Edit (or Correction, not Perfection): TAB reader Cromely has pointed out that the freighter wasn't the one in the Salmon paint scheme but instead a converted freighter in regular livery. You can read the rest of his post here. The corrected post:
Alaska Airlines' famed 'Salmon-Thirty-Salmon', with a 120-foot long salmon painted on its fuselage, was met at Seattle-Tacoma Airport this morning by a Boeing 737-400 freighter carrying over 32,000 pounds of Copper River salmon onboard. Throughout the day, according to the company, Alaska will deliver over 160,000 pounds of Copper River salmon throughout the country on eight flights from Cordova, AK to Seattle, where the fish will then be flown out throughout the country.
Up until recently Alaska has relied on Boeing 737-200s to haul freight, but they were getting expensive (both in terms of fuel costs and maintenance), so with those gone, and newer Boeing 737s on order, Alaska was able to convert the -400s into freighters.