In this blogging series by Chris Firth, follow the life of a salmon smolt as it travels from the River Don’s headwaters to the low, meandering reaches of the river. Learn which fish species inhabit the three different reaches of the Don and pick up some of Chris’s expert identification tips along the way…
Crystal clear water tumbles, sparkling over a rocky riverbed under the warmth of the sinking sun. The upper reaches of rivers are generally unaffected by pollution, litter and development, offering us the opportunity to enjoy and experience a natural river environment. What could be more pleasant and relaxing than sitting on the banks of the river on a balmy summers evening watching fish rising, taking flies from the surface. This area of river could justifiably be described as its jewel in the crown.
Many centuries ago this headwaters, in the months of November and December, would have been a hive of activity. Hundreds of salmon, fresh from the sea, would have battled each other for a prime section of gravel in which to deposit their eggs.
Today this part of the Don is the preserve of the brown trout, a smaller but no less interesting cousin of the salmon. Apart from those occasions when we see the trout rise to the surface to take a fly, the life of these fish is largely hidden to us. What a shock we would get if we were able to submerge and witness the underwater commotion that is constantly taking place. This really is a hierarchical environment with fish constantly battling to protect their piece of feeding space. It may appear to us that there are only one or two fish when in reality there could be twenty or thirty in just five or six metres of river bed.
Brown trout lay their eggs at the same time of year as salmon and, for the first year and a half, the juveniles of both are difficult to identify from one another. At between 18 months and 2 years the young salmon begin to change significantly. The fish begin to assume a much more streamlined physique, their colour begins to change and they assume the same silver colouration of their parents. At this stage they are known as Smolts and are preparing themselves to journey down the river and out to sea.
The demise of the Don’s salmon population more than 200 years ago was brought about by the development of industry, in particular the construction of weirs, which obstructed the upstream passage of the fish. Over the last ten years amazing progress has been made in providing facilities to allow salmon to once again fulfil their desire to reproduce in the Don. Fish can now reach Sheffield and plans are in place to open up the river right up to those crystal clear sparking waters at the head of the river.
Between there and the sea the Don goes through many habitat changes from tumbling rocky fast flowing conditions to deep sluggish sections where the river resembles a long slowly moving pond rather than a river. Within these varied conditions a fascinating range of fish species exist. Over the next few weeks we will follow the experiences of a smolt on his downstream journey to the sea. Lets call him Salmo. Salmo will face many threats as he descends the river, from giant predatory fish to conditions where he struggles to breathe. Will our smolt make it to the sea and become a magnificent silver fish, capable of swimming against the fastest of flows? Will he return to those sparkling upstream reaches to mate, ensuring that new generations of salmon are there for people to wonder at?
Make sure to follow the smolt’s journey next week in part 2 of the Salmon’s Tale series, written by DCRT Trustee, Chris Firth.