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Reasons for Barbel population decline

Lawrence i just delved into the link you provided...they seem to be focusing on roach in the main but why would it not apply wider?
 
Most definitely, Roach are a cyprinid as Barbel are, in some cases Barbel (if they are present) can suffer more so because of their feeding habits of how they feed and where they feed...
 
Well on a brighter note....livers recover well, and quickly, if starved of that which is damaging them (e.g. alcohol, fat...). So IF high-oil pellets ARE negatively effecting fishes' livers, then a 3 month 'abstinence' may lead to (at very least a partial) recovery.
Another good reason for maintaining the close season eh:eek:

Is it possible that fat deposits around the liver will lead to diabetic barbel? If so, the result is that they will not be able to breed, hence the decline in stocks.
 
I have heard that the high fat content of the pellets can cause liver damage in Barbel, we have to remember, these pellets were designed to get maximum growth of farmed fish, in the shortest possible time, they are not designed for longevity and healthy lives....
 
Pete Reading stated;

“You can sex mature barbel by looking at the vent, near the anal fin; females have a fleshy protruding tubular vent, males have a single small hole flush with the skin, but the smaller the barbel the harder it is to see.

At one time Calverton selected the larger fish for some stockings, but as far as I am aware now stock the whole size range from that year class to ensure no sex selection occurs.
I do not think it likely that the sex ratio will vary much within stocked fish anyway, and have any real effect of spawning success.

Far more likely candidates for poor spawning success and recruitment are the obvious ones of poor habitat linked with low flows; barbel need plenty of clean gravel and clean water flowing over it to spawn successfully, plus refuge areas for fry to develop and over-winter in safely.

A combination of other negative factors, such as predation on fry by crays,algae choking eggs, unseasonal flood events, will all play a part in limiting populations.
There will not be a simple answer to what is a very complex question, but interesting to discuss all possibilities.

Hampshire Avon is full of tiny barbel this year, with baby fish from the last two years of spawning in great abundance, so something was right recently; be interesting to see how many survive in the next few years.”

Personally, I think Pete’s comment above is one of the most interesting made on this thread.

There is no doubt that poor recruitment lies at the heart of the problem on some rivers. I seriously doubt that the aquaculture industry has anything to do with it and would be looking into other areas. Take agricultural practices for example. How does this affect some rivers and not others?

Taking the Trent as an example simply because it’s one of the UK rivers that is doing extremely well today. If you look at the type of agriculture adjacent to the Trent a huge proportion of it is not arable but pasture. This is due in part to the geology of the Trent valley which is extremely rich in gravels which makes for poor agricultural land. As such, the Trent does not suffer from extensive agricultural run off from arable land that other rivers do.

Many of the effects on rivers from agricultural practices include;

Land drainage

Agricultural drainage impacts on the water and sediments of the river system. Land drainage has been used since the mid 18th century to increase the suitability of land for cultivation. As a consequence, it has been suggested that in times of flooding or heavy rain, water levels have risen and fallen much faster (i.e. floods have become more flashy) as a result of drainage

Drainage and ditching lower the water table to enable agriculturally desirable plants to grow more productively. Water falling on the land is transported away more effectively. Thus, in drained catchments, river flow matches the rainfall profile more closely than in a natural catchment (although there will be a time-lag relating to catchment characteristics and the preceding soil saturation level). Drainage reduces the natural buffering capacity of the catchment against floods, so the magnitude and frequency of floods downstream may be increased. Conversely, as the natural 'sponge' effect of the land is reduced, drained land may be drier for longer. Lowering of the water table can be detrimental to wetland communities


Generally, field drains are not responsible for large sediment inputs, but do cause an accelerated throughput of water. They constitute a long lasting alteration of the natural flow regime and have become part of the 'natural' process of surface water run-off

Abstractions for irrigation

Unregulated water abstraction for crop spraying and irrigation reduces the flow left in the stream. This is particularly significant during periods of low flow when a given extraction rate takes a greater percentage of the total discharge. Aquatic flora and fauna will thus lose habitat, and pollution will be less diluted in periods of abstraction and low flow.

River engineering works

Piecemeal bank protection is often undertaken at sites where farmland is being eroded. Methods include dumping boulders, concrete and car bodies against the eroding bank. The use of such 'hard' material tends to alter instream flow dynamics, deflecting the main current and causing bank erosion immediately downstream. Traditionally, gabion baskets and rip-rap have been used to provide long-term bank protection. They are now widely questioned on environmental grounds as they are visually intrusive, reduce bankside habitat availability and alter natural instream and bankside processes. Other 'hard' bank protection methods include, the use of current deflectors (though this may cause erosion on the opposite bank), the use of a stone berm at the toe of the bank, and bank reprofiling to reduce bank slope Soft engineering involves planting and the use of geotextile filter layers, and aims to dissipate rather than deflect the river's energy. It is less obtrusive than 'hard' engineering. Good practices for river engineering are detailed in Hoey et al (1995).

Ploughing and crop cultivation

Soil erosion occurs when there is a combination of heavy rain or wind, and exposed soil. Erosion by water most commonly occurs where there are clear routes for the run-off to follow, such as plough furrows and tyre wheelings running up and down the slope. The impact of erosion upon the river system is greater during winter, when an increased sediment load due to exposed soil or high winds, and faster run-off due to a saturated or frozen substrate, results in the arrival of 'coffee coloured' sediment laden run-off in streams

Fields can be particularly vulnerable to soil erosion where crops such as potatoes, swedes and turnips have been grown in rows. Erosion can be serious where conditions have been wet at harvest and the ground between the rows is rutted. Run-off may then become concentrated between the rows. Soil may also be vulnerable to erosion after row crops are planted when there is a high percentage of bare ground. Crop rotation may lead to different levels of soil protection in different years, and ploughing-in of the crop residue after harvest will improve the organic matter content of the soil. Cultivation of steep slopes, and the compaction of land by heavy machinery also exacerbate erosion problems


Fields next to rivers should not be ploughed before or during winter when erosion is exacerbated by periods of heavy, prolonged rain and flooding. If a crop is sown in late summer or early autumn, e g. winter oil-seed rape or winter barley, there is a good chance that there will be an adequate crop cover to prevent serious winter erosion. Undersowing cereal crops with a grass mixture will mean that there is a good cover of vegetation over the winter after the crop is harvested, which will reduce the potential for erosion.

Direct inputs of sediment can be avoided by leaving buffer strips adjacent to watercourses. The appropriate width for the buffer strip depends upon the nature of the soils, the vegetation and the river. Treatment using fertilisers, insecticides, pesticides and herbicides must avoid buffer strips. Water margins can be an important wildlife habitat, and their value is increased if they are protected by a buffer strip. If there is no buffer strip, there is a danger that the margins will become just a nutrient and sediment sink, and that the diversity of plants will be reduced as the area becomes dominated by plants that can take advantage of these nutrients

Livestock

Trampling by cattle and sheep can compact the soil causing increased run-off. Livestock also trample and feed on vegetation, the root systems of which bind soil together. The destruction of vegetation reduces both the interception of rainfall by plants, and the resistance to run-off created by the plants themselves. This means that more of the rain falling on the land runs off into the watercourse immediately after it has fallen, increasing soil erosion and sediment transport. Heavy grazing of the riparian zone will affect the plant community, reduce shading for fish and perhaps reduce beneficial inputs to the stream

Livestock can break banks down by trampling. They can increase bed roughness by repeatedly crossing the stream at certain points (this locally increases flow height), and they disturb the bed, temporarily increasing suspended sediment concentrations Increased bed roughness and loose soil from trampling, increases the susceptibility of banks to erosion, particularly during flood flows. In addition, the sheer weight of livestock on a heavy saturated bank could cause slumping.

Of course rivers face many more threats with pollution being the instant killer if catastrophic pollutants enter rivers and streams. Other threats include endocrine disrupters. Studies in cells and laboratory animals have shown that EDs can cause adverse biological effects in animals, and low-level exposures may also cause similar effects in human beings. The term endocrine disruptoris often used as synonym for xenohormone although the latter can mean any naturally occurring or artificially produced compound showing hormone-like properties (usually binding to certain hormonal receptors). EDCs in the environment may also be related to reproductive and infertility problems in wildlife and bans and restrictions on their use has been associated with a reduction in health problems and the recovery of some wildlife populations.

When I was a SACG/SAA committee member, fellow committee member Phil Hackett championed a campaign against the use and effects of ED’s and I was one of Phil’s supporters that always thought the use of ED’s would come to haunt angling and wildlife eventually.

Regards,
Lee.
 
Given the extent of the threats, not to mention the mountainous challenges faced when trying to rectify them, the BS or any other singular angling club has no chance of dealing with it. Its simply too big. The Angling Trust, whilst championing the cause of spawning sea bass and sea bass populations, but fail to support our spawning freshwater coarse fish, are also not the organisation to represent our rivers.

Fortunately we already have the Rivers Trusts with other organisations like the Wild Trout Trust and The Salmon and Trout Association who are already on the rivers case. The S&TA have also logged a complaint with the EU regarding the treatment of our nations chalk streams by government.

Regards,

Lee.
 
My dealings with the Angling Trust, discussing their problems with the EA etc. i get the feeling they need the Barbel Society to lobby them, so that they can go and demand answers, they are not Barbel experts, they are an all encompassing body......but I truly believe that if the BS took a case to them they would follow it up.....rather than a series of individuals. The one thing we cant do is accept that there could be a multitude of possibilities and so therefore do nothing, whilst long wordy theories look impressive, you cant beat looking into the white of these peoples eyes and demanding to know what the hell is going on, and if you dont get a response, take it further...sometimes war war is better than jaw jaw...lets take these people on and not be apologists for them.
 
Lee, that really is the most sensible post I've read on this topic, period.

Something with real substance and not clouding the issue with hypotheses of homosexual and diabetic barbel!

Thankyou
 
Rob....I dont think anyone has suggested, that Male Barbel are trying to er....mate with other male Barbel, I think what people are saying including EA and other freshwater biological scientists, is that Barbel and other male fish species are being feminized because the content of sewage effluent, thus effecting their ability to breed .....now if you want to prove them wrong? Was you tongue firmly embedded in your cheek when you wrote that ....lol
 
Cheers Rob. Sorry Lol but I disagree you guys are barking up the wrong tree. I don't know of anyone outside the BS involved in river based organisations who would support the BS theories on this subject. Regards Lee
 
There are many hypotheses and theories, I think in fairness to the Barbel Society and their R&C secretary Pete Reading, and I agree with him, they have not put any reasons forward for the current decline of Barbel on various rivers, however he does say its a complex issue and as I have said I agree, I reiterate the Barbel Society have put no reasons, just possible things that can attribute to poor recruitment, however individual members have put possible reasons forward, some supported by scientific research, the points being put forward have some credibility, so all this is just a discussion in real terms and we all await the outcomes of the future, there is a lot of work being done by individuals and Steve Pope has confirmed that the BS will be instigating a level of research in the coming months, but I am not a spokesperson for them, its only what Steve has told me, the consensus is that Barbel numbers are severely down on some rivers and this needs looking into, one way or the other.
 
Funny thing that Lee. There we were thinking that Professor Charles R Tyler and his huge team of research fellows (Who spent years and millions of pounds in arriving at his internationally praised conclusions) had proven the effect and mechanisms of endocrine disruption chemicals, when he said this.....

A major focus of our research work in EABRG is endocrine disruption, the study of chemicals that alter hormone function which can lead to adverse impacts on health. Our work with colleagues at Brunel University was some of the very first research to show that effluents from wastewater treatment works causes feminisation of male fish, inducing female characteristics including oocytes (developing eggs) in the testis of males. Through controlled, including long term (up to 4 year) exposures, we have subsequently proven that feminisation of wild roach living in UK rivers is caused by exposure to treated sewage effluents. Using a targeted biological screening of chemically fractionated bile from effluent exposed fish, with collaborators (University of Sussex), we have also identified the suite of feminising chemicals in effluent discharges, principally environmental oestrogens, and through laboratory exposures proven they contribute to the feminisation of wild fish in UK rivers. These chemicals include natural and synthetic steroid oestrogens, and alkylphenolic compounds. This original work has been very highly cited. Combining empirical studies with models including Concentration Addition/Joint Independent Action, we have further established that oestrogenic chemicals can be additive in their effects and these findings have had a widespread and international influence. In more recent work we have shown the widespread presence of anti-androgenic chemicals in wastewater effluent discharges and are now studying their possible contribution to the feminisation of fish living in UK rivers.

Just goes to show that you can't trust anyone these days.

Cheers, Dave.
 
Hi Rob,

Thanks for the clarification.

Hi Dave,

Like I said in a previous post, I am an advocate of the effects of ED's and like yourself have read loads on the subject including the Tyler papers among many others. I'm also an advocate in the many other reasons for poor recruitment on some of our rivers as well. The bigger picture is indeed big. In the wider scheme of things however Dave, I suspect only a handful of these issues will ever be fully addressed in my lifetime. As you will know, water is life absolutely. Yet as a species modern humans often give scant regard to its prime importance very often putting money and profit before the very element that provides life on earth.

Regards,

Lee.
 
Hi Rob,

Thanks for the clarification.

Hi Dave,

Like I said in a previous post, I am an advocate of the effects of ED's and like yourself have read loads on the subject including the Tyler papers among many others. I'm also an advocate in the many other reasons for poor recruitment on some of our rivers as well. The bigger picture is indeed big. In the wider scheme of things however Dave, I suspect only a handful of these issues will ever be fully addressed in my lifetime. As you will know, water is life absolutely. Yet as a species modern humans often give scant regard to its prime importance very often putting money and profit before the very element that provides life on earth.


Regards,

Lee.

Hi Lee, I feel sure that your statement "In the wider scheme of things however Dave, I suspect only a handful of these issues will ever be fully addressed in my lifetime" is almost certainly a fact, true for both you and I...which is profoundly sad. Not for us, we have had our day, enjoyed some pretty spectacular fishing because we had the luck to be born when we were. However, unless something fundamentally different occurs in the thinkinking processes of our lords and masters, then things are going to get a whole lot worse before they get better...which is desperately sad for future generations. When the ability of the many multinational corporations to make ever bigger profits is in any way threatened, then governments of all nations fall over themselves to supply the paper and whitewash to cover over the cracks. As you say, even the very essentials of life are not safe.

When the UK government(s) that determine the state that this country will be in in years to come is/are willing to sanction fracking because it MAY provide some income to use as an elastoplast to cover the gaping wounds of years of economic bungling and mismanagement (despite all the dire warnings from abroad about chronic pollution of our underground water reserves), then the scale of the problem begins to emerge. If you add to that the fact that they are determined to spend £60+billion to drive a high speed rail line through some of the finest countryside in the UK....to save 32 minutes on the traveling time between London and Birmingham, then you may think your worst fears have been confirmed (this again despite dire warnings of almost inevitable financial disaster if they go ahead).

It doesn't then take a genius to realise that we are being utterly unrealistic if we harbour any hopes that they might change direction and actually start to care about the state of our rivers any time soon. If something will provide a short term fix to see them through their otherwise doomed political careers, then they will do it, and to hell with any disasters or terrifying consequences that may emerge after they are gone.

Cheers, Dave.
 
Plus none of this is happening on the Trent. We have lots of sewage outfalls with pellet the top bait.
Lee, i suspect the Trent has and still does, received a massive amount of spare Barbel stockies from Calverton over the last 20 years especially with it being so local. I remember Alan Henshaw saying at a B/s show that Barbel fry were the hardiest fry because they came from the egg at 18mm which means they are the biggest of fish fry so have the best chance of survival.What a pity that Calverton is not on the banks of the Colne then my local fishing might have had a future
 
Cheers Rob. Sorry Lol but I disagree you guys are barking up the wrong tree. I don't know of anyone outside the BS involved in river based organisations who would support the BS theories on this subject. Regards Lee

Lee, I totally agree with you.....put the perception of the BS and its influence is significant with outside organisations, I am trying to lobby the BS, so, whilst they may not agree with me and others on the significant and tangible decline of Barbel on a national scale, the very least they should do is support their membership and none member Barbel anglers by challenging those that can make a difference and taking it to the highest level if they dont, if the BS dont, then I and others will, as individuals though I dont think we will carry as much gravitas as the BS....
 
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