It would seem that small fish see little threat posed by a pair of green rubber-clad feet and legs moving slowly, but purposefully, through their world. As I waded thigh-deep along the Sea Cut, shoals of minnows and fry moved only reluctantly away from me, coming within inches of my legs if I stood still for a couple of minutes. Even spiny loaches shot off to hide in the silt and stones only when they were in imminent danger of me stepping on them.

The Sea Cut is an artificial watercourse, dug out in 1804, linking the river Derwent to the sea. Beginning near Cockran Foot, in the valleys of the North Yorkshire Moors, it runs in a series of straight lengths to Scalby, where it tumbles over a series of weirs, then snakes out to the coast at Scalby New Rocks. Its course is roughly that of the pre-Ice Age river. It takes excess, rain-swollen flows off the Derwent and diverts them from flooding the villages of East and West Ayton.

A look on the Ordnance Survey map shows how the river reduces drastically in width immediately past the cut. Because of its flood alleviation purposes, the Environment Agency manages the banks. Few trees reach any size and the bank is lined with regular, thin stumps of alder. They do have a happy knack of sending up shoots to create small bushes though.

Below Newby Bridge, a series of weirs are each followed by deep pools, in which trout rise regularly for the floating flies.

The banks are wooded, or, where open, smothered in forget-me-not, dropwort and butterbur. A group of young boys attempted a spot of fishing, using bread on a hand-held line.

Boredom quickly set in, and by the time I had completed my survey, they had given up. They watched dozens of minnows attack lumps of sunken bread and spun yarns to each other of the huge fish they would have caught but for bad luck. They even try a tall tale on me as I amble past.

"Hey mister," one called. "We got a six-pound trout out of that pool." Oh yeah?