Pathways of Effects - National Guidelines
Illustrating the links between human activity and its potential impact on aquatic ecosystems

Table of Contents

Acronym list

Area of Interest
Best Management Practice
Canadian Environmental Assessment Agency
Canadian Science Advisory Secretariat
Coastal Management Area
Fisheries and Oceans Canada
Driving forces-Pressures-State-Impacts-Responses
Ecological Risk Analysis
Ecosystem Overview and Assessment Report
Ecosystem-based Management
Environmental Assessment
Environmental Protection Agency (United States)
European Environmental Agency
Integrated Oceans Management
Large Ocean Management Area
Marine Protected Area (generic)
Organisation for Economic Co-operation and Development
Pathway of Effect
Pathway of Effect National Working Group
Regional Environmental Assessment
Social, Economic and Cultural Overview and Assessment
United Nations Environment Program
Valued Ecosystem Component

List of figures

  • Figure 1: PoE main elements and example
  • Figure 2: Examples of PoE design, terminology and labels used in conceptual modeling
  • Figure 3: Example of a holistic PoE model
  • Figure 4: Example of a holistic model with common pressures generated by aquaculture and marine transportation sectors, and associated detailed PoE for aquaculture
  • Figure 5: Example of a species-based model
  • Figure 6: Example of a pressure-based model (generic)
  • Figure 7: Example of a socio-cultural and economic model
  • Figure 8: Example of an activity or action-based model
  • Figure 9: Example of a sector-based model

List of tables

  • Table 1: Draft Integrated Management / Ecosystem-based Management planning process
  • Table 2: Example of pressures and environmental indicators


The following Pathways of Effect National Guidelines are intended to help ocean management practitioners to apply Pathways of Effect (PoEs) for the implementation of Integrated Management (IM) and Ecosystem-based Management (EBM) within Canada’s coastal regions and oceans. Developed by a Fisheries and Oceans Canada (DFO) Pathways of Effect National Working Group (PoE-NWG) for planners and decision-makers within DFO, these guidelines may also be useful for the identification, assessment and management of the potential impacts of human activities on aquatic ecosystems and their resources.

Using these guidelines

Section 1 and section 2 provide the regulatory context in which PoE models are developed and position the models within the larger practice of ecosystem-based management.

Section 3 describes the benefits of using such models and details the core elements of PoE design.

Section 4 outlines the ecological unit considerations for the use of PoEs in the IM context and defines the three current categories of models in use at DFO.

Section 5 provides step-by-step instructions on how to develop a PoE model – from the identification of participants and selection of endpoints, to the identification of ecological impacts and scientific validation.


Ocean planners and environmental managers work to maintain marine ecosystem health, ensuring that significant or valued ecosystem components (VECs) and services are not compromised by human activities. But how do they describe and measure the complex and multi-faceted relationships between human activities and their potential impacts upon aquatic ecosystems? One widely used approach is a modeling tool known as a Pathways of Effect – or PoE.

Knowledge and expertise about PoE development at DFO evolved from traditional fish management advice to broader application within EBM, using various PoE model types. This ‘ever green’ document describes the role of PoEs within broader planning processes, the types of PoE models currently in use, their potential applications, and a step-by-step process for their development.

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