
For now, he has a shoal of spawning trout at his disposal. Hunting has never been easier. Concentrated in this one spot, their minds are on the task at hand, and as the otter swoops among them they have nowhere to flee.
Others are also aware of their presence. Not this year, but previously, we found stout nylon lines attached to overhanging branches, armed with sharp hooks and earthworm baits. When trout spawned the length of the stream such tactics were haphazard and might or might not work. Now they rarely fail.
The otter has made his mark on the landscape. On the lake itself we have Otter Point, where rocks are covered in spraint to this day, and the nearby Otter Island, a favoured haunt for generations of these elusive animals.
Elusive, I say, but only if you don’t know where to find them. Yes, as with most of our wild things, they have become rather scarce. Yet they are also creatures of habit that follow traditional ways. Otter Point is still Otter Point and Otter Island remains a stopping-off spot for animals on their way from one arm of Lough Carra through the shallow Narrows and into that second spreading arm.
There is no shortage of perfect habitat here, nor any shortage of prey, for where Carra’s world-famous but diminishing trout population leave vacant territory, so other fish species take up the slack.
Perch reproduce rapidly, with a large female capable of producing upward of 200,000 eggs, roughly ten times the number produced by a trout of the same weight. Perch spawn in weedy areas all around the lake, rather than in the very few patches of gravel available to trout, and thus enjoy further advantage in being less visible to predators.
It is a wonder that the beleaguered trout of Lough Carra sustain themselves at all. Unless some kind of balance is restored this may not continue, for they are losing ground already.
Part-solutions are simple. Restore the spawning gravels. Let the trout that remain spread throughout the catchment and spawn. Why, we ask, is this a difficult thing?

Michael Kingdon, a naturalist and keen fisherman, lives on the shores of Mayo’s Lough Carra, the best example of a shallow marl lake in western Europe and therefore an SAC of enormous ecological and conservation importance.