Saprolegnia as a Symbiont

Abstract

I have considered the Saprolegniaceae/Salmonid association from a layman's perspective for some time and now seek input from more competent authorities to support or dismiss the following concept. I wish to propose, as a testable hypothesis, that the Family Saprolegniaceae does not affect salmon as a pathogen but may function as a benign symbiont, critical in multiple aspects of the salmon life cycle. I submit it plays a beneficial role in the areas of nutrition, predation control, homing imprinting and even has the potential to limit smolt mortality at dams as well as in the impoundments. The association may provide multiple disease control mechanisms for juvenile salmon. It may also serve as a surrogate immune system for spawning adult salmon. Contrary to the common paradigm, the organism may prove beneficial even during residence in the marine environment. I suggest the effects of this relationship are so profound that salmon deprived of the affiliation will experience greatly diminished survival rates and may actually appear to be genetically inferior when compared with identical fish raised in the presence of Saprolegniaceae.