How do fish survive the floods?

river ouse flood

Image source: RobertChlopas /
York, flooded when the Ouse broke its bank

When the floodwaters rise, fish hunt for places to shelter; riverbanks, side streams or under bridges where the current is sluggish. But sometimes, things go wrong.

We take a look at what happens to fish when rivers burst their banks, and what you can do to help.


dead fish at the goring

Image source: Matt Drew, EA
After the flood

Hundreds of bream and carp, some of them thirty years old, were stranded in floodwater near the River Severn in 2012. Rescuers were exhausted after searching ten acres of floodwater, but their dogged determination paid off and they saved the fish. Tom Sherwood from the Environment Agency’s fisheries department spells out how fish get trapped:

“As the water recedes, most fish will find their way back to the river, but you do get instances where there is a sump of water left and the fish are left behind.”

Disaster struck when thousands of fish came to a grisly end in 2014. A local man was horrified to discover the dead minnows, perch, dace and roach near the River Thames in Goring, after receding floodwaters left them desperate for oxygen.

An unexpected Discovery

There was something fishy going on at an Aberdeen golf club during recent floods. The Greenkeeper was amazed to find a salmon trapped in one of the bunkers:

“When I got down to the third hole, I saw that the bunker was flooded. However, when I looked closer I saw a fish swimming about. I couldn’t really believe what I was seeing, so I phoned the course manager to tell him and he thought I was winding him up.”

It took five people to catch the salmon. But their persistence paid off, and finally the fish slithered back into the River Dee.

Pollution and pesticides.

rain washing soil away

Image source: Angling Trust
Rain washing soil away into the river

”Catastrophic changes in the way we manage soil and grow crops make flooding more likely, says writer George Monbiot. His Guardian article laments the increasing rate of soil erosion over the past century:

“Worst of all is the shift towards growing maize. In three quarters of the maize fields in the South West, the soil structure has broken down to the extent that they now contribute to flooding.”

Water that pours off these fields contains a lethal mixture of soil, pesticides and fertilisers. The Inside Angle’s Mark Lloyd is blunt about the effects:

“Rain on wet fields runs into rivers, carrying rain with it slurry, soil, pesticides and fertilisers. These are lethal to fish and the invertebrates they eat.”


How can anglers help?

fish on worcester racecourse

Image source: Environment Agency
Floundering fish

Image Source: The Environment AgencyHow often do you go fishing? Anglers are in prime position to spot any trouble. Always make sure you carry the Environment Agency’s incident phone number (0800 80 70 60) just in case. Staff are on duty 24/7 ready to respond to calls about distressed fish or polluted rivers.

Early warning

racecourse fish rescue

Image source: Environment Agency
Just in time!

It was local people who came to the rescue when Worcester Racecourse flooded in 2007. At the time, coarse fish were in the shallows of the River Severn spawning, and when it burst its banks, a flooded racecourse seemed the perfect venue to head for.

But when the waters receded, fish got trapped in small pools of warm water. The situation was critical – warm water holds less oxygen than cold water. The fish had to be caught and moved before they suffocated.

A member of the public averted disaster just in time to save tens of thousands of fish. But more would have been saved if the alarm had been raised earlier. In 2014, when the same spot flooded, the Environment Agency reacted much more quickly and all of the fish were rescued.

Do you have your licence?

rod licence

The all-important licence!

You fund the Environment Agency through your rod licence fee. The £27 million raised last year provided funding for emergency responses as well as the specialist equipment needed to restore oxygen levels or rescue stranded fish.

But the Environment Agency still relies on anglers to call it in if there’s a problem. So next time the skies are full of rain, don’t let a bad forecast put you off. If you have a floatation vest to hand and you’ve checked that the current isn’t too strong, grab your waders, pocket your mobile phone and head to your local river.

You never know, it could be your turn to save some stranded fish.