Initial Publication Date: August 12, 2008

Oh What a Tangled Web: Ecosystem-Based Management

Part B: Integrated Ecosystem Assessments

EBFM is a particularly promising approach for the improvement of commercial fisheries management. A more thorough understanding of the complexities of the ecosystem in which exploited or depleted fish species live can help researchers better predict the effects of the ecosystem on fishing and the effects of fishing on the ecosystem. When managing a commercial fishery, ecosystem complexities are compounded by economic complexities and the need to sustain a profitable business as well as a healthy ecosystem.

Integrated Ecosystem Assessment programs (IEAs) are used to support effective EBFMs within NOAA Fisheries. Using an integrated science approach, IEAs aim to balance the needs of nature and society today and into the future while also supporting diverse marine resource management objectives in an ecosystem context. IEAs provide a way to assess ecosystem status relative to objectives of different groups (e.g., fishing, recreation, energy production, shipping, agriculture, forestry, food, clean water), account for the holistic impact of management decisions, and guide management evaluations. IEAs consist of analyses that help resource managers make more informed and effective management decisions. For example, IEAs contain:

Assessments of status and trends of the ecosystem condition, including ecosystem services.
Assessments of activities or elements in an ecosystem that can stress it.
Prediction of the future condition of the ecosystem under stress if no management action is taken.
Prediction of the future condition of the stressed ecosystem under different management scenarios, and evaluation of the success of management actions in achieving the desired target conditions.

1. Watch this short introductory video about IEAs.

What is an IEA? If video does not play, visit Monterey Bay's EBM page.

2. Learn about each step of the IEA:

Step 1: Define the System and the Goals

Defining goals provides focus and a measure for progress. In order to achieve those goals, it is key to understand the place and context, or ecosystem (including inter-related system components). A tool for understanding the ecosystem is a Conceptual Model.

Show me an Example of a Conceptual Model for Halibut - Sitka, AK

This conceptual model for halibut was modified with direct input from Sitka Community members who have in-depth knowledge of the community's interaction with their local fisheries. These community members were asked to draw everything they thought affected the halibut as well as everything they thought halibut affected or impacted. Key biological and environmental components and linkages among these components were identified. Scientists reviewed all the model drawings to determine topic groups and factors that were not already identified in previously assembled models of halibut based on scientific literature. Therefore, those factors were a direct contribution from the Sitka community to the scientific-based models.

Steps 2 & 3: Select Indicators & Assess Ecosystem

Indicators capture the status and trends of key ecosystem components defined in Step 1. They should represent status and trends of individual components but collectively reflect the condition and trajectory of the socio-ecological system when considering the whole ecosystem.

Show me an Example of Indicator

These copepods are biological indicators for changes off the coast of California. Copepods, which reside at the bottom of food chains, are considered a key food source for small fish and crustaceans that feed larger fish, marine mammals, and seabirds. They drift on ocean currents, which means they are good indicators of both the type and sources of waters in the California Current. Copepods from northern waters are made up fewer species, but they are higher in fat content that helps fish grow and survive through winter. Southern copepod species are lower in fat and have less nutritional quality, as well as being smaller. Copepod richness has been a useful predictor of salon abundance and linked to seabird nesting success in Central California.

Step 4: Assess Risk

By conducting a risk assessment, it is possible to determine the probability of undesirable events occurring to ecosystem components identified in Step 1. Risk is generally described by the sensitivity and/or resilience of a given ecosystem component (measured by indicators) to various natural and human pressures and changes that result in change to the ecosystem.

Show me an Example of a Risk Assessment

The Alaska Climate Integrated Modeling (ACLIM) project is developing multi-model assessment of climate change impacts on fish, food-webs, and fisheries in Alaska. The integrated modeling looks at the far-reaching impacts of environmental changes in the Bering Sea under high and low emission scenarios and various alternative harvest strategies.

Step 5: Evaluate Management Strategies

Building off information from the previous steps, evaluation management strategies considers potential outcomes of alternative management actions on ecosystem components (natural and human) and identifies trade-offs within management objectives. These evaluations inform managers which strategies could be the most useful in achieving their objectives.

The ocean off the west coast of Hawai'i Island is very important for biodiversity and human society. This part of the ocean includes the largest Hawaiian expanse of intact coral reef. The ecosystem is vulnerable to many pressures: increasing population, coastal development, fishing, pollution, and climate change. Five different management strategies were evaluated by measuring their impact on three ecosystem services. Pressures including fishing, land-based pollution, climate change, and coral bleaching were incorporated.

3. Visit An Evaluation of Management Strategies West Hawai'i Project to read about Hawai'i Island's evaluation of management strategies.

Checking In

Answer the following questions to check your understanding of information presented in the Evaluation of Management Strategies West Hawai'i Project

What were some of the indicators in the West Hawai'i Island marine ecosystem?
Show me the answer
What was likely to happen if no changes were made based on the evaluation?
Show me the answer

After an Evaluation of Management Strategies

After a Management Strategy Evaluation, one of the suggested actions is selected and implemented. Indicators continue to be monitored as it's important to learn if the action has been successful or not. If the action has been successful, the status, trends, and risk to the indicators continue to be analyzed regularly for change. If the action has not been successful, the outcomes are assessed and evaluated to refine goals and targets or indicators in order to achieve the original objectives.