Clerk,

It's true the way it's used in the example illustration. However, context matters. Salmon and steelhead populations are subject to both density dependent and density independent mortalities. The ODFW example is consistent with density independence.

A different outcome would be a coho or steelhead group that suffered a low egg to fry survival, but due to the low fry density, that population segment might have a higher than average fry to parr or smolt survival rate. Funny thing about fish populations; it isn't always simple math. If it was, we'd have right answers more often.

Sincerely,

Salmo g.