Archive for March, 2016

Weighting for Godot

March 29, 2016


Are lead underbodies worth the effort?

I remember a story from years back where a young girl asked her mother “why”, whilst she was preparing for Christmas lunch, “do you cut the gammon in half before cooking it Mommy?”

The mother said that she had learned to cook it like this from her mother, the child’s grandmother but they would ask granny when she came to lunch.

So at lunch the mother asked Granny (her mother) , “Mom, why does one cut a gammon in half before cooking it?”, to which she replied that she had learned to do that from her mother.

Now as luck, or good genes ,would have it ,the great grandmother was still extant and off to then nursing home the family trotted, it was Christmas after all, and asked of the Great Grandmother the same question. “Why does one cut a gammon in half when you cook it?”, to which the all too pragmatic response was “When I was first married we didn’t have a pot large enough to fit in a whole gammon”.



That story brings up a very interesting question: how many things do we do just because we were taught to do them that way, and do they actually make any sense, or is it simply a case of doing things in a way which we always have?

I would put it to you that adding lead underwire bodies to tungsten bead nymphs, something that one can watch in numerous video clips and read about in hundreds of fly tying books might be a waste of time. In fact if you don’t understand exactly what you are doing and why you are doing it, counter- productive even..

WaltsWormA post about “Walt’s Worm” got the juices flowing but it is a common question about many
“Bead Head” fly patterns.

This is dangerous stuff because I recently looked at a post about a fly called “Walt’s Worm”, nothing bad about the worm, a basic hare’s ear nymph, re-branded by Walt because he had added a bead to it and ditched the tail. Nice fly, pretty in a buggy sort of way, and certainly a fish catcher I don’t doubt. Then came the instructions and “recipe”, including an under-body of lead wire and my synapses started to fire. As I said, dangerous stuff, my head can be a wondrous if confusing space and my mathematics are questionable at best, but it had me all abuzz because I question the logic, “Does bulking out the fly with lead wire make any sense?”.

Out with the calculator, the computer, and references to long forgotten formulae, to ask myself the question; “What is the real difference between a Walt’s worm (or any other subsurface fly pattern for that matter), with or without the lead wire?

I wound ten turns of 0.5mm lead wire around a size 10 Grip jig hook and then unwound it again to measure the length. 35 mm or close to it.

How much would that amount of wire weigh?

The volume of a cylinder (in this case wire) is calculated using the formula   πr2L Where π  is taken as 3.1416 and r is the radius of the cylinder whilst L is the length of the wire.

So a piece of 0.5 mm wire 35 mm long has a volume of :

3.1416 x .252 x 35 = 6.87 cubic mm.

The density of lead (per Wiki), is 11.3 grams (approx) per cubic cm and there are a thousand cubic mm in a cubic cm.

So the mass of our piece of wire is 11.3 x (6.87/1000) = 0.0777 grams..

Wonderful so we will have added near eight hundredths of a gram to our fly by this time consuming process of laboriously wrapping lead around the hook. We will, as shall been seen later also vastly increased its diameter and therefore volume when dressed.


What about Walt’s pink tungsten bead?

Let’s assume that we choose to use a 3mm Tungsten Bead and here come those questionable maths again.

The volume of a sphere (in this case the bead) is given as    4/3 x π r3

Which would give our 3mm tungsten bead a volume of:  4/3 x 3.1416 x (1.5)3

A volume then of 14.14 cubic mm, or 0.01414 cubic centimetres.

The given density of pure tungsten is 19.3 g per cubic centimeter

So our bead weighs 0.273 grams.

Put into perspective that is 3.5 times as much as our fiddly little piece of wire.

But I cheated because the bead had a hole in it, approximately 1 mm going through the middle.

So actually the volume would be 14.4 cubic mm less the volume of the hole , out with the cylinder maths again. The 1 mm diameter (0.5 mm radius) hole has a volume of approximately 3.1416 x 0.52 x 3.
(based on the equation πr2L again). Which equals 2.36 cubic mm or 0.00236 cubic centimeters.

So our bead really only has a volume of 14.14-2.36 cubic mm or 11.78 cubic mm or .01178 cubic cm and a real mass then of 0.01178 x 19.3 grams… 0.227 grams. (Still approximately three times more than the lead)


Why add the lead then? It does add a bit more mass to be sure but if you only used a 3.2mm Tungsten bead instead you would end up with a mass close to the total of wire and bead in the previous example,  (and I am going to suggest that you forego the maths and ask that you trust me).

Volume of 3.2mm bead,  17.16 cubic mm less the hole (2.51 cubic mm) = 14.65 cubic mm or 0.0146 cubic centimetres and therefore a mass of 0.28 grams.

In the above leaded example the total mass added was 0.227 plus 0.0777 = 0.3047 grams (0.0217 grams more but potentially a lot more bulky than the bead only version).

If you choose to use a 3.5mm bead instead the total mass without the lead would be:

Volume of bead = 22.45, less volume of hole  ( 2.75 cubic mm = 19.7 cubic mm or 0.0197 cubic centimetres with a mass of 0.0197 x 19.3 = 0.380 grams.

Remember the total added weight to our Walt’s worm with the wire and bead combined was 0.3047 grams. WOW just by adding a 3.5 mm bead instead of the 3.0 mm bead we have achieved a huge improvement in the mass and of course because of the lack of the lead underbody have a far slimmer fly which will sink faster. Not only because it has more mass but because of the greater weight and lesser volume we have far greater density too. It is worth bearing in mind that a small increase in diameter of a bead makes a massive difference in the volume and thus the mass.

Now that was a very long and arduous (at least for me) means of showing that this “following the instructions” without thinking about the consequences style of fly tying puts us right up there with the people with small pots and chopped up gammon.

Sure if you want a more bulky fly, it would be better to use lead wire under the body than something lighter like thread or more dubbing. But if you want to get a quantum leap in terms of mass and density using a fractionally larger bead is the business and a whole lot faster to manufacture.


(Gary Glen-Young pointed out, and I agree, that if your aim is a more bulky fly then having a lead wire under-body is far better than having a thread under-body. So if profile is important then adding lead is a good idea, but if the lead is added as additional mass only , without the intention of increasing cross sectional diameter it is counter-productive because it equally increases the bulk of the dressing for little gain in mass.

In other words, if you need to use something to bulk out the profile of the fly then lead wire is a good choice where sink rate is a consideration. However ,if you don’t need the bulk, then you are far better off to leave the lead out, keep the profile slim, get the mass from the bead and avoid the wasted time of winding wire.

In general , these sorts of discussions amongst anglers and fly tyers are not about weight (even if they think they are), in fact they aren’t really about density either, they are about the all too practical applications of sink rate. Adding mass is great but when that also increases the volume of the dressing then it can become rapidly counter- productive.

BeadsLead.fwIncreasing the diameter with wire, and then dubbing over that increased volume, may very well negate the benefits of more mass in terms of the sink rate of the fly.

These days I add weight to flies almost exclusively with tungsten beads, sometimes tiny ones, but it is a more effective means of achieving the desired goal and adding a little bit of lead to the shank of the hook is doing little to improve the fishability of the fly. It might please you, make you feel that you are a better fly tyer and are following “the way it should be done” more accurately. But unless you are using the lead to build a profile shape, I assure you that you are wasting valuable time for no good reason.

Certainly, there are other considerations when tying flies, and some nymphs you don’t want to plummet to the bottom. One might require different profiles, or movement in the water. However, a tungsten bead fly on a jig hook really spells “sink fast” and if that is the point, some consideration as to how best to achieve your goal is worth it.

Special thanks to Gary Glen-Young, the “go to guy” when it comes to maths and fly fishing, whose synapses fire on a far higher plane than mine and who was kind enough to check , and I have to admit on occasion “correct” my woeful mathematics.

As always comments are most welcome.





What’s on your plate?

March 17, 2016


Some thoughts on our responsibilities as both anglers and people in making sustainable choices.


I can recall fishing as a youngster in the local canal, a waterway that contained all manner of fish species. Carp, Tench, Rudd, Roach, Perch, Bream etc .There I was, rod in hand, a bait of bread paste dangling under a bright orange tipped float, waiting with “anxious anticipation” for the float to dip indicating a bite.

FishingFloatThe simple joys of fishing or eating fish are dependent upon us all
behaving in a sustainable manner.


A gentleman walking his dog along the side of the canal and obviously in gregarious and cheerful early morning spirit enquired “what are you fishing for? “ to which I replied, (I thought rather cleverly at the time)…..”Fish”.


Of course I now know that you can “predict” to a fair degree what species you catch depending on what bait, set up and location you choose. That in short, fishing, isn’t quite the lucky dip process that I thought it to be as a small child.

Many anglers can tell what fish they have on the line well before actually seeing it, the fight of a grayling and a trout are notably different, the speed of a skipjack, easily distinguishes it from the initial run of a leerfish. Odd then perhaps that although we can tell what fish we are likely to catch, before the line ever goes tight, and more so that we can tell what is on the line before we actually see it , it is a concern that most of us can’t tell what fish is on our plate.

Truth be told it isn’t entirely our own fault, people have been fibbing about fish for as long as they have sold them for food. Back in the day, my local fish and chip shop sold “Rock Salmon”. There is of course no such thing and Rock Salmon, turns out, actually, to be dogfish, a small shark. Vendors quickly realized that “Rock Salmon” sounds a lot more palatable than “Fried Shark”. Covered in batter and served up with a plate of chips who’s to know, or even care for that matter?

OrangeRoughyThe Orange Roughy is estimated to live for up to 150 years, it is slow growing and late to mature, discovery of this resource was almost immediately followed by over fishing and collapse of many populations.

Chilean Sea Bass, (another entirely fictional name created by the marketing department to make it sound better), turns out to be Patagonian Toothfish, whilst Orange Roughy, the poster child of unsustainable fishing practice still gets flogged off as “Deep Sea Perch”. The name carefully selected, because most of us know that you shouldn’t be eating a fish that could be 150 years old, and one that due to slow growth and breeding make it extremely vulnerable to overfishing. You might be amazed, as was I, at how many recipes there are on line for Orange Roughy. It is a bit like having recipes for poached Dodo or Grilled Galapagos Tortoise freely available, although at least in this instance people are being honest. Trouble is that many are not and what you get on your plate may very well not be what you thought it was.

So the first question then is: “Why would it matter?”. I mean if your “buttered hake starter” isn’t what it said but it tastes nice, who really cares? The answer in short is that you should care, not because of any effect on your culinary enjoyment, but because, as I was to discover as a child, a fish is not just a fish, not all fish are equal and not all methods of catching them are equal either.

In a world which desperately needs to focus more on sustainability; eating an Orange Roughy snuffs out a lifespan potentially twice as long as yours, and the breeding potential that goes with it. Eating a sardine probably doesn’t do a lot of harm.

Put into perspective, most people would be pretty upset if they found out that their filet mignon was actually banded armadillo, so why not be concerned about the fish that you eat?

There have been initiatives around the world to better inform consumers of what fish they should and shouldn’t eat. Such as the SASSI (South African Sustainable Seafood Initiative) lists which delineate fish types based on the sustainability of both the resource and the method of capture.


You can download a copy of the SASSI Card here

You will also find a useful and FREE cellphone app to help you select sustainable seafood choices, just search SASSI on your preferred App Store.

Sustainability isn’t simply about fish stocks and breeding rates, but also about damaging by-catch, environmentally destructive fishing practices, and much more. Even farmed fish may very well be causing damage to the oceans as a result of depletion of food resources harvested to make “fish pellets”. It isn’t simply a question of what fish you eat, but how they were caught, what they were fed, and even where they were captured.

BycatchSustainability isn’t just a case of the fish stocks but also the fishing methods, the negative affects of by-catch being one of many parameters to consider.

By the way “By-catch” is a nice sanitized euphemism (rather like “friendly fire”, or “quantitative easing”) for the destruction of unwanted species, fish , mammals and birds, as part of the fishing process. Turtles, Dolphins, and countless unwanted or undersized fish are slaughtered as a result of some fishing methods, which means that even if the targeted fish stocks are sustainable the fishing methods are not.

It is becoming increasingly obvious that the web of life and the interconnections between various aquatic fauna and flora are far more complicated and interrelated than was once imagined. But people are becoming more aware, which is good. What isn’t good is that with your new found knowledge you are still at the mercy of the unscrupulous if you can’t tell what is on your plate.


The Marine Stewardship Council is a seafood certification and eco-labelling non profit organization aiming to label seafood such that consumer confidence in what is actually part of your dinner is enhanced. In effect tracing seafood from point of capture to your plate. On Wednesday they launched a campaign to raise awareness of “Seafood Fraud” , urging consumers to ask questions as to the origin of their seafood. Questions we all need to ask and understand.

It is estimated that world wide some 30% of all seafood is mislabeled, but DNA testing of MSC certified seafood showed a 99% correlation, proving that careful monitoring insures that you get what it says on the packet. We have seen a number of food fraud scares of late, horse meat being flogged off as beef and such, most of the outrage more about people’s attitudes towards consuming one species but not another rather than anything to do with sustainability. With seafood the fraud has more far reaching consequences. Supporting unsustainable fishing practices may very well contribute to the ultimate destruction of the oceans and with that the destruction of ourselves. Checking that what seafood you consume is, indeed, what it says it is, is a step in the right direction towards protecting our planet and the animals which share it with us.


South African Hake Trawling: a sustainability success story:


Marine Stewardship Council

SASSI (South African Sustainable Seafood Initiative)

SASSI List for consumers. Check the status of your seafood

MSC educational resources for kids. Teach your children about sustainable seafood.



Don’t forget to look out for the MSC “fish tick” label that tells you the fish have been harvested in the most environmentally sustainable manner.

Vulnerability, A super stimulus?

March 7, 2016



Is frailty a key trigger for trout?

Sometime back I published a post “The Cuckoo and the Trout” based on the genetic considerations of “super stimuli” as discussed in Richard Dawkin’s exceptional book “The selfish Gene”..
The basic premise being that some stimuli override other considerations such that in this instance a tiny parent wren “ignores” the obvious fact that its parasitical baby is far larger than makes sense.

I think that the concept that some stimuli override other considerations might go a long way to explain some of the rather perverse considerations of fly tying and fly fishing. Why would a trout ignore the hook sticking out of a fly or the tippet tied to its head? And why would it make sense to make close copy imitations of bugs when we all know too well that the best efforts are going to be let down by these necessary limitations of design?

Certainly I know anglers from the States who claim that the bodies of their PMD’s need to be a little more red on the upper reaches of a particular stream and a little more yellow lower down. They will swear on the Bible this is true and I have no reason to doubt their assertions, but surely it is daft to consider such a minor variation of import when the trout can easily see the hook sticking out of the imitation.

Could one suggest that some factors override others when making an assessment and that we all do this at one level or another. It is a case of simplified abductive reasoning “if it looks like a duck, swims like a duck and quacks like a duck, it most probably is a duck”.(I could add: even if there is a hook sticking out of its bum)

For animals, including ourselves, to operate in a complex and ever changing world we cannot in reality assess every possible piece of information available before making a decision, and for a predator, such as a trout, the window of opportunity to make a decision as to “eat it or not eat it” is limited before the potential prey item has been whisked away by the current or flies out of reach.

In reality then one need not actually undertake any cognitive gymnastics to be able to come up with a quick strategy in terms of assessing information. General rules which hold true most of the time will suffice.

A Lion on the plains of the Serengetti, need not consider why a particular Wildebeest is slow or limping, it only need recognize that a slow or limping prey animal is a better bet requiring less effort and smaller risk in terms its capture. So I would suggest much the same holds true for trout in a stream.

Firstly we all recognize that it is on average much easier to deceive fish in faster flowing currents, they have less time to make the decision; I would suggest that every fly angler across the world recognizes this simple truth. I would then further hypothesize that the less time available the more one relies on key information.

So of all the information available to a fish to assess the validity of a potential food item the less time it has to make that decision the fewer bits of information it can use to reach a conclusion

In this, admittedly arbitrary, diagram below, the idea is that of all the possible clues to the validity of selecting a potential food item as real some will take precedence depending on the amount of time available. i.e. Faster currents allow for less time. Not to mention previous positive and negative experiences of the fish.

AssessmentOf all the possible considerations in assessing potential food items how many does a fish actually use and is it possible to induce a shortcut?

If this were true one would expect that the faster the water the less specific one’s imitation would have to be and even the less important the presentation, this would seem to be borne out by much on stream experience.

So what if one could “beat the system”? What if even when the fish had all the time in the world we could find a way to shortcut the selection process and increase our chances of deception?

Obviously one might expect that plenty of other factors , some of which we can’t imagine are potentially at play. To hypothesize further then, one might expect that the more hungry the fish the more likely it would be to make an erroneous snap decision. Equally where there is a massive opportunity of lots of food in a short time, (The classic duffer’s fortnight of Ephemera Danica on the English Chalkstreams for example), the fish may be rather more “Gung-Ho” than normal. It is perhaps equally worthy of consideration that most of the time in nature an erroneous assessment isn’t overly problematic to the fish, a waste of a little energy and spit out the offending item. It is only the machinations of the angler which make an erroneous selection potentially fatal or at best inconvenient.

It strikes me that one of the significant triggers to predatory behavior is apparent vulnerability, the lions on the Serengetti sitting about under a tree, chilling in the afternoon sun; but should a limping Wildebeest wander past the whole game changes and predatory instincts kick in. The pack is on the hunt, keyed into the possibility of easy prey.

I would suggest that using the same logic it is possible, at least some of the time, to trigger that response in fish with the arrival of an apparently easily captured food item.

In a human context perhaps much the same applies when hunting (read shopping in the modern world). Yes you can research the presence of GMOs in your food, the number of calories, whether it is halal slaughtered, the sell by date and much more information all of which is readily available. But do you? And more to the point even if you are more than averagely pedantic can the offer of a bargain,” two for the price of one”,” 10% off” etc shortcut your normally extensive analysis? I would suggest that it can and that the marketing departments of most food companies fully understand that.

What would happen to our supposed decision time-line were we to add in some super stimulus, the piscatorial equivalent of “A Bargain”? Such as apparent vulnerability? After all to a predator, an easy meal is in effect a bargain, less costly in terms of effort and risk, could that result in the bypassing of normal selectivity?

Is it not likely that with the bonus of apparently “easy prey” the decision making process could be short cut, a snap decision induced in the fish?

VulnerabilityCould the trigger of an apparently easy meal short-cut the process of selection and result in more effective fly pattern?

In a recently observed example I was guiding a couple and the one angler had opportunity to cast over a clearly visible fish, not feeding overly actively but quietly taking the odd nymph or surface fly. This all in slow moving clear water (The worst case scenario for an angler in general). Casting small dries, nymphs and even more weighted nymphs elicited no response and it seemed as though the fish may have become aware of our presence. Then a cast of a diminutive and very simple soft hackle pattern, presented apparently helpless in the film. A non specific morsel that undoubtedly looked a bit worse for wear. The fly landed a fraction to the side and slightly behind the fish, it turned and ate the fly with knee jerk aggression. This after better presentations of far more perfectly constructed flies. Could it be that the “vulnerability” of the pattern was the key?

I would suggest that this and other “super stimuli” might equally short cut the decision making process (not for a moment implying that there is any great deal of cognitive behavior on the part of the fish). Most of us would accept that a negative super stimulus, for example drag on a dry fly or a splash on presentation would result in a shortcut, this time a negative selection, so why not a positive shortcut if we get the stimulus right?

Add in something that the fish particularly likes, say an Ant pattern. It is well known that trout LOVE ants and their response to ant patterns is frequently nonsensical, they expend more energy and move further to capture an ant pattern than they do other food items, real or fake. Could it be that the super stimulus of a segmented body and recollection of pleasant taste override the normal selection process? It is certainly worth a thought.

The ideas discussed here were mostly driven by a desire to consider why should very simple soft hackle patterns be so effective. Soft hackles, North Country Spiders, Emergers, Stillborns and such all lack much in terms of actual imitation but do offer up the illusion of vulnerability and/or chances of escape (in the case of emergers). Could it be that these patterns work as well as they do because they provide a triggered shortcut to the normal food selection process?

I don’t know what or even if a trout thinks, I do know that they do some things that don’t on the face of it make sense, but I would suggest that viewing their behavior in the light of this hypothesis does potentially offer some explanation.

Some examples:

The current is fast and on average the fish are less critical of fly and presentation. (decision process limited by available time).

Fish slash and burn energy during rapid emergence of caddis flies… (decision process pre-empted by the lack of time due to potential escape of the prey).

Fish in slow flat water are difficult to fool, (few limitations on the decision making process, plenty of time and increased visibility of the fly, the hook, the tippet and even the angler.)

Significant hatch of large flies (Ephemera Danica): Increased gain of calories at low effort, repetitive reinforcement of decision making (other flies have been fine to eat), limited time to make the most of the windfall.. short cut decision making and eat as much as possible..

Wild fish in remote spots: On average have never had a negative consequence and as such will eat almost anything. No evolutionary pressure to be more selective.

Fish in heavily fished Catch and Release waters, a history of negative consequences for poor decision making. More evolutionary pressure to be increasingly careful, fish more difficult to deceive.

The classic, “induced take”. Is the decision making process short-cut through the apparent risk of escape of a food item?

The overly large fly, could it be that the promise of very high calorie food easily obtained can circumvent the normal selection process and induce a snap decision from the fish?

I think that in all of these examples there is enough subjective evidence to suggest that much of the time this hypothesis holds true and that the angler can use this to become more effective at deceiving his quarry.

I would suggest that in most of the cases I can consider the idea that the decision making process is varied and that thinking in these terms many apparently aberrant behaviors could have a logical explanation. It also suggests that “exact copy” fly tying may well be one of the least effective strategies for the angler.

Something worth thinking about ?


If you enjoyed this piece you may like other articles and books by the same author available on line:



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