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MetricBycatch prevention and mitigation

Vessels using bycatch-reduction mechanisms

Measurement answer

What this metric measures

Reports the number and percentage of vessels using bycatch-reduction mechanisms, with separate disclosure for relevant gill-net or entangling-net vessels in cetacean bycatch-risk areas using acoustic deterrents or related technologies.

Specification

Metric specification

Result format
Structured table
Unit
number of vessels; percentage (%) — source-defined reporting unit
Reporting basis
Reporting period
Aggregation
Report vessel number and percentage separately by bycatch-reduction mechanism; separately retain the subset of bottom-set gill or entangling-net vessels operating in cetacean bycatch-risk areas that use acoustic deterrents or other sensitive-species entanglement-prevention or release technologies.
Pillar
Environmental
Topic
Bycatch prevention and mitigation
Controlled domain
Nature, biodiversity and land
Entity type
Metric

Reporting boundary

Vessels within the reporting organization's disclosed fishing-vessel boundary, including the separately identified gear-and-risk-area subset where applicable.

Verified source occurrences

Framework coverage

This is one canonical metric. The bindings below show every verified framework occurrence without creating duplicate metric pages. Edition, disclosure, role, and relationship remain source-specific.

  • Adopting Disclosure

    TNFD sector guidance

    Source evidence
    Publisher
    Taskforce on Nature-related Financial Disclosures
    Edition
    Final English sector guidance collection through August 2026 (17 documents)
    Requirement
    Not Specified
    Relationship
    Defines Disclosure
    Mapping outcome
    Direct Evidence
    Source locator
    TNFD Fishing sector guidance, additional sector metrics table, metric F.A23.4, p.89 | Page 89, additional sector metrics table, F.A23.4
    Open official framework source
  • Adopting Disclosure

    TNFD sector guidance

    F.A23.4
    Publisher
    Taskforce on Nature-related Financial Disclosures
    Edition
    Version 1.0, June 2025
    Requirement
    Recommended
    Relationship
    Maps Source Identity
    Mapping outcome
    Published
    Source locator
    Page 89, additional sector metrics table, F.A23.4
    Open official framework source
  • Adopting Disclosure

    TNFD sector guidance

    F.A23.4
    Publisher
    Taskforce on Nature-related Financial Disclosures
    Edition
    Version 1.0, June 2025
    Requirement
    Recommended
    Relationship
    Maps Source Identity
    Mapping outcome
    Published
    Source locator
    Page 89, additional sector metrics table, F.A23.4
    Open official framework source

Value structure

Dimensions and units

Unit
number of vessels; percentage (%) — source-defined reporting unit
Reporting basis
Reporting period

Unit meaning: Values use number of vessels; percentage (%) under the disclosed TNFD sector-guidance method, reporting period and boundary.

Table fields and units

  • Bycatch-reduction mechanism or technology
  • Vessel population description
  • Number of vessels using mechanism
  • Percentage of vessels using mechanism
  • Gear type
  • Cetacean bycatch-risk area status
  • Technology purpose

Published dimensions

  • Bycatch-reduction mechanism
  • Vessel count
  • Percentage of vessels
  • Gear type: bottom-set gill net or entangling net, where applicable
  • Cetacean bycatch-risk-area status
  • Technology type: acoustic deterrent, including pinger, or other technology
  • Technology purpose: prevent entanglement or aid release of sensitive species

Disclosure method

Formula information

Status
Not applicable
Formula type
Structured Disclosure

Disclosure form

No single formula

Report the source-defined result with its stated fields and method disclosures. F.A23.4 defines a reportable vessel-adoption metric family with two explicitly retained output forms: vessel count and vessel percentage. The general mechanism-use and cetacean-risk-area technology disclosures are compatible fields within one structured family, while preserving their distinct gear, location-risk and technology dimensions.

Verified sources

Evidence and status sources

Sustopedia checked each record-specific claim directly against primary publisher material. Labels distinguish current measurement authority from future compatibility and corroborative, legal, edition, or method status context. Corroborative evidence can support a stated limitation but cannot establish the core measurement by itself.

Measurement evidence

  • Measurement evidenceChecked 30 August 2026

    TNFD additional sector guidance collection

    Publisher
    Taskforce on Nature-related Financial Disclosures
    Edition
    Final English sector guidance collection through August 2026 (17 documents)
    Locator
    TNFD Fishing sector guidance, additional sector metrics table, metric F.A23.4, p.89 | Page 89, additional sector metrics table, F.A23.4

    Supports: The official TNFD sector guidance supports the identity, boundary and method basis of “Vessels using bycatch-reduction mechanisms”.

    Open official source

Use with context

Interpretation boundaries

Method disclosures required

Source-edition basis: TNFD sector guidance, Final English sector guidance collection through August 2026 (17 documents).

  • Disclose the vessel population and denominator used to calculate each reported percentage.
  • Disclose the bycatch-reduction mechanism or technology used by each reported vessel group.
  • Disclose the fishing-gear classification used to identify bottom-set gill or entangling nets.
  • Disclose the basis for identifying cetacean bycatch-risk areas.
  • Disclose whether the technology is an acoustic deterrent, such as a pinger, or another technology intended to prevent entanglement or aid release of sensitive species.
  • Disclose the organizational vessel boundary covered by the figures.

Record-specific limitations

  • A percentage is not interpretable without disclosure of the vessel population used as its denominator.
  • The acoustic-deterrent disclosure applies specifically to bottom-set gill or entangling nets in cetacean bycatch-risk areas and should not be generalized to all vessels.
  • Use of a mechanism indicates deployment and does not by itself demonstrate bycatch reduction effectiveness.

Interpret this metric with the stated reporting boundary, period convention, value shape, and unit. Results prepared with different boundaries or conventions may not be directly comparable.

Measurement evidence supports the core record-specific claims described above. Corroborative evidence can support limitations, while compatibility and status sources provide their separately labelled context. None of these cards by itself determines an organisation's legal applicability, filing readiness, assurance status, or compliance conclusion.