The complexity of equations that judge the resilience of salmon is dizzying: depensatory effects of small population size; compensatory survival at low rearing density; genetic effects of hatchery fish; straying; habitat; random events; cyclic variation; fecundity; sex ratio; persistence time on spawning grounds; habitat volume and spawning distribution; homing fidelity; extinction vortex parameters; life-stage survival rates.
Scientists labor over parameters, assumptions, transformation, and error terms; run models to represent a thousand generations, or a century, testing scenarios of deteriorating, similar, or improving ocean conditions.
As I write, wild winter steelhead are spawning in coastal rivers. Eggs are incubating in the gravel as they have for over ten thousand years. Coho and Chinook fry are emerging from nooks and crannies, seeking shelter at river’s edge. Sculpin and cutthroat steal precious little food from salmon these days; the coon and otter fight over too few carcasses. An ecological rain of nutrients carried to these rivers from ocean, abundant for millennia, has withered to a barely recognizable trickle.
People are deeply divided over what the science of salmon resilience seems to be saying. Some see a politically motivated sham, a contrivance to deny that salmon are in trouble. Some think that the science of salmon resiliency is merely stupid, because these fish, quite obviously, are headed toward extinction. Some, though, accept the science of salmon resiliency. Extinction is not an issue, they say. Most of the people I know have quickly decided to accept it or reject the science of salmon resilience.
Personally, I don’t accept or reject, believe or disbelieve.
The science of salmon resilience is young, yet it claims to understand the soul of nature. I listen, and consider the advice this young science gives. I choose to resist outright acceptance or rejection of this young science. I am optimistic when I read that salmon are likely to rebuild if we don’t mistreat them too much. I choose to be skeptical when people claim science proves that salmon are bullet-proof.
Time will tell.