21-Aug-2006
- 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 Brampton. These
scale samples identified this salmon as a ‘1 sea
winter fish’, meaning it had been away at sea
for only one year.
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 Doncaster in 2002. This was
the first River Don rod and line caught salmon
for over 150 years.
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
Rotherham.
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
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 Doncaster
1856, also note that poaching of the small salmon
population in the headwater spawning areas to
be a major problem. Many were sent for sale to
Paris, where they received a premium price.
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 Doncaster. The number of
reports of salmon being spotted in the river by
anglers then began to grow.
Alexandra Wales
