It's certainly possible that the number is simply wrong, but it seems to be sourced from this publication: https://asafishing.org/uploads/2011_ASASportfishing_i

It's certainly possible that the number is simply wrong, but it seems to be sourced from this publication: https://asafishing.org/uploads/2011_ASASportfishing_in_America_Report_January_2013.pdf https://asafishing.org/uploads/2011_ASASportfishing_in_Ameri... (adding State and Federal totals at the bottom of Page 8). $15 Billion of taxes on $50 Billion of total expenditures does seem high, but not totally implausible. The right doubt might be whether there are really $50 Billion of annual expenditures on Recreational Fishing in the US. I suspect they are double counting a lot of things: if one goes fishing once on a vacation, they might be counting the entire travel cost of the vacation as a fishing expenditure. Edit: I said "seemed to be" because I was proud to have found that page on my own. But as another poster pointed out, that page is directly linked from the article so there is no doubt it is the source.