Oregon Public Broadcasting

A new study in the journal Nature says population diversity is a crucial, if underappreciated attribute to a healthy salmon fishery. 

Two University of Washington researchers co-authored the paper.  It says river systems without a wide array of distinctive populations are more prone to failure. 

Professor Ray Hilborn uses the struggling Sacramento River to explain what he means.

Ray Hilborn: "Mining and dams eliminated many populations and hatchery production homogenized those fish that remain.  So now all the fish are going to the ocean at the same time and place.  Depending on the conditions, they either boom or bust."

Hilborn and his co-author quantified how big a difference variety makes by examining fifty years of records from Bristol Bay, Alaska. 

The researchers attribute the steady performance of the Bristol Bay fishery to having the salmon equivalent of a well-diversified investment portfolio. 

Hilborn compliments policy makers in the Northwest for their recent emphasis on hatchery reform and prioritizing wild salmon runs.