Newly discovered virus could be responsible for thousands of fish deaths on Norfolk Broads

PUBLISHED: 18:30 31 January 2017 | UPDATED: 00:19 01 February 2017

230,000 fish were rescued on Hickling Broad in 2015. Picture: Environment Agency.

230,000 fish were rescued on Hickling Broad in 2015. Picture: Environment Agency.


Scientists are today another step closer to finding out the cause of thousands of fish deaths on the Norfolk Broads.

230,000 fish were rescued on Hickling Broad. Picture: Environment Agency.230,000 fish were rescued on Hickling Broad. Picture: Environment Agency.

Research by the John Innes Centre (JIC) and the University of East Anglia has led to the discovery of a new virus, which could be responsible.

It is believed that the pathogen causes a specific type of algae, called Prymnesium parvum, to release toxins into the water.

Back in 2015, a toxic algal bloom was responsible for killing thousands of fish in the Broads.

Scientists at Norwich Research Park are now working tirelessly to understand the exact conditions needed for the toxin to be released.

Meanwhile, the Environment Agency is planning to spray peroxide onto a section of Hickling Broad to see if it can prevent fish deaths in the future.

A stakeholder meeting was held at the JIC, off Colney Lane, earlier today to discuss the project’s latest findings.

Ben Wagstaff, PHD student at the JIC, said: “This is the first time that an accurate profile has been put together of a Prymnesium population over a year and how it changes. We think that a viral infection is causing toxic episodes, but how it is doing that we are not sure.”

More than 250 water samples have been taken from several areas of Hickling Broad over the past 12 months.

While there was a significant increases in Prymnesium and the virus during certain points in the year, neither coincided at the same time.

Further research is now needed to determine what environmental factors lead to such increases and how it can be prevented.

Around 230,000 fish had to be rescued and relocated from a corner of Hickling Broad following a Prymnesium algal bloom in 2015.

That same spot, near the Whispering Reeds boat yard, is to be sprayed with peroxide between March and April this year.

Steve Lane, fisheries specialist at the environment agency, explained how the chemical could save fish in the future.

He said: “when you get that many fish stuck in a small area, they suffocate themselves because there is not enough oxygen. Peroxide is a way of oxygenating the water, and research has also found that it kills the algae and neutralises the toxin.

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