Determining the Status of Fish Stocks in Data-Poor Environments and Multispecies Fisheries

The document provides an overview of data-limited assessment methods and adaptive management frameworks, such as FISHE, to help governments identify overfished stocks and implement subsidy prohibitions even when comprehensive quantitative data is unavailable.

• Over 80% of global catches occur in fisheries that lack the data, resources, and infrastructure required for quantitative model-based stock assessments to estimate biomass and fishing mortality relative to reference points.
• Conventional stock assessment methods are often unsuitable for tropical fisheries because they are typically data-intensive, based on single-species models, and fail to account for ecosystem interactions, spatial heterogeneities, or the presence of multiple interacting species and gear.
• In data-poor environments, stock status can be established using empirical indicators (such as catch per unit effort, mean length of fish, or catch levels) and model-derived indicators, or through proxies when fishing mortality or biomass cannot be explicitly estimated.
• The Framework for Integrated Stock and Habitat Evaluation (FISHE) is an 11-step adaptive management tool that allows for science-based regulations in resource-limited conditions by using stakeholder inputs, vulnerability assessments, and multiple independent data streams to reduce uncertainty.
• Multispecies fisheries are prone to 'serial depletion,' where individual stocks are depleted sequentially. FISHE manages this by organizing species into 'baskets' or 'tiers' and using representative species for assessments to determine if target species are overfished.
• For WTO subsidy negotiations, a flexible definition of 'overfished' that allows for 'alternative reference points' would enable member governments to use various indicators, proxies, or local fishers' knowledge to trigger subsidy prohibitions.

APA

Headley, M. (2020). Determining the Status of Fish Stocks in Data-Poor Environments and Multispecies Fisheries. International Institute for Sustainable Development. https://www.iisd.org/system/files/publications/fish-stocks-multispecies-fisheries.pdf

Chicago

Headley, Maren. Determining the Status of Fish Stocks in Data-Poor Environments and Multispecies Fisheries. International Institute for Sustainable Development, 2020. https://www.iisd.org/system/files/publications/fish-stocks-multispecies-fisheries.pdf.

Wikipedia

{{cite report |last1=Headley |first1=Maren |title=Determining the Status of Fish Stocks in Data-Poor Environments and Multispecies Fisheries |publisher=International Institute for Sustainable Development |date=June 2020 |url=https://www.iisd.org/system/files/publications/fish-stocks-multispecies-fisheries.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{headley2020determining, author = {Headley, Maren}, title = {{Determining the Status of Fish Stocks in Data-Poor Environments and Multispecies Fisheries}}, institution = {International Institute for Sustainable Development}, year = {2020}, month = jun, url = {https://www.iisd.org/system/files/publications/fish-stocks-multispecies-fisheries.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }