The dawn chorus of fish

Early morning on a canal can offer a surprising window into the hidden world of fish, says Fergus Collins

A shot of a canal and tow path with spring colour reflections in the canal.

July has the sadness of silence about it. Gone are the intense dawn choruses and daytime chatter of birds that have thrilled me since mid February. Wildflowers still delight and there are tremendous numbers of interesting insects to meet yet I can’t help feeling bereft.

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Then, during the super-hot days of mid July, I discovered a wildlife marvel that has helped take the birds’ place. I was blessed with a couple of midweek days off completely to myself. I still had the dog to look after but he was visibly wilting in the heat on walks so I got up extra early and took him out before the sun had assumed its full strength – about 7am.

We set off on a long, shady woodland path and then returned via the towpath of the Monmouthshire-Brecon canal. There was a lovely light and the temperature was stimulating rather than suffocating.

Normally the canal in summer is muddy brown as numerous narrowboat propellers stir up the mud. The Mon-Brec is not a deep canal so even small boats cause disturbance. But I was up before the boaters and, overnight, the silt had settled. The water was luminous and largely clear. And I could see huge numbers of fish where shafts of bright sun penetrated the depths.

It’s not rare for the canal water to be clear. In winter, you can see to the bottom with all the fallen leaves, branches and car tyres that one might expect. But in winter the fish vanish too– presumably to deeper, darker stretches. So this was a beautiful and unexpected scene: my own giant aquarium.

Most obvious were vast shoals of roach – glowing blue-green in the morning light as they flicked the water’s surface to pick off insects. Barrelling through the shoals were much larger fish with red spiky fins and striped backs. These were perch.

Female mallard duck -Anas platyrhynchos- feeding on the leaf of a White Water Lily -Nymphaea alba-, with Common Roaches -Rutilus rutilus- and Common Rudds -Scardinius erythrophthalmus- beolw, Lake Seeon, Seeon, Upper Bavaria, Bavaria, Germany
Shoals of roach at the water’s surface/Credit: Getty

I felt rather than heard a pulsing vibration behind me and, 200 yards away, the first boat of the day was approaching. I quickened my pace away from it and watched more watery wonders unfold. In the shallows, thousands upon thousands of fry flickered and danced – shooting away (and into the paths of hungry perch) as my shadow fell on them.

Some large, shadowy deep-keeled fish that I guessed were bream nosed along the canal bed; I wondered what they were finding to eat in the thick mud that they stirred up. A hundred yards or so later, I came to a line of moored boats and beneath one was the distinct slender torpedo of a small pike. Through binoculars, it looked a monster though was probably no more than a foot long.

Northern Pike, Esox lucius, Germany, Echinger Weiher Lake, Munich, Bavaria
A pike lurking in shallow water/Credit: Getty
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The boat eventually overtook me and the effect was as if someone has slid the etch-a-sketch eraser across the whole canal. Mushroom clouds of silt billowed in the boat’s gentle wake and the clear canal became a thick oxtail soup colour. The fish gone for another day.