Salmon was the first Alaskan fishery to be certified sustainable by the UN FAO’s Responsible Fisheries Management (RFM) program since it was adapted by the state in 2010.
Alaskan fisheries were Marine Stewardship Council (MSC) certified until 2012, when the state decided to switch to the RFM program because it is the “most well known internationally-agreed set of principles for responsible fisheries management”. Read more here.
Here is an example of salmon sustainability measures, taken from the Alaska Seafood website:
“…before fishing is opened, state biologists make sure ample numbers [of salmon] have already passed upstream to lay eggs. A variety of methods are used to ensure ample escapement. One of those methods is stationing state fishery workers in towers above the water to count individual salmon as they swim up current. When biologists ascertain that the quota for a particular run has escaped, word goes out by radio to boats waiting beyond the river mouth. And so, in-season harvest decisions are made on local rivers by personnel who know the fishery best.”
(Source: http://sustainability.alaskaseafood.org/)