The wild salmon run in Alaska is the biggest of its kind.
Each year over 40 million fish leave the Pacific Ocean and fight their way up to the headwaters of mighty river systems where they mate, spawn and die.
The young salmon make their way out to sea again and, year after year, as the fish swim back to their birthplace, fishermen are there waiting for them.
For this two-part documentary, the BBC's Nick Rankin reports from Alaska during the wild salmon run and joins commercial and subsistence fishermen who live off this natural resource.
Nick Rankin travels to the Bristol Bay area in Alaska to see how humans are exploiting the greatest wild salmon run on earth.
He joins a commercial fishing boat at the mouth of the Egigik River to find a strictly regulated fishery and hardened crews who fight it out to get the best spots and the biggest catches.
Nick also throws the net out on the Wood River with a native Yupik man whose people have subsistence fished the Alaskan salmon for millennia.
Produced by Neil McCarthy and first broadcast on 29 October, 2010