Barbel and Nutrition
Fred Crouch takes a look at what he perceives to be one of the main causes of concern in modern barbel angling – overfeeding.
With my angling interest dedicated exclusively to barbel for well over fifty five years I have seen a few changes, but none as worrying as my present concern for our barbel populations. There can be no doubt whatsoever that in the majority of our rivers barbel numbers have dropped dramatically so in this piece I am taking an in-depth look at just what is happening, the cause, and what can be done, if anything, to reverse the decline.
The first thing to say is the reduction in barbel numbers has been accompanied by a rapid escalation of individual weights. Barbel angling history shows there has never been such a comparable leap in sizes.
They were originally confined to three English river systems, the Thames, Great Ouse and the Humber/Trent until throughout the 1900’s many transplants took place and they now inhabit numerous rivers in England and a few in Wales. In 1888 a barbel from the Thames set the official rod-caught record of 14lb 6oz which stood for more than a century, yet such has been the phenomenal increase that barbel of that weight caught today of would hardly cause a raised eyebrow.
As more and more big fish were caught the cause prompted much discussion but unfortunately the truth became clouded by bogus claims; the two most prominent and persistent of which were the barbels’ consumption of high numbers of American Signal Crayfish and increasing water temperatures due to global warming. Hopefully, and at last, both of these notions have been discredited by the following truths.
We are well aware it takes just a tiny number of Signals to find their way into a river for them to rapidly explode into plague-like proportions, a fact that makes a mockery of the suggestion that they were being heavily predated upon by barbel. Anybody that doesn’t accept that should research pre-Signal Crayfish times and they will soon discover that most of our rivers held substantial populations of European White Clawed Crayfish but the growth rate of all Cyprinid species remained at totally natural levels. That is because the amount of digestible tissue in crayfish is extremely small and a huge number would have to be consumed to promote significant growth, but the nail in the coffin of that particular assertion is that barbel have broken many river records on waters that had no Signal Crayfish.
Another claim put forward was that they eat the newly laid eggs of the barbel but as the fish deposit their eggs in purpose dug pits then cover them with a layer of gravel up to three inches in depth they would be out of the reach of the most persistent crayfish, but more about that later.
The claim that global warming has played a part is even more bizarre as our climate has increased by less than one degree in the last decade and only the most regularly targeted river species have shown massive weight gains. If rising water temperature was responsible all species including gudgeon, dace, roach etc would have grown by amounts to break their respective records by equally huge amounts, but they have not.
In a recent issue of a popular angling publication a fish biologist was asked his views on the subject and a couple of his explanations were, to put it nicely, ludicrous. He suggested many fish of today’s inflated weights existed in the past but anglers didn’t have strong enough tackle to land them. I’d say if tackle was strong enough in 1888 to land a barbel of 14lb 6oz from the Thames the odd fish of two or three pounds heavier wouldn’t have been too difficult. Another reason he gave was that scales of years ago were not as accurate as today and very big fish were probably under-weighed. I don’t think so.
Here are a couple of quotes from ‘Understanding Barbel’ which I wrote more than twenty five years ago. “Any river, fished or unfished, will only hold the number of fish which it can support with oxygen and food. If one species begins to increase by virtue of its physical advantage an equivalent decline in other species must occur.” And “How the anglers’ bait affects fish stocks is often completely overlooked.”
I used those lines to illustrate how the stock make-up of regularly fished areas is heavily influenced by the nourishment provided by anglers. Stretches most popular with anglers are normally closest to parking facilities and soon become those most favoured by fish and before too long the extra food provided falsely inflates fish numbers, which then become acutely dependent on the anglers’ provisions.
There are glaring examples of this symbiosis across the land although it may not be immediately recognised. Lack of fish in any stretch of river have often been blamed on the river itself because as anglers we are more familiar with inflated fish stocks and when faced with much reduced numbers living on what nature provides we are mistakenly tempted to focus on the river environment as a cause of something amiss. Here is a perfect example:
The dense, healthy fish populations of the historically famous Royalty Fishery on the River Avon at Christchurch have been attracting anglers for well over a century but anybody that believes that is purely by virtue of the fertile chalk river may be surprised to discover just above the top weir the same river is devoid of anglers - and virtually devoid of fish. Rivers that don’t benefit from a regular supply of extra food will only support a modest natural fish biomass and that can be unbelievably small. It is a mistake to think that stock numbers on a regularly fished section of river is in any way representative of the river as a whole.
A perfect example of just what impact different baits can have on barbel populations occurred on the Royalty back in the 1970’s. From the start of the 1972 season maggots were banned on the fishery after almost fifteen years of heavy use. During the whole of that time the barbels’ weight remained within the normal parameters with the upper weight limit under twelve pounds. Catches were generally made up with fish between three and eight pounds even though hundreds of gallons of maggots were fed into the water every week. The fish could, and did, gorge on them all day long because the amount and calorific value of digestible material contained within the larvae is small.
A noticeable change took place after 1972 when most Royalty anglers began using luncheon meat as an alternative to the outlawed maggot. Within a few seasons one or two barbel reached 12lb and it soon became clear the massive amount of luncheon meat finding its way into the fishery was having an effect on weights. It must be understood that many anglers used the rolling meat method with large hook-baits which were often dislodged from the hook by weed or missed bites and many attractor lumps were thrown in and it is not an exaggeration to say dozens of tins went into the water every day.
True, mixed river fisheries attract various angling styles and all species get a share of the anglers’ baits but as they gain in popularity the barbel are gifted an advantage in as much that the donation from the angler is presented in a way most likely to benefit the bottom feeder and because lesser species are naturally reluctant to compete with much bigger fish the barbel soon begin to dominate. The only species that can challenge the barbels’ dominance is the odd carp providing they are of comparable size to the barbel so it is safe to say that the barbel has virtual carte blanche where available food is concerned especially when it in the form of large pieces or is spread on the bottom. The net result of that scenario is that lesser species decline in numbers to make way for the increase in barbel which is reflects nature’s balancing act.
Now let’s take the angler out of the equation for a minute or two and have a closer look at how, left to its own devices, the barbel fends for itself. In its natural undisturbed environment it will spend roughly four to six hours per day, normally shared between dawn and twilight, in all but the coldest periods seeking out whatever creatures are abiding in and around the stony river bed. They have to work hard using lots of energy gleaning what provides just a little more than a maintenance diet in the mature fish but that’s all they need to do because the rest of their time is spent at rest. They will extend their feeding time to support their fast growth period - the first four or five years of their life - after which the growth of the males slows, while the females continue to grow at the same rate, a process called sexual dimorphism.
Nature, left to its own devices doesn’t allow for ‘overweight’ in animal species because of the negative effect on mobility, general life-style, longevity and ability to reproduce. The only time any creature grows to obese proportions is when man interrupts this evolved balance and we do so at our peril because evolution normally gets things right, bringing order to the natural world, but man often get things seriously wrong, bringing chaos. With pets, the correct amount of food and exercise is essential to ensure their stature stays within the parameters for good health but some owners ignore the expert advice and the outcome is normally an obese and uncomfortable creature.
We, as humans, are constantly being warned about the dangers of obesity and informed of the cause. It is surely the easiest example of cause and effect we could ever have. If any creature ingests more energy in the form of nutrition than they expend the result will be weight gain. The fish in our rivers don’t grow to monstrous proportions when left to feed as nature intended and if it happens is because they have been overfed with huge amounts of high nutrition food.
It has to be cruel to overfeed any creature to the extent their well-being is impaired but one overlooked element of obesity is that once it occurs the body demands extra food to fuel the extra size and that’s where the real difficulty lies. More and more humans are overriding the guidance they are offered to limit food to healthy levels but at least they can get appropriate advice but lesser animals don’t so they can pay a heavy price when their natural feeding regimes are altered to yield nourishment at far higher levels than nature ever would.
We are all now well aware that obesity effects general demeanour and can massively reduce life expectancy and no-one can deny that barbel, misshapen by being grossly overweight will find resisting a heavy flow more exhausting than if they maintained their natural shape. This becomes clearly obvious when playing the heavyweights as they ponderously labour against strong flows and cannot match the speed of lighter, slimmer fish without a massive increase in energy output which will place huge physiological strain on every part of their bodies which could mean an earlier death than otherwise expected.
Make no mistake, high nutrition food was developed decades ago for maximum growth in animal farming so we shouldn’t be surprised when it has exactly the same effect on barbel. Next time you see on television the captive, hand-reared salmon in Scotland being fed with just a few handfuls of pellets remember there is a huge number of growing fish in any cage yet I have seen anglers arrive at the river with a bucket full of pellets and leave with it empty! It is not the food itself but the grotesque amounts used that is encouraging barbel and other cyprinids to grow to unhealthy proportions. Our barbel evolved a hydrodynamic shape suited to fast flowing rivers but it isn’t evolution that has caused such a gross distortion of that shape, it is the angler with the careless use of high powered bait!
A little understanding of the barbels’ anatomy illustrates perfectly why nutrient-rich foodstuff has such a potent outcome. They have a relatively poor digestive system consisting of throat teeth that tear, no true stomach, and an intestine not much more than the overall length of the fish. They maximise their nutritional intake by eating whole insects and other roughage which have a substantial amount of indigestible content to create a ‘pestle and mortar’ action to break down the soft tissue.
Compare that to the human who has a comprehensive set of teeth to cut, grind and crush food which begins to digestive in the mouth then moves into a stomach that continually squashes and liquidises it until it enters a thirty feet long digestive tract where most nutrients are removed.
By feeding high nutrition food to barbel their physiologically balanced system is overridden because the ingredients immediately break down into easily absorbed nutrients. Add to that the effortless way it is gathered and the result is all too obvious. We all know that when animals, including us, were fed an excess of high powered food while expending very little energy the result is rapid weight gain.
There are three more facts that underline the barbels’ limited need of nutrients.
1. Whereas warm-bloodied land animals expend energy to maintain their vital body temperature but cold-bloodied fish is regulated by the water itself.
2. Unlike land animals, fish do not need to use energy by constantly opposing the force of gravity as their swim bladder renders them neutrally buoyant.
3. During severely cold weather they can rest and go without food for several weeks on end with no ill effect.
The successful procreation of barbel is a one of the wonders of nature especially considering the critical factors that have to be met if spawning is to be fruitful. The gravel has to be made up with exactly the right sized stones to allow for correct percolation of oxygen bearing water. Any clogging of the interstices, they are the gaps in between the individual stones, would quickly bring about a lethal drop in vital oxygen levels. The water temperature has to remain between 14 and 18 degrees centigrade, the depth has to remain constant, as does the water velocity which facilitates oxygen needs and the female has only forty eight hours to shed the eggs once they are mature.
If the fish get all the right conditions it would stand for nothing if one other vital element is not achievable and that is the successful shedding of the eggs by the female and that is why, as I will explain, the optimum water velocity is so important.
Barbel eggs differ from the eggs of other Cyprinid species inasmuch as they have very little or no adhesion on the outside membrane, called the chorion, which makes the placement of them critical if they are to be viable. The male barbel is normally sexually mature at the age of two or maybe three years but the female isn’t until she is eight or even nine years old. At that age under natural condition she may be six or seven pounds but ingesting high nutrition food over a number of years could elevate this to double figures. The difference between naturally being 10 or 11 pounds and being the same weight through over-eating is telling by comparison. Instead of having a long, slim body the female will be very stocky but shorter and that could pose her a tremendous problem.
Because of the lack of adhesion the female has ‘trap’ the eggs by covering them with stones. This is done by digging a pit with her tail least three or four inches deep then squirting the eggs into it while immediately covering them by sweeping the stones back.
Now here is the problem. To carry out that manoeuvre and accommodate the male as he sheds his milt onto the eggs she has to arch her body up to an angle of 30 to 45 degrees. An over-stocky stature may make it virtually impossible for her to achieve this posture and hold it against the flow making it highly unlikely that the eggs would be deposited in the right place and be secured by a covering with stones. Eggs left exposed would be swept away in the flow to be eaten by all and sundry. As all very big barbel are females we have unwittingly created a huge obstacle to successful recruitment.
We know for a fact that where anglers are excessively using high nutrition baits numbers of fish have dropped alarmingly as individuals have grown to monumental proportions. Rivers that I am extremely familiar with no longer produce catches of anything like the numbers they did a decade ago and I would be surprised if any members’ mature local waters show a different situation. I use the term mature because rivers like the Wye are young in terms of barbel stocks and yet to reach their potential but as they do, and if anglers’ baiting habits don’t change, they are certain to follow suit.
Am I just scaremongering? No I certainly am not. My local river, the Lee, used to hold large numbers of barbel throughout most of its upper and middle reaches. It never threatened the rod caught record with double figure barbel the exception and fish between 2lb and 5lb most common but over the last decade the change has been worrying. In the middle reaches individual weights have spiralled to 17lb plus which might sound really good until you factor in the accompanying decline in fish numbers which are now only a small fraction of what they used to be. In most of the upper reaches it is as if time has stood still and a 10lb fish is still a monster but it is possible to hook barbel of less than a 1lb up through every weight class and the reason is in most stretches the over-use of high nutrition baits is still rare.
It seems to me that the practice of loosefeeding either by swimfeeder or bait dropper which was always so popular to get good amounts of particles such as maggots, casters, sweetcorn, chopped up luncheon meat and hempseed onto the gravel bed has been maintained with pellets etc. The big problem is that their nutrient value is far more powerful than the previous favourites and clearly if things don’t change our barbel stocks will continue to dwindle.
My personal message is for those that choose to use the baits in question to please keep the loosefeed to an absolute minimum and help encourage our barbel stocks to recover to more natural levels. I know, from the many anglers I have asked, the vast majority would love to go back to fishing for fun. Who wouldn’t enjoy going to their favourite river and catching several fish up to 7 or 8lb with half a chance of a double? To prove my point I would highlight the rising popularity of the River Wye which I honestly believe is soon to become the centre of barbel angling and most fished rivers in the land and yet at the moment there is very little chance of a monster.
We must all accept that holding the record nowadays is pretty well irrelevant and totally false encouraging the practice of intentionally targeting and overfeeding small groups of fish in an effort to create another record. The majority of us are disturbed at the threat to our fish stocks imposed by an increasing otter population. Bear in mind if we continually reduce our barbel numbers by increasing the size of individual fish we create further problems. Big fish are unlikely to out-swim the otter which makes them far more vulnerable and because barbel numbers must decline in keeping the biomass balance when we do lose one to an otter it is obviously a greater percentage of that biomass than a smaller fish would be.
Remember, we can have a large number of smaller fish or a much reduced number of very big ones but unfortunately we can’t have both. Getting the future life-blood of our sport, the youngsters of today, into barbel fishing, is being made much more difficult than it need be because they like to see a bit of action and for that we need more fish not less.
That’s all for, I’m off to the upper Lee for a bit of fun!
This feature, with the exception of the FishingMagic images, was first published in the Barbel Society members’ magazine ‘Barbel Fisher’ and is reproduced here by kind permission of the Society and the author.