I have always considered fly lines to be the unsung heros of fly fishing. They will arguably (and perhaps even incontrovertibly) receive more abuse and neglect than any other piece of fly fishing tackle, but they still rarely “complain”.
Fly lines aren’t considered “glamourous” by many anglers, so they aren’t (typically) highly coveted, drooled over, or collected like rods and reels are. Often they are simply relegated to being a functional piece of equipment we’d rather not spend much money on. Think about it, when was the last time you saw someone posting pictures of their newly acquired fly line, and had a fly fisherman say something like, “Congratulations on the new Orvis Wonderline! It’s a real beauty!”
Nope, a fly line gets little respect, and yet it contributes so much to our enjoyment of this pastime. And when it comes to the lighter line weights, there is even less respect to go around. For example, consider the oft heard statement:
Using a line too light for the intended quarry puts undue stress on the fish and increases the mortality rate.
Now this statement (or something similar) is generally made in reference to sub-four-weight lines, and more times than not is specifically made in reference to fly lines or rods rated lighter than a 3 weight. The premise or precursor to this is the belief of the individual that a lighter line is unable to handle the stress and strain of a large fish without breaking. Therefore, the angler will have to play the fish to the point of complete exhaustion before it can be brought to hand. There is also the assumption that if a heavier line weight was being used, the angler could more easily just drag the fish in before it was completely played out. Thus heavier line weights are more ethically responsible in caring for the fish that are being targeted. This certainly sounds reasonable enough, and my impression is that many anglers accept this type of statement without truly thinking it through.
The issue I have with this statement (or one like it) is that I can find no data to support it (only opinions). My own experience, and the facts associated with fly lines (ultralight lines or otherwise) lead me to believe that it simply isn’t true.
For example, we know that a 1 weight Rio Trout LT line, and a 6 weight Rio Trout LT line have the very same core material. Since the core material of the line is what provides the tensile strength for it, the tensile strength of both of these line weights is going to be (for all practical purposes) exactly the same. This is not a Rio specific manufacturing process either. Pick a product line, and you’ll find that every sub-7 line weight within that series will share the exact same core material. There may be an obscure exception somewhere, but I couldn’t find one.
Now it doesn’t take much intelligence to understand that if the various line weights have the same breaking strength, you can’t pull harder with one than the other. And that is a fact, not an opinion. So take your pick and pull away.
The lone exception to this scenario is a silk line. So if you are a die hard silk line fisherman, and the individual you are talking to is only using silk lines as well, you may have a leg to stand on. Being that silk lines do not have a plastic coating to create the taper or add weight to the line, the taper or additional weight must be created by weaving in additional strands of silk. This will of course add density and/or thickness to the line, both of which will also add strength. So if the thinnest section (tip) of a heavier weight silk line is thicker or more densely woven than the thinnest section (tip) of a lighter weight silk line, then one can reasonably assume that it will also be stronger. Therefore, you should be able to pull harder with a 6 weight silk line than with a 1 weight silk line without the line breaking.
In reality, irregardless of whether an angler is using a silk line or a plastic coated one, the tippet (or a knot) will likely be the weakest point in the angler to fish connection, and the angler won’t be able to pull any harder than the tensile strength of that weaker element. So the fly line’s actual tensile strength will probably become a moot point. The point that will remain though, is the fact that you won’t be able to pull any harder with a 6 weight line than you would be able to with a 1 weight line in bringing the fish quickly to hand.
There’s another part to this issue though that is certainly line related, but not the actual line. The premise here is that the rod is the limiting factor, and that it will determine the angler’s ability to bring the fish quickly to hand. The point being that using a rod designed to cast a light 1 weight line doesn’t provide the angler with the backbone strength in the butt section of the rod to fight a strong fish like a rod designed to cast a hefty 6 weight will.
I’ll gladly concede this point, but I would also like to point out that if the goal is to bring the fish quickly to hand and not “fight” the fish, one can “point” the rod at the fish and effectively take the rod completely out of the equation. One need look no further than the many world cultures that bring fish to hand using nothing more than a hand-line to understand this concept. And that includes catching some very large sea dwelling fish. So don’t believe for a moment that you need a rod to haul in a fish. It can certainly help, and is arguably more fun, but it isn’t necessary.
In reality, it is usually not the rod, or the line that matters. It is the fisherman’s skill that determines how quickly a fish can be brought to hand, and understanding how to do so is one of the hallmarks of a proficient angler. If you’d like to learn a little more in this regard, here is an excellent article from Mid-Current explaining some of the basic principles and techniques: Fighting Big Fish
Now that article is directed toward saltwater fishing, but the principles are the same when you are fishing light lines and happen into a big fish. After all, a large saltwater fish on an eight or nine-weight may well be the equivalent of a large trout on a two-weight.
It needs to be understood that I’m not debating that the prolonged fighting of a fish is detrimental to its survival. That is a well researched fact. I’m simply stating that a light line and rod can be used to great effect, and without causing any more harm to the fish than if heavier tackle had been used. It just takes a knowledgeable angler to do so, and that leads to the real argument that holds water with me: How many fly fishermen truly have the expertise and mindset to use the lightest of fly lines and rods ethically?
To answer that requires some judgement, and personally, I would rather not go there. So the burden of honestly answering that question lies with the individual alone. Just remember, it’s more than acceptable, and perhaps even desirable to choose to use heavier line weights. If nothing else an angler can take comfort in knowing that they have more backbone in their rod than someone using a much lighter line weight will.
But for all those naysayers when it comes to light lines…. Let’s not spread ideology around that condemns another’s choice of equipment when there is nothing but opinion to support that position.
Light lines and rods aren’t toys. They’re effective fishing tools with certain limitations. But the ability to bring large fish to hand quickly and ethically isn’t one of them.
For the record, the lightest line weight rod the DFG currently owns is a 3 weight.