I agree that you can’t accurately determine the biomass in a stream with a fishing rod. That said, IMO, there are two different types of Class A’s…there are the very high “biomass bomb” type streams that are obvious Class A’s…there’s seemingly fish everywhere, even when they’re fishing relatively poorly and you’re not catching a ton of them. I’ve probably fished about a dozen (although there are surely many more) of these kinds of streams across the state…most are limestoners, but there are a couple small freestoners that fit in here too.
Then there are most of the other Class A’s on the list, which includes nearly all of the small freestoners…and Segloch…they’re probably pretty good, but they can still fish pretty poorly most of the time. On those types of streams, it’s hard to tell a low Class A, from a B or a C. How they fish is much more a function of conditions and the structure of the stream, than the actual biomass of fish in the stream. A steeper, plunge pool C will fish way better than a low gradient, low A in poor conditions…low, clear water for instance – which on small freestoners is often the norm. On a low Class A, a good day may turn up 20 or 30 fish or more, but a bad day may be a skunk and you’ll swear there’s no fish in the stream.
In any case, the one thing I’ve noticed with Segloch, which seems to be a common trend, is that there are seemingly more and more Browns and less Brookies. The Browns seem to be showing up further upstream as well. If it were resurveyed today (and was found to still be a Class A), I’d expect to see it relisted as a Brown/Brook mix.