Meanwhile, a small-scale radio project has yielded fascinating information about how fish approach the main hydro dam at Kilmorack.Last summer 10 salmon were netted below the dam and fitted with radios. Three automatic listening stations monitored their movements: one as they approached from below, another as they entered the bottom chamber of the lift, and a third as they emerged from the top. Midwood points out, "It's tremendously difficult to find out what's actually happening". Although not many fish have been caught yet this spring, everyone agrees that there are more salmon in the river than at this time last year. Now the first of them should be coming back as two-sea-winter salmon."Should be" is the operative phrase As Mr.

In June 1992 he therefore arranged for over 100,000 fed fry (baby salmon) hatched from Beauly spawn to be planted in burns far up-river.In due course these fry grew into parr, and then into smolts. The bad point is that they retard the passage of fish upstream, even though they are fitted with lifts which allow salmon to go through.William Midwood, managing director of the new company, reasoned that the higher up the river a salmon is bred, the earlier it is likely to return from the sea, since it has farther to go to reach the breeding ground which instinct makes it seek out. Those which survived should have been washed downriver, over the falls and through the dams to the sea, during 1994. Any number of salmon can be caught in June, July and August - but might it be possible to re-build April and May?One fact of life on the Beauly, for good or ill, is the pair of hydro- electric dams built in the 1950s. Their good point, piscatorially speaking, is that they conserve vast quantities of water, some of which is constantly being let through, so that even in a drought the river has a good flow. Cynics may claim that part of the rise was due simply to more intensive fishing, but there is no question that the remedial measures have had a beneficial effect.A more subtle challenge was to recreate the spring run for which the river used to be famous.

For six centuries the river belonged to the Lovat family, but in May 1990 the fishing rights were bought by the newly-formed Beauly River Fishings Company, which began an ambitious programme of improvement. Part of this was the physical refurbishment of the waterway, and included the creation of new pools and the clearing of the burns in which salmon spawn. This certainly seemed to help, for the annual catch leapt up from a 10- year average of 678 to more than double. However carrying on in this way keeps us out of the pubs and off the streets for at least one day a week..."Oldland Mill can be visited tomorrow: details from Mr Annett on 01273 843573. Information on other mills (some 200) open for National Mills Day can be obtained from the organisers, the Wind and Watermills Section of the Society for the Protection of Ancient Buildings Telephone 0171- 377 1644 for details.. Is the great experiment working, or is it not? That is the question fly-fishermen are asking on the River Beauly, north of Inverness - for this is the first spring in which it should be possible to gauge the results of the imaginative re-stocking programme which was launched four years ago.