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Knowle Angling Association was formed at the Knowle Hotel, (hence it's name), in 1923. We are a local, sociable and family friendly club. Since the club was formed we have had over 2000 members join us. At it's formation, KAA fished the river Chew exclusively. Since then the club has steadily grown, and, in addition to large stretches of the river Chew, has added the river Yeo, one stretch of the river Wellow, four well stocked trout lakes, and one coarse fishing lake for members to fish. So if you are looking for outstanding and affordable all year round trout fishing in and around the Chew Valley then come and join us.

We are proud of our efforts to maintain the stocks of Brown Trout in our rivers, and we source top quality Rainbow trout to stock our lakes. We take care of river management with regular bank clearing sessions. 
KAA has a proud history, and our articles and byelaws are designed to protect our fish and the environment. We continually look to the future, encouraging fly anglers of all abilities, ages and gender to join us.

Visit to Bristol Water Hatchery

The visit took place on Saturday 3rd December 2011 and lasted from 1030 to 1230, some 20 members were present.  We met at Woodford Lodge and sharing transport, due to limitations on parking, proceeded to the facility.

 The BW fish hatchery is situated at Ubley, in the Chew Valley, close to both Blagdon and the Chew Valley Lakes; it consists of several older buildings and some 20 concrete stew ponds.  Water is supplied to the facility by a number of sources e.g. the Chew Valley Lake, Blagdon or Cheddar Reservoir; each source differs in temperature, chemistry and clarity and requires the BW staff to carefully monitor and manage the environment for the fish.  To ensure the water is properly oxygenated air is constantly pumped into the stew ponds; the higher the water temperature, the lower the dissolved oxygen level.



Only Brown and Rainbow Trout are bread at the hatchery, the ratio is some 90% Rainbow to 10% Brown and a total quantity of 100, 000 to 120,000 fish are produced each year.  The bulk of the fish produced are either female or triploid.  A triploid is so called because its reproductive organs (gonads) are not present.  The techniques used to produce triploids include: subjecting the eggs to high pressure or heat. 


BW buys in many of the fish eggs from a facility on the Isle of Man; they also produce some of their own.  A small, artificial channel from Blagdon Lake enters the facility, cock and hen fish swim up this to breed and find themselves in the BW stew pond.  The fish are removed and checked to see if they are ready to spawn; if they are, the female is held over a dry container and the belly gently squeezed to evacuate the eggs.  The eggs are bright orange in colour and about a tenth of an inch in diameter; each female can yield a lot of eggs.  Two cock fish are then selected, two in case one is sterile, and carefully squeezed so that the milt (sperm) goes in with the eggs.  The eggs/sperm mix is carefully stirred and left for a short while, water is then added to the container and after a few minutes more, the eggs are carefully washed in running water.


After fertilisation the eggs are put into shallow perforated baskets in troughs of running water; the eggs need 360 degree days to hatch i.e. 36 days at 10 degrees, longer if the temperature is lower, less if the temperature is higher, 9 to 11 degrees is optimum.  The fry emerge from their eggs with a small yoke sack and are able to escape through the perforations in the baskets.  After about five days they absorb their egg sack and then they are removed from the troughs, placed in stew ponds and fed with a high protein food that resembles dust.



As the fish grow, they are progressively moved to other stew ponds; female trout or triploids grows to one kilogramme in weight in about 15 months, a Brown Trout takes almost three years for the same.  So you can see why Brown Trout cost so much more than Rainbows.  The fish are fed pelleted feed which consists of fish oil and protein etc, it is commercially available and varies greatly in quality.


Triploids and female trout are preferred for stocking purposes since, not only are they cheaper to rear, the triploids cannot breed with the indigenous strain of fish and disturb the existing genetic pool.  Diploid (fish capable of breeding) trout from Scotland were imported to Blagdon Reservoir in Victorian times to increase numbers and improve the wild Brown Trout strain naturally occurring from the River Yeo which feeds it.

 Staff at BW Hatchery hope that, in the near future, the facility will be replaced by a modern unit;


All present thoroughly enjoyed the visit, found it to be very educational and left knowing a little bit more about the technology that supports our sport.  Our thanks should be formally sent to the staff at BW’s fish hatchery.


Nigel Andrews


December 2011.