salmonoid wrote:
It is, but I'd argue it is somewhat meaningless and somewhat suspect. I don't know what methodology the state used to determine their numbers, both for their average number of legal brookies and 9"+ brookies per mile, and for their harvest rate of 7 fish per mile, and finally, what the total miles of stream that support those numbers. As with any study or formula, a small sample size is extrapolated to create an "average" across a whole state. Small errors upon small errors in formulas or study biases, multiplied by 34 years can yield a big error in the final number. Just look at the wide variance in legal fish in the 2006 Biologist Report (Jeans, Kistler, and Wolf Swamp Run). Sampling in three or four years swung as much as 90 legal fish per mile (Kistler) and Jeans yoyoed from 47 to 5 to 43 to 11. Ten samples of fish from approximately 300m stream lengths in three or four different years yields a lot of noise that is mirrored across all the other streams sampled in the state.
This
paper, about the economic impact of wild trout angling lists an abundance of legal size wild brook trout at 75.5/mile for the 76 streams studied. And if you read it closely, you can see how sampling error (and even angler answer bias) might skew the results.
Going back to the 34 legal fish/mile, I find it hard to believe that 20.5% of the legal wild brookies in PA are harvested. I'll bet that less than 20.5% of the legal wild brookies in PA are even caught, let alone harvested.. I can't remember the last time I've even saw a wild brookie creeled or on a stringer.
Anyway, my whole point is to not get too up in arms about a number derived by multiplying a couple of calculated numbers together. It's a number based on a model that probably has a number of flaws, over-representing some things, under-representing others and probably completely missing some important elements.