It's feared a stream near Gatwick Airport could takes years to recover fully, after pollution killed up to 1000 fish.
High levels of ammonia were detected in a tributary of the River Mole at Horley.
Mature specimens of Barbel, Chub and Pike were among the fish found dead.
Investigations are underway to find the source of the pollution, as Malcolm Shaw reports.
A species of tropical fish has been shown to be able to distinguish between human faces. It is the first time fish have demonstrated this ability.
The research, carried out by a team of scientists from the University of Oxford (UK) and the University of Queensland (Australia), found that archerfish were able to learn and recognise faces with a high degree of accuracy – an impressive feat, given this task requires sophisticated visual recognition capabilities. The fish spit at the face they had been trained to recognise. The study is published in the journal Scientific Reports.
The researchers found that fish, which lack the sophisticated visual cortex of primates, are nevertheless capable of discriminating one face from up to 44 new faces.
In the study, archerfish – a species of tropical fish well known for the ability to spit jets of water to knock down aerial prey – were presented with two images of human faces and trained to choose one of them using their jets. The fish were then presented with the learned face and a series of new faces and were able to correctly choose the face they had initially learned to recognise. They were able to do this task even when more obvious features, such as head shape and colour, were removed from the images.
Environment Agency Fisheries Officers are carrying out a fish survey along the River Thames in Oxfordshire this week.
A specialised electro-fishing ‘boom’ boat will pass an electric current into the water to attract and momentarily stun fish, enabling them to be easily caught. The fish will then be caught and measured by the Environment Agency officers, before they are safely returned unharmed into the river.
The information collected will provide a picture of the river’s fish population, and the results will help the Environment Agency to further understand how factors like water quality, flows and habitat, influence the health of our rivers.
The boom boat is an unusual vessel that has two arms or booms which extend from the front of the boat through which the electric current is passed into the water. There are punts on the side of the boat where officers can catch the fish using nets.
The surveys are done at night because the fish are higher up in the water and there is less boat traffic - making it easier to navigate and fish.
Fisheries Officer, Stuart Manwaring said: “The information collected in these annual surveys helps us to understand the population structure and range of fish species living in our rivers. The data collected helps inform our work to protect and improve the habitat in the Thames, much of which is funded by rod licence fees.
“The Thames Boom Boat surveys in recent years have produced bumper results with many thousands of fish being caught representing around 20 different species in all, but mainly carp, barbel, roach, dace, perch and chub and including some massive specimens.”
A fishmonger in Sussex has been voted best fishmonger in the UK. So what's their secret? The people who run the little shop are delighted of course. But what may surprise many, is that they are based twenty miles and more from the nearest harbour or seashore.
Thousands of fish have been found dead near the River Thames in Goring. The recent flooding has seen exceptionally high river flows over an extended period of time, which has caused some fish to seek refuge on flooded fields and meadows.
Unfortunately, fish can become trapped as result and may die due to suffocation as levels leave them stranded or water quality deteriorates.
The Environment Agency has carried out a number of rescues of trapped fish in the past, and as a result know of a number of historic sites where fish become trapped after flooding.
This week, fisheries officers became aware of fish trapped in a small pond off the River Thames, near Goring. The team used electrofishing equipment to remove the fish, including Perch, Dace, Chub, and Roach, and returned them to the River Thames.
Video. A dead five foot long fish, which weighs as much as a person, has gone on display in Medway. David Johns spoke to shop owner Abdul Hannan about why this big fish is becoming the talk of the town.
The recent heatwave has led to tens of thousands of fish dying in rivers and lakes, with officials racing to rescue many more.
The hot weather and low rainfall that gripped the UK in July can lead to low oxygen levels in water, leaving fish at risk of suffocation or distress, the Environment Agency said.
Heavy rainfall, such as the downpours which followed the heatwave, can cause an increase in diffuse pollution and sediment washed off roads, from sewerage systems and from agricultural land, which also lowers oxygen levels.
There were more than 15 separate incidents in July that led to almost 50,000 fish deaths as a result of the weather, while many thousands more were rescued by Environment Agency teams and partners.
In Tiptree village pond, Essex, the Environment Agency responded to reports of hundreds of fish in distress and 50 dead, and found oxygen levels down to 3%.
With aeration pumps they were able to boost levels to a healthy 40%.
Geoff Bateman, head of fisheries and biodiversity at the Environment Agency, said: "Long periods of hot weather with low rainfall can be deadly for fish.
"The Environment Agency has a 24-hour incident hotline on 0800 807060 and we encourage anglers and people out enjoying rivers, canals and lakes to call if they see fish gasping for air.
A potentially deadly sea creature has gone on display at an Aquarium in East Sussex. The stonefish was handed in to a pet shop in Portsmouth before being given to the Blue Reef Aquarium in Hastings
The Environment Agency is warning the public that ‘pet’ fish and non-native fish should not be placed into their local streams, rivers and lakes because they are breaking the law.
The reminder comes after fisheries officers were called to remove non-native fish found in a stream beside the Great Stour, Kent.
The fish, including at least 50 goldfish, were found by a Mid Kent Fisheries bailiff and reported to the Environment Agency. It is likely that the fish were put into the river from a garden pond.
When ornamental fish are released into rivers they can spread disease and parasites to other fish.
For information about non-native fish, see the Environment Agency’s website.