Post by Hoppy on May 16, 2006 15:52:37 GMT -1
Hampshire Avon salmon under spotlight
The Environment Agency is stepping-up its efforts to discover the secrets surrounding salmon stocks on one of England’s best known salmon rivers - the Hampshire Avon.
The Avon is famous for its Spring salmon. Weighing in excess of 20 lbs, these large fish that have grown to maturity after several winters at sea, are still found in significant numbers in the Avon. However, the Avon has seen a serious decline in salmon numbers and is no longer meeting its conservation limits.
It is important rivers meet these internationally recognised limits if they are to support sustainable populations of salmon.
The Agency currently assesses salmon numbers using catch returns from anglers and netsmen fishing in Christchurch harbour. The netsmen, who are fishing for sea trout, record and release all salmon they catch. Although netting data provides information over part of the salmon run, an additional system was needed to give a complete picture.
Now, using special monitoring equipment including hi-tech cameras, scientists aim to accurately record the number of salmon travelling up the Avon to spawn throughout the entire year.
The equipment has been installed at Knapp Mill near Christchurch where fish movements are being closely monitored 24 hours a day using a purpose-built fish counting device and bank of eight digital video cameras.
Any fish above a certain size that pass through the counter are automatically caught on camera together with the date and time. The data is stored on a computer where images of individual fish can be viewed. The system allows scientists to calculate an approximate size of the fish and for the species to be determined.
Since it was re-installed in February, more than 200 salmon have been recorded migrating up the Avon by the new equipment at Knapp Mill.
The research has shown it is not only fish that pass through the electronic counter. While fine-tuning the equipment, Agency scientist Jon Bilbrough saw the unmistakable image of an otter on his computer screen.
‘I was rather surprised, but also pleased to capture this unexpected visitor on film. The presence of otters on the Avon is a positive sign that the river is in good health,’ said Jon, who was appointed by the Environment Agency at the end of 2005 to head-up the fish monitoring project at Knapp Mill.
Ultimately, Jon aims to improve the system so that Agency staff can directly access the fish counter images and data remotely from their office. He also plans to install a pair of underwater video cameras that will make it easier to distinguish between salmon and sea trout.
One major improvement is the speed at which images can be retrieved. With earlier systems a person had to watch hours of video to find the image they were looking for. Now, footage can be retrieved in seconds.
‘The early results from this latest monitoring are very encouraging. Used in conjunction with the data from rod and net catches, it will be a very useful tool and should give us a much better understanding of salmon stocks on the Hampshire Avon,’ said Jon.
The results of the monitoring including photographs of fish will shortly be displayed on the website of the Royalty Fishery whose anglers fish the Avon in the vicinity of Knapp Mill.
The Environment Agency is stepping-up its efforts to discover the secrets surrounding salmon stocks on one of England’s best known salmon rivers - the Hampshire Avon.
The Avon is famous for its Spring salmon. Weighing in excess of 20 lbs, these large fish that have grown to maturity after several winters at sea, are still found in significant numbers in the Avon. However, the Avon has seen a serious decline in salmon numbers and is no longer meeting its conservation limits.
It is important rivers meet these internationally recognised limits if they are to support sustainable populations of salmon.
The Agency currently assesses salmon numbers using catch returns from anglers and netsmen fishing in Christchurch harbour. The netsmen, who are fishing for sea trout, record and release all salmon they catch. Although netting data provides information over part of the salmon run, an additional system was needed to give a complete picture.
Now, using special monitoring equipment including hi-tech cameras, scientists aim to accurately record the number of salmon travelling up the Avon to spawn throughout the entire year.
The equipment has been installed at Knapp Mill near Christchurch where fish movements are being closely monitored 24 hours a day using a purpose-built fish counting device and bank of eight digital video cameras.
Any fish above a certain size that pass through the counter are automatically caught on camera together with the date and time. The data is stored on a computer where images of individual fish can be viewed. The system allows scientists to calculate an approximate size of the fish and for the species to be determined.
Since it was re-installed in February, more than 200 salmon have been recorded migrating up the Avon by the new equipment at Knapp Mill.
The research has shown it is not only fish that pass through the electronic counter. While fine-tuning the equipment, Agency scientist Jon Bilbrough saw the unmistakable image of an otter on his computer screen.
‘I was rather surprised, but also pleased to capture this unexpected visitor on film. The presence of otters on the Avon is a positive sign that the river is in good health,’ said Jon, who was appointed by the Environment Agency at the end of 2005 to head-up the fish monitoring project at Knapp Mill.
Ultimately, Jon aims to improve the system so that Agency staff can directly access the fish counter images and data remotely from their office. He also plans to install a pair of underwater video cameras that will make it easier to distinguish between salmon and sea trout.
One major improvement is the speed at which images can be retrieved. With earlier systems a person had to watch hours of video to find the image they were looking for. Now, footage can be retrieved in seconds.
‘The early results from this latest monitoring are very encouraging. Used in conjunction with the data from rod and net catches, it will be a very useful tool and should give us a much better understanding of salmon stocks on the Hampshire Avon,’ said Jon.
The results of the monitoring including photographs of fish will shortly be displayed on the website of the Royalty Fishery whose anglers fish the Avon in the vicinity of Knapp Mill.