7-Jul-2006
- Yesterday (Thursday 6 July 2006) the Environment
Agency saved approximately 1,000 dying fish at
Briget’s Pool, Trent Vale.
We received a report from a
worried member of the public about fish in distress
at Briget’s Pool, which is controlled by Embrey’s
Fishing Club.
Environment Agency fisheries
staff attended the pool immediately and tested
the oxygen levels in the water. The results of
the tests showed that the level of oxygen in the
water was dangerously low, meaning that fish could
suffocate.
The pool is used to teach children
how to fish and is also used frequently by disabled
anglers.
Local residents watched as Fisheries
staff used specialist equipment to put oxygen
back into the water in the pond. The team used
hydrogen peroxide to bring oxygen levels in Briget’s
Pool back to safe levels for the fish and estimate
that 1,000 fish were saved.
Phil Wormald, the Fisheries,
Recreation and Biodiversity Team leader involved
in yesterdays rescue said; "Fish can easily
become distressed at this time of year because
of high water temperature and low oxygen levels.
Natural death of algae in the water and low pressure
during thunderstorms can also strip oxygen from
the water, causing fish to suffocate."
"Yesterday we managed to
save hundreds of fish by pumping oxygen back into
the pond. Lake owners can reduce the risk of summer
fish kills by reducing the number of fish in a
pool, providing deep water and shading with trees
and water lillies."
Notes to editors
Summer fish deaths are a seasonal
phenomenon caused by a specific combination of
weather conditions. Fish deaths can occur as a
result of lack of oxygen:
Hot weather increases water
temperature and warm water holds less oxygen than
cold
Sudden heavy rain or thunderstorms cause a sudden
influx of cold water. This takes algae down to
the bottom of the pond where it dies due to lack
of light and decomposes, causing a rapid drop
in oxygen levels in the water.
However, algae do not need to be present. The
same thing can happen when organic matter in the
water in stirred up by the heavy rain, stripping
oxygen out of the water.
It can happen very quickly, unexpectedly and often
at night because all water plants (such as algae)
use more oxygen at night.
Dead, dying or distressed fish in public rivers,
streams, lakes and ponds should be reported immediately
by calling 0800 80 70 60 (free 24 hour service).
What are algal blooms?
A combination of shallow water,
warm weather and high nutrient levels can often
cause algae (aquatic plants) to rapidly multiply
- turning the water a green colour and causing
massive fluctuations in oxygen levels. In these
conditions fish can become stressed and may eventually
suffocate. Normally the build up of nutrients
would be flushed out of the system with high winter
flows.
Holly Smith
