Nutrient Restoration Trial Dee District Salmon Fishery Board
In the past, the decaying carcasses of 100’s of adult salmon would fertilise the stream and create an environment which boosted the growth of young fish. Streams that lack dead adult salmon have fewer insects (less ‘fish food’), so that the surviving fish fry are smaller and from fewer parents.
The Dee District Salmon Fishery Board plan is to use the lower legs of culled deer to replace the nutrients from the dead salmon that used to enrich the river. The legs, which are usually discarded, are a readily available, no cost, sustainable resource. They are pinned in bundles to the river bed.
They are also placing bundles of salmon food pellets at four sites, in quantities which replicate a salmon carcass. By comparing the effects on insect life, aquatic life and juvenile salmon numbers at the different sites we will discover the correct volume of deer legs to use in the years ahead. They will be monitoring the effect of this on algae, insects and aquatic life and of course juvenile salmon over the next 3 years. Invertebrate sampling will be carried out by the James Hutton Institute from June and fish sampling will be carried out in late summer.
Their aim is to send as many fit and healthy smolts to sea as possible. By kick-starting the cycle in the upper catchment, in the hope that the salmon and mother nature will do the rest.