The End of the Reign of the King of Fish?
At the beginning of the month I attended the annual Welsh seminar of Salmon & Trout Conservation UK which was titled, ‘Can We Save the Atlantic Salmon?’
A rather doom laden title but the state of the Atlantic salmon is certainly hanging in the balance and this is coming off the back of the worst season (2018) on the Usk since records began, with just 130 salmon recorded as having being caught on rod and line. I know that we had just one small grilse caught here at Gliffaes. Add to these sad facts that electrofishing counts of juvenile stocks in the Usk catchment are also very low.
Some Good News
The seminar started with a talk and the showing of a short film by documentary maker, explorer and passionate fisherman, Will Millard. Will lives very close by one of the ‘industrial’ rivers of South Wales, The Taff. This river rises as two rivers in the Brecon Beacons; the Taf Fechan and the Taf Fawr before becoming one just north of Merthyr Tydfil and then joining the Severn Estuary at Cardiff. From the birth of the industrial revolution to the end of mining and heavy industry in the 1980s the River Taff was heavily polluted by all this activity.
Will explained that since the demise of the heavy industry in the last 30-40 years how the health of the river has improved and with the improvement in water quality so the have the salmon, trout and coarse fish populations begun to improve.
The New ‘heavy industry’.
While the health and vitality of the old industrial rivers continues to improve we on the Usk catchment can’t help but notice the steady decline of this once great river and we can point the finger at agriculture as the new ‘heavy industry’ that is effecting the river and all the streams in the Usk catchment. It has been the changes in farming practices along with climate change and water abstraction practices that have contributed to the decline in the health of the river.
The bugs tell the story
Invertebrates in the rivers, at the bottom of the food chain, are the indicators of ecological health of the river. The river needs to sustain diverse and numerous population of bugs in the water. As nymphs, insects are constantly exposed to the water, sometimes for years. A water sample would only give you river health information for a single point in time. Salmon and Trout Conservation UK have undertaken a river fly census on the Usk and other Welsh rivers.
What can be seen from reading the report is that the diversity of the insect population at the various sampling sites on the Usk ranges from 10-20 species, where a healthy count is deemed to be above 15 species.
The three main stresses on the insect population are:
~Phosphate run off (phosphate is found in agri-chemicals, manure and sewage).
~ Fine Soil run off causing siltation (phosphates stick to the soil particles and is washed into the rivers)
~Chemical run off (mainly nitrogen in fertiliser, which upsets the delicate chemical balance in the water)
All of these factors have increased due to changing and poor farming practices along the river. One only has to stand in the shallows and look at the stones on the river bed to see the effects of siltation. The stoney bed of the river (the habitat for the invertebrates) is now covered in sediment millimetres thick, smothering spawning redds and reducing the insect population. The phosphate and chemical run off causes algae to bloom in the water robbing it of its oxygen.
Carrot and Stick
Farmers living and working in sensitive areas of the catchment need to be wake up to the fact that the loss of soil from their land can not be replaced; no soil, no life. The Wye and Usk Foundation has a team of Farming Advisors tasked with assisting farmers on best practice and to help them see that changes will benefit them and the environment. Of course, more needs to be done on enforcement and on tying environmental improvements to farming subsidies. (Might some good come out of Brexit and the forging of our own agricultural policies?)
The other culprits
Blame for the decline in fish stocks can’t all be put on to agriculture there are many other factors at play. The river lives in a delicate balance and upsetting the water temperature, water levels and flow rates has great effects on all parts of the life cycle of the salmon. Global warming and climate change are having big impacts; if the water is just a couple of centigrade too warm salmon eggs are not viable, if water levels are too low there is less oxygen in the water and if abstraction is too severe after a spate then salmon waiting in the estuary to swim up on the flood water to spawn just won’t.
This is a huge topic and we have not even mentioned marine survival and this small piece is just trying to say what is happening in the river at the bottom of my garden. If you care about the survival of the salmon and everything else in the river you need to stay abreast of the issues and continue to support the conservation organisations and the Rivers Trusts who are working tirelessly to save our salmon.
I sent this piece as a draft to Simon Evans of The Wye and Usk Foundation and he added the following interesting remarks:
“Climate change/breakdown is affecting our rivers and the Usk salmon stocks in ways we didn’t consider. In the autumn of 2015 the water was 7 degrees above normal and crucially above the level that salmon could spawn successfully in much of the Usk catchment. More insidious was the effects of last summer, when the extended hot dry weather meant many lowland farmers were unable to set aside enough forage for their stock in the winter. This meant they grazed their stock for longer in the autumn reducing the opportunities for sheep to move from the uplands to the lowlands last winter. The upland farmers responded by planting increasing amounts of stubble turnips on ground prone to soil loss. This increased soil loss this winter and key Usk spawning streams like the Tarell and Honddu were especially badly affected.”