Last day electrofishing: the Inverton Burn

The Inverton Burn (a.k.a. Milton Burn, but there are enough of them on the Spey already) flows under the A9 opposite Kingussie. Few surveys on this burn had been completed so we set out on the last day of our planned electrofishing surveys to collect some data.  The first site was in the lower reaches a short distance downstream of the A9. The burn was wider than I expected but finding a suitable survey site was not easy. The burn consisted of long glide/pools with short riffles between. I like to select representative habitat so we picked the shortest glide and two riffles to survey.

Downstream view of the lower site. I thought it would be stuffed with salmon fry but it wasn't. Can't rmemebr the figures but there were about 15 fry and 8 salmon parr, couple trout fry, eels and lamprey.

Downstream view of the lower site. I thought the riffles would be stuffed with salmon fry but they weren’t. Can’t remember the figures but we found about 15 fry and 8 salmon parr, couple of trout fry, eels and lamprey.

With no previous data to compare we crossed the A9 and headed upstream. The middle site was classic salmon parr habitat; perfect size boulders with lots of voids between.

Perfect parr habitat in the middle site in the Inverton Burn.

Perfect parr habitat in the middle site in the Inverton Burn. We found plenty salmon parr here but only a few fry with two larger trout.

The third and upper site has previous. It had been surveyed before in 1994. We had photos and a good site description so it was easy to find the exact spot again. The 1994 site notes said “copious amounts of  weed”. That aspect hadn’t changed; there was an abundance of instream plants.

The site description was "downstream Wade's Bridge". The bridge was yet another testimony to a great engineer, the stone arch

The 1994 site description was “downstream of Wade’s Bridge”. The long lasting stone arch bridge was yet another testimony to the great engineer. The single alder was dropping quite a lot of leaves into the burn – good winter fodder for all sorts of aquatic critters.

In 1994 eight trout fry, five trout parr and a single salmon parr were found in a site 16m long. As well as weed cover, the cobbles and boulders were of an excellent size to provide small fish shelters, in fact the burn was very reminiscent of many I knew in Lewis; they were usually stuffed with salmon. The first sweep yielded a trout fry but the momentum wasn’t maintained and the catch was less than expected. We caught a few trout fry, one or two trout parr but we did catch a single salmon parr – some things never change. We also caught a first for all the team – several small pike.

The solitary salmon parr from the Wade's Bridge site and a couple trout fry.

The solitary salmon parr from the Wade’s Bridge site and a couple trout fry.

 

 quartet of pikelets bonnie wee fish they were. Lovely little strip below the eye.

A quartet of pikelets; bonnie wee fish they were. Each one had a lovely little bar below the eye. At 80-90mm they must be this years fish but we need to check the scales to confirm.

Downstream of Wade’s Bridge the burn flows through a reedy loch which is probably full of pike. There must be the odd salmon making it above the reedy lochan to spawn occasionally.

The three survey sites in the Inverton Burn were all very different. Where the habitat was good for salmon parr there were plenty but the low fry numbers suggest that not enough fish spawned there last winter. The burn above the lochan looked like excellent habitat but maybe the pressure from other fish species is limiting the salmon potential now. Up there the burn was 5m wide, a size normally suitable for salmon. It is interesting to consider whether the upper reaches of the Inverton Burn would have supported a better juvenile salmon population when the run of adult fish was larger? However in the early 90s the upper river catches were much higher than seen in recent years but there was still only the same single salmon parr found then??

We must go and walk the Inverton Burn this winter.

 

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