Members of the partnership formed by the Environment Agency, the Pike Anglers and the Broads Angling Strategy Group to protect fish threatened by the North Sea were called out for the first time to mount a successful rescue operation following a serious overnight North Sea penetration into the Broads that left possibly thousands of fish casualties in the River Thurne.

Under the leadership of EA fisheries officers Graham Gamble and Steve Lane, shoals of distressed fish were transferred into the safety of the Potter Heigham boatyard lagoons whose safety barrier had been put in place following Thursday's flood warning.

But because the annual autumn migration of fish into safe havens beyond the limit of saline incursion was still ongoing and the fact that the previous ebb tides had left river levels well below normal, many bream, roach, perch and pike were caught up in a sudden borewave that surged up river at a tremendous pace.

Dead fish were also spotted in the Rivers Bure and Yare and this week fishery officers were operating sonar devices and underwater cameras to determine the full scale of this natural disaster that reopens the controversial debate why the Norfolk Broads river basin is the lone example along the east coast without some form of a protective tidal barrier, lock gate or sluice.

In January 2011 a tidal energy plan to locate a self-funding installation that would act as a sea barrier while generating power for the national grid was hailed by Broads Authority chief John Packman as 'a great example of ground breaking work the SDF should fund', while angling leaders greeted the proposals as the best development to protect fish for decades. The plan has not seen the light of day since.

On Monday, Mark Lloyd, CEO of the Angling Trust, gave the EDP a candid, realistic assessment of the state of play.

'This is clearly a major problem that will get worse if sea levels rise without an easy solution. I think that a tidal barrage is very unlikely to be viable for environmental and economic reasons, but the Angling Trust will do all we can to find away of protecting fish stocks.'

Steve Roberts chairman of the Norwich Pike Club and Tony Gibbons the NDAA chairman and member of the Broads Angling Strategy Group insist that only a tidal barrier would suffice.

'Over the years fish stocks have been resilient in the face of repeated dangers and fishing this season has been brilliant.

'However, without proper protection I am certain our Broads and rivers will eventually become a salt water habitat,' said a pessimistic Gibbons.

The Broads Authority does not dismiss a barrier plan. In response to the question on the subject press relations officer Hilary Franzen said the BA was considering many options, including a barrier scheme, working with nature to establish wash lands, to accommodate extra water but at this stage there were no detailed proposals for action.

Meanwhile, test fishing by Yarmouth anglers Kevin Paynter and Barry Harding on the Thurne at Martham on Saturday produced mixed nets estimated around 10lbs from water still carrying a distinctly saline flavour.

Today's open event on the same stretch may offer anglers more hope that substantial numbers of bream and roach have survived.