Craig Medred has been investigating the negative impact of hatchery pinks on the North Pacific.  A yearly release of a couple billion pinks is starting to impact the carrying capacity of the ocean itself - carrying capacity being the amount of food for the fish.  Pinks compete really, really well and are voracious predators.  Release too many pinks and eventually there is not enough for the birds and other salmon species, which may help explain the crashes in other species (king, coho, chum) returns.  

Solution?  Farming (ranching) Pacific species and ratcheting back on the release of hatchery fish.  Cheers -