the problem currently in the north pacific is too many fish with usa, Canada, japan, Russia releasing from commercial hatcheries 8 billion smolt a year to add to the estimated 2 billion wild fish, there is not enough food. also Canada has introduced atlantic cage rearing around Vancouver island and this has introduced a devastating disease into the pacific that has wiped out millions of wild salmon. another problem up there is that the commercial hatcheries have been releasing their smolt at the same time as wild smolt descend the rivers and as hatcheries smolt are bigger they out compete the wild ones. in nz a 5 year salmon is very rare the main age is 3 years and to have a healthy fishery you need to have all year classes present in a run. trawlers now catch very few salmon as it is no longer worth their while as they can’t compete price wise with farm reared ones and monitoring is so much better now with remote technology. f&g estimates are always an under estimate as they can’t count all fish that spawn or are caught. from their surveys. they need to ensure that the number of fish that spawn is not too many and not too little. the fact remains that from 1960 85% of all salmon caught up until the mid 1990’s were glenariffe releases and when that closed that took 85% of the fish out of the system and we are now getting that back through hatchery releases. I do agree with you about stopping fishing in the upper reaches of the rivers that was proved on the rangitata a few years ago.