Fisheries dictionary

INSTANTANEOUS RATE OF NATURAL MORTALITY

When natural and fishing mortality operate concurrently it is equal to the instantaneous total mortality rate, multiplied by the ratio of natural deaths to all deaths. Also called: force of natural mortality.

  1. instantaneous rate of natural mortality—when natural and fishing mortality operate concurrently it is equal to the instantaneous total mortality rate multiplied by the ratio of natural deaths to all deaths Rick...Dictionary of ichthyology