With growing conceptual acceptability of fishery management techniques which advocate the reduction in the number of units of effort applied to overexploited and/or overcapitalized fisheries it is increasingly necessary that some readily usable measures be developed whihc may serve all those involved in fishery management and supporting research. Toward this end this paper examines the foundations of measures of fishing effort and fishing power as conceived within the domains of population dynamics and production economics. The degree to whiche ach discipline generates different and mutually exclusive measures is examined, along with an attempt to delineate a separate and distinct role for each discipline within the overall process of generating supporting information needed in all generalized fishery management plan.