https://environmentagency.blog.gov.uk/2017/01/31/when-the-weather-gets-tough-calverton-gets-going/

When the weather gets tough, Calverton gets going

Calverton Fish farm near Nottingham is a crucial part of the Environment Agency’s toolkit for improving fisheries around the country. As the weather turns colder and many anglers start thinking about hanging their rods up for the winter, staff at the farm enter their most exciting period as they look to release fish into the wild. Alan Henshaw who runs the farm tells us about the stocking work his team have been doing around the country.

Calverton fish farm

As Team Leader for the fish farm it gives me immense pleasure to see the fish we produce helping regenerate populations in rivers the length and breadth of the country. The team at the farm spend the year breeding and growing on quality, pure bred, disease free fish which we stock out into the wild in the run up to Christmas. This is because water temperatures are low and this minimises any stress on the fish we release and ensures the best possible survival rates.

It would be counterproductive to stock hatchery fish on top of healthy natural stocks so we don’t stock in every water around the country. Instead we take a science based approach with fish going into rivers which have been hit by pollution or where surveys show us that natural populations could do with a boost. Many of our industrialised rivers have improved dramatically in water quality over the last 30 years and it is here that the fish we introduce can make a significant and lasting difference to fish populations and angling for years to come.

In addition, we do valuable work helping still water populations to recover after fish have been lost and also help in the development of new fisheries in areas where there are limited opportunities for young and disabled anglers.

Over the past 3 years we have also been working closely with the National Crucian Conservation Project by breeding and supplying genetically pure fish for stocking into specially selected ponds throughout the country where they cannot interbreed with carp or other fish. This will help ensure the survival of true crucian carp for generations to come.

Second year crucian carp and rudd at Calverton fish farm

During 2016 we stocked a approximately 400,000 fish aged up to 18 months along with millions of fry. These were made up of 9 species:

  • Barbel
  • Bream
  • Chub
  • Roach
  • Dace
  • Rudd
  • Tench
  • Crucian carp
  • Grayling

My team and I are always working to improve the quality of the fish we produce so this year, we reduced the numbers of fish in each of the ponds. These lower stock densities meant the fish had more room to grow and less competition for food. This has resulted in much bigger fish with an average increase in weight of almost 40%. I am really pleased with the results and these are on average, the largest fish we’ve ever produced at Calverton. Their increased size means that they will have the best possible chance of survival.

Fish from Calverton have been stocked across the whole of the country in places where our surveys have shown they will deliver the greatest benefit to stocks and angling.

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