I just attended a really interesting seminar put on by the U.S. and Canada salmon negotiators. They told us they use a ton of info, including constantly updated computer models, redd counts, smolt counts, commercial catches at sea over a three year period, (chinook are taken at sea as three, four and five years old fish), sport catch rates and a ton of other data. They did not mention jacks, but that may be a small part of the info they consider.