The Environment Agency has had further positive proof that salmon are beginning to return to the River Don after the fisheries survey team captured an 11lb salmon below Sprotborough Weir this month.
The salmon was captured in a routine fish survey and scales from the fish were then sent to our laboratory at
Despite several reported observations of salmon trying to ascend the river each Autumn during the last few years, this is the first specimen to be accurately recorded since a salmon was caught by a local angler in
This is major development in the recovery of the River Don and shows the improvements in water quality that have been made, despite the recent pollution incident on the river which killed thousands of fish.
The salmon also had a lot of erosion at the scale edge and to the fins, which indicates that it had been in the river for a while, probably trying to ascend the weir, well before the pollution incident.
Environment Agency fisheries technical specialist Neil Trudgill said: “This is positive news following the pollution incident in July, and the fact that this salmon survived the pollution bodes well for the more tolerant coarse fish species, indicating that many would have survived the incident.”
The low oxygen levels that cause many fish to die were a result of a period of dry weather and low river flow followed by an intense rainfall event, causing sewage from storm overflows to enter the river in Sheffield and
Environment Agency officers worked against the clock to save hundreds of coarse fish in the River Don, using the latest methods to help reoxygenate the river, whilst using large pumps to remove the sewage sludge.
Despite the improvements to water quality over the last few years, which has allowed the formation of viable coarse and trout fisheries, the weirs on the river still act as a major obstacle to some River Don fish populations.
There are approximately 30 weirs still present on the main river and of these, five (including Sprotborough) have been identified as major obstacles in preventing gravel spawning species such as barbel, chub and salmon from reaching the major spawning grounds around Rotherham and Sheffield.
Ends
Image enclosed: Ecological appraisal officer Daniel Smallwood with the salmon
Notes to editors:
History of salmon in the River Don:
Salmon numbers were extremely high in the River Don until the late 17th century, when several of the larger weir structures on the river, which were built to supply the water mill industry, were fitted with hecks, a type of salmon trap. Quantities caught were not recorded, but salmon was know to be readily available.
During the following 150 years conditions changed dramatically and by 1770 the number of water-powered operations had grown to 161. Any remaining self-sustaining salmon population was on its way out because of the barriers which stop the salmon from migrating.
All commercial interest in salmon on the Don finished by 1776, as the many barriers meant that few reached the spawning grounds.
Salmon survived longer in the lower tributaries, such as the Dearne, but other impacts such as navigation – resulting in the creation of locks and weirs downstream – took a heavy toll on numbers.
Historical notices of
Pollution of the Don system was so bad by the 1860s that it is unlikely that any spawning fish were returning to the Don by this time.
However, with vast improvements in water quality, the first sign of the return of the salmon on the Don was in 1996, when a kelt ( a spawned salmon) was found dead in the River Don just downstream of
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