Hatchery Salmon and Ecological Overshoot

Abstract

Is there an ecological niche for ‘ocean ranched’ hatchery salmon, Oncorhynchus spp., to supplement wild salmon? Ecologically, I hypothesize that the carrying capacity for biota is: (1) limited; (2) filled with locally adapted biota competing and cooperating to nurture viable offspring; and (3) sustained by the biogeochemical recycling of their nutrient elements. Thus, biotic abundance is limited more by the space and food needed to nurture viable adults than by the numbers reproduced. Hatchery immigrants compete for space and food with wild biota, spawn with and reduce the fitness and biodiversity of wild salmon, and their growth and commercial harvest consume more biogeochemical resources than they recycle. This contributes directly to ecological overshoot and to the declining or depressed populations of wild salmon, Pacific herring Clupea pallasi and eulachon Thaleichthys pacificus now observed in Southeast Alaska and wherever there are production releases of hatchery salmon. Industrial-scale hatcheries do not have a niche in sustainable salmon management.