Alaskans are preparing for another salmon season of poor to average runs to most regions.

The big exception once again is Bristol Bay, where another massive return of more than 51 million sockeyes is expected. Managers predict that surge will produce a harvest of more than 36 million reds for fishermen.

Bristol Bay is home to the largest wild sockeye salmon run in the world and typically accounts for 42% of the world’s sockeye harvest. Those fish and all wild salmon compete in a tough worldwide commodities market, where Alaska salmon claims 13% of the global supply. Farmed salmon product...