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content@managingwater.co.uk Conservation & the Environment


may also be used. This provides the capacity to carry more than one order at a time and to introduce accurate numbers of fish at multiple stocking sites with the minimum of netting and handling.


If you would like more information about the fish farm at Calverton please email Alan Henshaw:


Holding tanks


The fish are then sorted by species and an accurate fork length/weight sample taken. All fish are graded according to size using a mechanical grader and accurately counted via computerised fish counters. These greatly reduce handling stress and damage enabling the counting and grading of up to 40,000 fish/hour.


litre tanks. Each tank has its own oxygen and air supply and on occasions, a large trailer


alan.henshaw@environment-agency.gov.uk or write to the following address:- Calverton Fish Farm Moor Lane Calverton Nottingham NG14 6FZ


4,000 Fish stock boosts the River Colne


Last month the Environment Agency restockied the River Colne with 4,000 grayling as part of efforts to return it to one of the best grayling rivers in the country.


Fish stocks in the Huddersfield river were hit two years ago following a pollution incident, which damaged fish populations. Important species


Fish grading Delivery


The fish are now ready for for re-stocking and are transported using a purpose built 6x6 Land Rover on which are mounted a number of 300


River life could be profoundly harmed by


droughts new study warns


Peter Mischenko, fisheries technical officer at the Environment Agency, said: “Grayling are an important species in a watercourse. They require water with a high oxygen content, and so their presence is usually a sign of good water quality.


“Anglers have come from as far afield as Holland to fish for them in the River Colne. This stocking should help to boost numbers


in the river as part of an exercise that was started the year after the pollution incident.”


The young grayling are nearly five months old and have been bred and grown at Calverton. The eggs came from adults caught from West Yorkshire’s River Calder back in March 2012, and the young fish, known as fry, have been grown in a specially designed system that ensures they can thrive in the River Colne.


The fry will continue to grow in the river and some of them will begin to spawn in the spring of 2014. It is hoped that by stocking these young fish over the next few years, the population of grayling in the river will return to healthy numbers.


End


Critically low water levels in many rivers could lead to the partial collapse of food chains that support aquatic life, according to research led by the University of Birmingham published in the journal Nature Climate Change.


This is the conclusion of one of the longest experiments on drought ever conducted in freshwaters.


The research was funded by the Natural Environment Research Council and the Freshwater Biological Association and included scientists from Queen Mary University of London (Dr Guy Woodward), the University of Leeds (Dr Lee Brown), and the Centre for Ecology and Hydrology (Dr Francois Edwards).


The team periodically lowered water flow in artificial streams, mimicking severe drought conditions in natural running waters. They looked at all species in the river, studying the whole food chain, measuring the growth rate of the animals in all populations.


Dr Mark Ledger from the University of Birmingham’s School of Geography, Earth and Environmental Sciences, and lead author of the study, said


38


‘We found that drought changed the make-up of the invertebrate life in the stream community and reduced its diversity by around 25%.’


Dr Ledger added many insects, such as mayflies, were severely affected by drought, as were many large predatory invertebrates, which could not escape. He continued: ’Our study demonstrates that the loss of invertebrates limits the flow of food energy through the food chain, with potentially profound consequences for the health of river ecosystems.’ ’We discovered that, in particular, drought had negative effects on large bodied invertebrates, an important food source for fish, which has significant implications for fisheries.’ Co-author, Professor Alexander Milner, from the University of Birmingham, added: ‘These findings demonstrate that the future intensification of drought, similar to that seen in the UK earlier this year and ongoing in the central and midwestern states of America, can be expected to have major effects on both biodiversity and ecosystem processes in streams and rivers.’


Endangered newts res An endangered species of amphibian wa


Environment Agency staff were quick to respond when they discovered an endangered species of amphibian during routine works in Market Rasen, Lincolnshire.


A team from South Ferriby was carrying out maintenance work at Market Rasen Flood Storage Reservoir when they saw what they believed to be a newt - six feet down a manhole.


They called colleagues with expertise in fisheries and biodiversity who quickly arrived on site. The newt was rescued from the manhole using a pond net and it was confirmed that it was a great crested newt.


After checking other manholes and the surrounding area and confirming that the ‘pot holing’ newt was the only one around, it was released into suitable, safe habitat close by.


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