Re: Species specific fly lines
IMO, it's primarily a marketing ploy, however it's not a bad idea either as it allows newer folks in the sport to select lines based on the species they may be interested in chasing most. It would not surprise me if some lines, labelled for specific species, are not the same tapers, for different labels, since there are many species that will take similar flies of similar size/wind resistance & in similar conditions. How many different tapers can they design into a fly line anyway? Would slight differences in the tapers really make that much difference?
I've got a couple of species specific lines, purchased primarily because I got them at a very good price, and frankly for the fishing I do, cannot see much difference in them in how they cast. But, I rarely cast further than 50 ft, so may not be taking full advantage of each line. That's fine with me, as I rarely need to cast any further & still catch some fish. There are many variables that we encounter, so perhaps a species specific line is better for some folks, but not for others.
Again, IMO, the majority of us probably don't really need lines for specific species, as many of us fish for multiple species, and likely can't afford to have a single line for each species we target. It's highly likely, that most of us have general purpose lines rather than specialized, and they work fine for the fishing we do. I fished for many years with a level line, then eventually tried a DT, and settled on a single WF line, which I used for all the fishing I did. I'm primarily a bass, Striped Bass & panfish angler. Would a specialized line have improved my fishing? I really can't answer that!
If I really felt I needed a specialized line, then sure I would look into it, but as yet that has not been the case I don't believe.