Pathways of Effects

Pathways of Effects (PoE) diagrams are used to describe development proposals in terms of the: activities that are involved, the type of cause-effect relationships that are known to exist; and the mechanisms by which stressors ultimately lead to effects in the aquatic environment.

Each cause-and-effect relationship is represented as a line, known as a pathway, connecting the activity to a potential stressor, and a stressor to some ultimate effect on fish and fish habitat. Each pathway represents an area where mitigation measures can be applied to reduce or eliminate a potential effect. When mitigation measures cannot be applied, or cannot fully address a stressor, the remaining effect is referred to as a residual effect.

To support you in the development of a project proposal, a series of PoE diagrams were developed for common land-based and in-water activities associated with a broad range of development proposals.

The PoE diagrams were developed in consultation with habitat biologists, engineers and scientists from across the country, in order to ensure that most of the known effects on fish and fish habitat were included. The PoE diagrams will be updated as additional activities and stressors are identified.

PoE diagrams can be used by both Fisheries Protection practitioners and proponents to:

  • Review the potential effects of individual development proposals;
  • Identify appropriate mitigation measures;
  • Develop guidelines and best management practices; and
  • Assess the effects of alternative design options.

Although the PoE diagrams may appear complex at first glance, they are actually quite simple to use, and by selecting the appropriate activities for a given development proposal, they offer a clear picture of the overall potential effects of the proposed development on fish and fish habitat. It is important to note that the pathways are highly generalized and require proponents to apply expert judgment in determining which pathways apply in the geographic location of the proposed development activity.