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Being prepared could save your fishery this summer!
It was an early start for Environment
Agency – Great Ouse and Fenland
Fisheries Teamtoday, dealing with an
ongoing incident at Swangey Lakes,
nr #Thetford. Our #24/7 on call Fisheries Duty Officer had been alerted by
the #fishery owner the previous night
to a sudden loss of colour and low dissolved oxygen levels in two lakes.
Fish were on the surface gasping, the
lake had gone completely clear and a
huge daphnia bloom was present (see
the amazing clip in the comments
below) – These are the ‘tell-tale’ signs
of an algae crash – completely natural
events, and they can be devastating
to a fishery.
Fearing the worst #TeamEA left the
office first thing with kit loaded and a
plan for whatever met us. We arrived
and took water samples – to assess
#algae levels, and checked
#waterquality too. It was obvious
algae had been an issue and the fish
were struggling, but that things were
slowly improving.
The fishery had been monitoring
oxygen levels with their own meter,
which allowed them to follow oxygen
fluctuations and predict the issue. No
fewer than 8 aeration units had been
deployed on the fishery; from venturi
units, paddle aerators and even two
tractor mounted hedge cutters – more
than we’ve seen at any other fishery;
and of course the fishery had called
Swangey Lakes had done
absolutely everything right, actioning
previous advice we had provided. In
the end we felt the issue was under
control, no fish had died and the fishery’s response had helped this idyllic
complex weather the worst of the
algae incident. We did however leave
two more aeration units and will
remain in contact with the fishery
until things are fully under control.
The lesson here is being prepared,
the fishery knew what to do, and
when – and had the kit to prevent
things from going #petetong.
As summer settles in and water
temperatures continue to rise the risk
to your fishery increases. If you do
nothing else with this post, remember
these tell-tale signs:
• Sudden change in water colour –
could signify a diatom or algae
bloom or a ‘crash’ – all can severely
impact oxygen levels
• Extremely low (2-20%) or extremely
high (120% plus) oxygen levels can
suggest an algae bloom may be
• Fish inactive in the margins – not
moving when approached
• Fish gasping at the surface, sometimes in large shoals
And finally, remember – if you see
fish in distress please call the Environment AgencyEmergency Hotline
number on 0800 80 70 60. Fishing
licence income directly funds the
fisheries work we do, and that
includes the work we deliver protecting fisheries during incidents. We’re
proud to offer this service, and very
often we really are the difference
between fish in distress and a fish kill.
There’s only one place you need to
buy your licence –
Follow this link
We will share some more detailed
advice for fisheries as we move
through the summer. n


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