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.
Vast deposits of gold and copper have been discovered in the headwaters of Bristol Bay near the salmon spawning grounds.
Nick Rankin explores the implications of the proposed mining of these minerals for Alaska's main industry: salmon.
The issue is highly controversial, even more so after the recent Gulf oil disaster.
Conservationists, commercial fishermen and many native people fear that the massive open-pit mine will disrupt the salmon rivers and inevitably lead to contamination and the fish will not return to spawn.
The mining company and some of those living close to the proposed mine see development opportunities and wealth generation and vow to protect the environment.
What is the future for the Alaskan salmon, the king of fish?
Produced by Neil McCarthy and first broadcast on 5 November, 2010