Jason Bean
Senior Member
Below is a letter my local club sent to our local fisheries officer, We are lucky that he is working with us. It would be too easy to say the otters were having them all
I'll post the reply if anyone is interested
Cheers
Jason
Kidlington Angling Society
River Cherwell, Thrupp-Hampton Poyle-Kidlington 2009-2010 season
Current fish Stocks This past season has seen the trend continue of fewer small fish in the river.Worryingly, specimen anglers that previously targeted barbel are now going after specimen chub due to the scarcity of barbel. These anglers are reporting that thenumbers of chub are declining also. Perhaps this signals a similar pattern that occurred with barbel in the late 90’s early 2000 where barbel size increased as numbers got fewer leading to a total collapse of stock capable of spawning. Barbel could, without the intervention of stocking and improved habitat, completelydisappear off the Cherwell. Chub do however seem to be in numbers to recover should the environment improve.Match fishing has also been a strong indicator of the numbers of each species of fish in the river. Winners of matches do so with one or more (but not many) large fish whereas the rest of the anglers catch either very little or blank. At a guess 50% would be a fairly accurate blank rate.Other fish such as Bream, Perch, Roach, Gudgeon and Dace do show in isolated pockets but are not wide spread. Tench and Carp while not common in the river did show more often, but it does appear that these must be in very small numbers now, if still there at all.A noted point this past year is the small numbers of minnow, bleak and in earlyseason matches brown trout would normally show but no reports this year.
Water Quality Overall it appears that the water quality of the Cherwell is good. The EA’s own data (2008) shows the river in good condition with the only concern being the higher levels of phosphates and nitrates in the river. This may be part of the natural make up of the river, however the EA could confirm whether these higher levels do affect fish stocks and whether they are raised by outside influences and could be reduced.
Nitrates: 4
Phosphates: 4
Scored 1-6, 1 being good
Biology: B
Ammonia: A
Dissolved Oxygen: A
Scored A-F, A being very good
Other concerns regarding the water quality is the pH level, a pH test is performed to establish the exact acidity or alkaline level in any chemical. The rainfall comes to thevalley as pH neutral 7.0, but en-route to the river it leaches through the soil, where itpicks up mineral deposits and along the whole Cherwell valley the soil type is one ofsandy loam and/or brash which does contain limestone which is an alkali substance. But crucially it would only lead the rivers water to appear as a very mild alkali (pH 7.60/7.70 would be expected), and it would be expected that without 'non-natural'influences that this figure remained stable from year to year, especially if the tests are
performed roughly in the same month annually. This though is not the case on the Cherwell; The records date back to 1993.
1993
Somerton pH 7.80
Kidlington pH 7.82.
1994
Somerton pH 7.87
Kidlington pH 7.90.
1995
Somerton pH 8.00,
Kidlington pH 8.03,
This trend continues right up to 2005 when Somerton and Kidlington levels peaked at pH 8.18.Points to note; the soil types and subsequent mineral deposits are obviously unchanged, therefore it’s not that. Agri-chemicals are used to a much reduced level and there are very few arable fields adjacent to the river and if agri-chemical usage can be blamed, should the river plus its tributaries be registered as NVZ (Nitrate Vulnerable Zone). Last 'usual cause' of alkaline residues going in to a river; Sewage, treated or otherwise is a major source of Ammonia and resulting Nitrates.In the last decade Banbury's population has increased by approx’ 15%, so byreasonable deduction that's 15% more water abstracted north (upstream) of Banburyand 15% more sewage going back in south (downstream) of the town. More toxins and less water for them to be diluted into. A point of interest which the EA could confirm is whether chemicals that cause same sexing of fish are in the river and whether there are any concerns regarding this. Another concern would be legal or illegal discharges of sewage or other untreated water pollution into the river and whether this has any effect, it’s something we never hear of and would like to know if this occurs. Biodiversity It appears that over a number of years the biodiversity of the river has increased. Has this been for the good of the natural balance of the environment though?Regarding fish stocks the effect has been to reduce the numbers within the individual species severely, barbel being a prime example. From an angler’s perspective alien and invasive species such as signal crayfish, cormorant and mink are greatly impacting this. It is noted that the amount of kingfishers on the river is very healthy with it being the norm to see one on every visit to the river with the surrounding fields being home to fallow deer and muntjac. Otters are more present on the river, while they are not often seen, fish kills particularly of large fish are occasionally observed.It seems that the biodiversity is not in a seemingly healthy natural balance with recent external man-made influences, having a severe effect on the underwater environment.It could be that now there is little interest in conserving the underwater biodiversity of the river and there being no local fisheries action plan, that the interests of the river lie within the greater public.
Should there be another Cherwell District Council biodiversity action plan proposed,the interests of the river and anglers could be included for consideration.The affect of signal crayfish in the river must be effecting the aquatic biology. Macro-invertebrates are extremely important to successful fish stocks and the density of signal crayfish in the river surely take up a large percentage of biomass that fish would normally be part of. It would be interesting to know whether it is the case that the signals do actually eat the majority of food source available to fish stocks. Signal crayfish are notorious for eating fish eggs, and, with the decline in numbers of fish,combined with the silting of gravel beds, this must have an enormous effect on our fish stocks ability to reproduce. Signal crayfish, which burrow into the bank side are collapsing banks, spreading silt into the river and, in recent years, the holes in the bank are becoming more numerous.
Ecology, abstraction and flood prevention
The consequence that the rivers changing environment has on fish stocks does appear to be a major issue in this area. The impounding of the Thrupp stretch does not allow for migration into the area from further downstream. The effects of flooding and future flood prevention work could further impact on the area and every effort regarding this should not result in further damage to a struggling, out of balance environment. Any work that the EA flood prevention team carry out to alleviate flooding on KAS stretches must be consulted with the KAS committee before proceeding. This being to avoid what happened recently where the lower stretch at Bransons was completely stripped bare, totally removing any cover for fish to use to avoid predators. Species such as chub, barbel and perch rely on in-stream cover forsurvival and it is noted since this cover was removed on that stretch, fewer of these fish have been caught.The river is now more prone to heavy flash flooding, whether this is down to so-called global warming or more local issues only time will tell. The expanding local flood plain and need for housing will put further pressure on the river. It is worth noting that the local ditch networks are not maintained or cleared, particularly around white bridge. In years past you would imagine these were dug and maintained to make adjacent fields available for farming, if these were re-instated and connected to the river this may benefit fish stocks, enhance the environment and possibly help with flood relief. Siltation of gravel spawning sights appears to be effecting fish such as dace, barbel, gudgeon and chub. One reason for this would be the turbidity which appears to be caused by the large amount of signal crayfish in the river and low summer flow rates. British Waterways greatly influence the river Cherwell and are perhaps now part of the reason for poor summer flow rates, the large increase in pleasure craft on the Oxford canal and with the interlinking of the canal and river must be having a detrimental effect on the Cherwell. We understand British waterways can legally abstract as much water as they need to serve the canal. Observations from this are that in the summer, in low river conditions, the canal can be more of a river than the river itself. We understand that this is something the EA are pursuing in respect to changes in the law that allows British waterways to abstract as much water as they like without regard for the surrounding environment. It would be interesting to know the facts around this issue.
Signal Crayfish The general consensus amongst local anglers is that signal crayfish are possibly the main contributing factor to declining fish stocks on the river As previously mentioned, the environmental changes they bring verge on being a pollutant and any future ways of removing them would be a major step in improving the river.
Mink As anglers we do not know the full impact they have, however, they do seem to be more resident on the river compared to otters. The understanding that otters displace mink does not appear to be happening on this stretch.
Cormorant The lower stretch towards Kidlington where the river deepens and widens is the area where cormorants tend to predate. Large numbers have not been spotted but during the winter months small numbers regularly visit this area. This gives reason for keeping as much in-stream cover as possible.Otters While otters have been in the area for quite a number of years the full impact is notfully known. Our concern on this subject is that, due to the lack of smaller fish, the target for otters will be the few remaining stocks of larger fish.
Fish removal Other clubs particularly those on the Thames comment on Eastern Europeans targeting fish and illegally removing them. As a club this is not something we have noticed and are not overly concerned about at the moment.
Canoe access This could be a concern for our club and the fragile environment of the local river. While the club is not anti-canoeist we do understand that the EA recreational policies are to actively encourage greater use of the waterways. In the future should consultations between canoeists, the EA and land owners takeplace KAS would want to be part of them to ensure respect for anglers and the environment be of paramount importance should any agreements be reached.
The future We as anglers have put this together with our limited environmental knowledge and it’s based on our own observations. If the EA could inform us of any other contributing factors to the Cherwell’s decline or if our views are misinformed we would like the EA to let KAS know.The recognition of the current state of fish stocks needs to be taken seriously by the EA and we are grateful for stocking and habitat works already taken place. We do hope the EA look long term at this small stretch of river in particular while considering the whole river as well. We believe regular stocking needs to take place until major habitat enhancement works have been carried out and fish stocks can hold their own.The problems facing our stretch of river are numerous and, at this moment in time habitat improvement and the stocking of fish appear to be the only options currently available.
We feel the problems the Cherwell face will, in the future, affect other smaller rivers and this river should be used as a test bed for measures to combat these problems.It’s quite apparent that without recent stocking, indigenous barbel could soon have disappeared; recent surveys have shown how precarious the stock levels are and how fast they have declined. Being a European key indicator/Thames BAP species it shows how urgent habitat works and stocking are needed.Should the EA fisheries, conservation, recreational and flood prevention departments wish to carry out works on the KAS controlled Cherwell stretches please contact the secretary of the club Mr X, Treasurer Mr X or committee member Mr X. We hope our report is passed on to relevant people within the EA departments listed above. The aim of this report is for it to be kept as a KAS archive so that in the future, we can look back to where we were. In years to comethese reports will hopefully show improvements both for fish stocks, anglers and the wider environment.
Secretary
Mr XXXXXX
Treasurer
MrXXXXXX
Committee member
Mr XXXXXXX
I'll post the reply if anyone is interested
Cheers
Jason
Kidlington Angling Society
River Cherwell, Thrupp-Hampton Poyle-Kidlington 2009-2010 season
Current fish Stocks This past season has seen the trend continue of fewer small fish in the river.Worryingly, specimen anglers that previously targeted barbel are now going after specimen chub due to the scarcity of barbel. These anglers are reporting that thenumbers of chub are declining also. Perhaps this signals a similar pattern that occurred with barbel in the late 90’s early 2000 where barbel size increased as numbers got fewer leading to a total collapse of stock capable of spawning. Barbel could, without the intervention of stocking and improved habitat, completelydisappear off the Cherwell. Chub do however seem to be in numbers to recover should the environment improve.Match fishing has also been a strong indicator of the numbers of each species of fish in the river. Winners of matches do so with one or more (but not many) large fish whereas the rest of the anglers catch either very little or blank. At a guess 50% would be a fairly accurate blank rate.Other fish such as Bream, Perch, Roach, Gudgeon and Dace do show in isolated pockets but are not wide spread. Tench and Carp while not common in the river did show more often, but it does appear that these must be in very small numbers now, if still there at all.A noted point this past year is the small numbers of minnow, bleak and in earlyseason matches brown trout would normally show but no reports this year.
Water Quality Overall it appears that the water quality of the Cherwell is good. The EA’s own data (2008) shows the river in good condition with the only concern being the higher levels of phosphates and nitrates in the river. This may be part of the natural make up of the river, however the EA could confirm whether these higher levels do affect fish stocks and whether they are raised by outside influences and could be reduced.
Nitrates: 4
Phosphates: 4
Scored 1-6, 1 being good
Biology: B
Ammonia: A
Dissolved Oxygen: A
Scored A-F, A being very good
Other concerns regarding the water quality is the pH level, a pH test is performed to establish the exact acidity or alkaline level in any chemical. The rainfall comes to thevalley as pH neutral 7.0, but en-route to the river it leaches through the soil, where itpicks up mineral deposits and along the whole Cherwell valley the soil type is one ofsandy loam and/or brash which does contain limestone which is an alkali substance. But crucially it would only lead the rivers water to appear as a very mild alkali (pH 7.60/7.70 would be expected), and it would be expected that without 'non-natural'influences that this figure remained stable from year to year, especially if the tests are
performed roughly in the same month annually. This though is not the case on the Cherwell; The records date back to 1993.
1993
Somerton pH 7.80
Kidlington pH 7.82.
1994
Somerton pH 7.87
Kidlington pH 7.90.
1995
Somerton pH 8.00,
Kidlington pH 8.03,
This trend continues right up to 2005 when Somerton and Kidlington levels peaked at pH 8.18.Points to note; the soil types and subsequent mineral deposits are obviously unchanged, therefore it’s not that. Agri-chemicals are used to a much reduced level and there are very few arable fields adjacent to the river and if agri-chemical usage can be blamed, should the river plus its tributaries be registered as NVZ (Nitrate Vulnerable Zone). Last 'usual cause' of alkaline residues going in to a river; Sewage, treated or otherwise is a major source of Ammonia and resulting Nitrates.In the last decade Banbury's population has increased by approx’ 15%, so byreasonable deduction that's 15% more water abstracted north (upstream) of Banburyand 15% more sewage going back in south (downstream) of the town. More toxins and less water for them to be diluted into. A point of interest which the EA could confirm is whether chemicals that cause same sexing of fish are in the river and whether there are any concerns regarding this. Another concern would be legal or illegal discharges of sewage or other untreated water pollution into the river and whether this has any effect, it’s something we never hear of and would like to know if this occurs. Biodiversity It appears that over a number of years the biodiversity of the river has increased. Has this been for the good of the natural balance of the environment though?Regarding fish stocks the effect has been to reduce the numbers within the individual species severely, barbel being a prime example. From an angler’s perspective alien and invasive species such as signal crayfish, cormorant and mink are greatly impacting this. It is noted that the amount of kingfishers on the river is very healthy with it being the norm to see one on every visit to the river with the surrounding fields being home to fallow deer and muntjac. Otters are more present on the river, while they are not often seen, fish kills particularly of large fish are occasionally observed.It seems that the biodiversity is not in a seemingly healthy natural balance with recent external man-made influences, having a severe effect on the underwater environment.It could be that now there is little interest in conserving the underwater biodiversity of the river and there being no local fisheries action plan, that the interests of the river lie within the greater public.
Should there be another Cherwell District Council biodiversity action plan proposed,the interests of the river and anglers could be included for consideration.The affect of signal crayfish in the river must be effecting the aquatic biology. Macro-invertebrates are extremely important to successful fish stocks and the density of signal crayfish in the river surely take up a large percentage of biomass that fish would normally be part of. It would be interesting to know whether it is the case that the signals do actually eat the majority of food source available to fish stocks. Signal crayfish are notorious for eating fish eggs, and, with the decline in numbers of fish,combined with the silting of gravel beds, this must have an enormous effect on our fish stocks ability to reproduce. Signal crayfish, which burrow into the bank side are collapsing banks, spreading silt into the river and, in recent years, the holes in the bank are becoming more numerous.
Ecology, abstraction and flood prevention
The consequence that the rivers changing environment has on fish stocks does appear to be a major issue in this area. The impounding of the Thrupp stretch does not allow for migration into the area from further downstream. The effects of flooding and future flood prevention work could further impact on the area and every effort regarding this should not result in further damage to a struggling, out of balance environment. Any work that the EA flood prevention team carry out to alleviate flooding on KAS stretches must be consulted with the KAS committee before proceeding. This being to avoid what happened recently where the lower stretch at Bransons was completely stripped bare, totally removing any cover for fish to use to avoid predators. Species such as chub, barbel and perch rely on in-stream cover forsurvival and it is noted since this cover was removed on that stretch, fewer of these fish have been caught.The river is now more prone to heavy flash flooding, whether this is down to so-called global warming or more local issues only time will tell. The expanding local flood plain and need for housing will put further pressure on the river. It is worth noting that the local ditch networks are not maintained or cleared, particularly around white bridge. In years past you would imagine these were dug and maintained to make adjacent fields available for farming, if these were re-instated and connected to the river this may benefit fish stocks, enhance the environment and possibly help with flood relief. Siltation of gravel spawning sights appears to be effecting fish such as dace, barbel, gudgeon and chub. One reason for this would be the turbidity which appears to be caused by the large amount of signal crayfish in the river and low summer flow rates. British Waterways greatly influence the river Cherwell and are perhaps now part of the reason for poor summer flow rates, the large increase in pleasure craft on the Oxford canal and with the interlinking of the canal and river must be having a detrimental effect on the Cherwell. We understand British waterways can legally abstract as much water as they need to serve the canal. Observations from this are that in the summer, in low river conditions, the canal can be more of a river than the river itself. We understand that this is something the EA are pursuing in respect to changes in the law that allows British waterways to abstract as much water as they like without regard for the surrounding environment. It would be interesting to know the facts around this issue.
Signal Crayfish The general consensus amongst local anglers is that signal crayfish are possibly the main contributing factor to declining fish stocks on the river As previously mentioned, the environmental changes they bring verge on being a pollutant and any future ways of removing them would be a major step in improving the river.
Mink As anglers we do not know the full impact they have, however, they do seem to be more resident on the river compared to otters. The understanding that otters displace mink does not appear to be happening on this stretch.
Cormorant The lower stretch towards Kidlington where the river deepens and widens is the area where cormorants tend to predate. Large numbers have not been spotted but during the winter months small numbers regularly visit this area. This gives reason for keeping as much in-stream cover as possible.Otters While otters have been in the area for quite a number of years the full impact is notfully known. Our concern on this subject is that, due to the lack of smaller fish, the target for otters will be the few remaining stocks of larger fish.
Fish removal Other clubs particularly those on the Thames comment on Eastern Europeans targeting fish and illegally removing them. As a club this is not something we have noticed and are not overly concerned about at the moment.
Canoe access This could be a concern for our club and the fragile environment of the local river. While the club is not anti-canoeist we do understand that the EA recreational policies are to actively encourage greater use of the waterways. In the future should consultations between canoeists, the EA and land owners takeplace KAS would want to be part of them to ensure respect for anglers and the environment be of paramount importance should any agreements be reached.
The future We as anglers have put this together with our limited environmental knowledge and it’s based on our own observations. If the EA could inform us of any other contributing factors to the Cherwell’s decline or if our views are misinformed we would like the EA to let KAS know.The recognition of the current state of fish stocks needs to be taken seriously by the EA and we are grateful for stocking and habitat works already taken place. We do hope the EA look long term at this small stretch of river in particular while considering the whole river as well. We believe regular stocking needs to take place until major habitat enhancement works have been carried out and fish stocks can hold their own.The problems facing our stretch of river are numerous and, at this moment in time habitat improvement and the stocking of fish appear to be the only options currently available.
We feel the problems the Cherwell face will, in the future, affect other smaller rivers and this river should be used as a test bed for measures to combat these problems.It’s quite apparent that without recent stocking, indigenous barbel could soon have disappeared; recent surveys have shown how precarious the stock levels are and how fast they have declined. Being a European key indicator/Thames BAP species it shows how urgent habitat works and stocking are needed.Should the EA fisheries, conservation, recreational and flood prevention departments wish to carry out works on the KAS controlled Cherwell stretches please contact the secretary of the club Mr X, Treasurer Mr X or committee member Mr X. We hope our report is passed on to relevant people within the EA departments listed above. The aim of this report is for it to be kept as a KAS archive so that in the future, we can look back to where we were. In years to comethese reports will hopefully show improvements both for fish stocks, anglers and the wider environment.
Secretary
Mr XXXXXX
Treasurer
MrXXXXXX
Committee member
Mr XXXXXXX
