Record-breaking weight of fish reared at national farm
More than 500,000 fish have been reared and released into the wild to replace species that have been lost to pollution.
The Environment Agency said a "record-breaking weight of fish" was produced at its national fish farm in Calverton, Nottinghamshire, in 2019.
More than 12 tonnes of fish left the farm, almost a tonne more than in 2018.
They will boost populations where fish have been lost and go into areas where natural reproduction is low.
The agency said it restocked rivers with 520,475 coarse fish, including chub, barbel, dace, roach and crucian carp, along with 7.6m "advanced reared larvae".
Alan Henshaw, from the farm, said: "We're pleased to have had another record-breaking year at the fish farm.
"Great care is taken to ensure that every fish we produce is fit for purpose so they can survive when stocked out into the wild."
The fish spend about 18 months at the farm while being fed live natural food and are also trained in "flowing conditions", said Mr Henshaw.
Income from fishing licence fees is put directly into the fisheries, said Heidi Stone, the fisheries manager for the agency.
"The fish [the farm] produces plays an important role in the Environment Agency's work to restore, improve and develop sustainable fisheries in England," she said.
The agency added the recent hot weather has led to low levels of water in the UK, forcing a number of fish rescues.
The heat caused low flows in some rivers and led lakes and ponds to warm up, causing a fatal drop in oxygen levels.
The public has been urged to get in touch if they see fish in distress.
Follow BBC East Midlands on Facebook, Twitter, or Instagram. Send your story ideas to [email protected].