Catastrophic senescence of the Pacific salmon without mutation-accumulation

We derive catastrophic senescence of the Pacific salmon from an aging model which was recently proposed by Stauffer. The model is based on the postula tes of a minimum reproduction age and a maximal genetic lifespan. It allows for self-organization of a typical age of first reproduction and a typical age of death. Our Monte Carlo simulations of the population dynamics show that the model leads to catastrophic senescence for semelparous reproductio n as it occurs in the case of salmon, to a more gradually increase of senes cence for iteroparous reproduction.