Fishing line has a number of qualities that are important to the angler. Two of the most misunderstood are line diameter related to pound test. The fish don't know what pound test is. You often will hear anglers say things like "We had to use 6lb test in order to catch fish, 8lb wasn't working as well". Yet one company's 6lb test can be thicker than another companies 10lb test! So knowing the brand and diameter of the line being used would be more important than just the pound test. Line diameter affects the line capacity of your reel, the sink rate of the line and the action of your lure. It also affects the ability of the line to withstand nicks and toothy critters' teeth. I like to use the thinnest line per pound test I can find in most instances. When anglers are casting lures or fishing live bait and complain that their line is too heavy, it's the diameter that is often retarding their casting ability, lure action or live-bait presentation. Thick line can really hamper the action of a lure as well as impede the swimming action of a live minnow. I don't think most fish are nearly as line shy as anglers give them credit.
Pound test is an arbitrary label. Many lines listed as testing "10lbs" actually break at 12 or 13lbs. Sometimes even higher. There's nothing to stop a company from marketing actual line testing at 14lbs test as the following:
Superstrong 8lb test
High grade 10lb test
Ultra thin 14lb test
It's ridiculous but true. In Europe anglers are more concerned with line diameter than pound test from what I've heard. Let's compare a few lines and their diameter vs. labelled breaking strength - and keep in mind that these diameters and pound test ratings are probably erroneous as well!:
Damyl Tectan 13.9lb test has a diameter of .0098"
Yozuri Hybrid's 12lb test has a diameter of .013"
Sufix Siege 6lbs test has a diameter of .010"
Edge Flourocarbon in 12lb. test has a diameter of .013 but a listed "breaking strength" of 17.6lb test. How idiotic is that? At least they are being honest with you (or so it seems.) Why is it called 12lb. test?
P Line Spectrex IV has a "15lb test" that has a "4lb diameter" (whatever that is) and it's listed diameter is .009". If you compare it to Tectan, it's a 13.9lb diameter.
12lb P Line Flourocarbon has a listed diameter of .011".
Maybe fishing lines should be used as good examples of "Marketing Gone Wild" in Marketing Classes. My advice is to look at the pound test rating, but also be very aware of the diameter of your line. Don't be fooled into being impressed by the strength of one companies 6lb test when in reality it's just 14lb test being sold as 6.