Indicator 2.2.11

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System

Water Type

Feed Dependent

Species

Indicator 2.2.11

by Contact on 8 October 2026

Requirement

Indicator applicability: bivalve culture The UoC shall1919An exemption to Indicator 2.2.11 applies for situations where the total surface area of aquaculture within a waterbody is less than 10% of the total surface area of the waterbody. ensure that total bivalve culture in a waterbody does not result in phytoplankton depletion either by: a. demonstrating that the waterbody has a ratio of Clearance Time (CT) over Retention Time (RT) > 1, following the method outlined in Appendix 5. Where CT over RT is <1, demonstrate that the waterbody has a ratio of CT over Primary Production Time (PPT) > 3, following the method outlined in Appendix 5; or b. conducting a modelling study that demonstrates that the carrying capacity of the waterbody is not exceeded.

How Do I Interpret This Requirement?

  • The ratio of Clearance Time (CT) and Retention Time (RT) demonstrate whether the carrying capacity of a waterbody for bivalve production has been exceeded.

  • Primary Production Time (PPT) is calculated when cultured bivalves may negatively impact the carrying capacity of a waterbody.

Evidence of Implementation

  • The method used to calculate CT, RT and PPT, in accordance with Appendix 5.

    • Maps demonstrating whether the site is in an easily definable waterbody. This will support the selection of the correct method in Appendix 5 (5.2) regarding estimating the zone of influence.

  • Results demonstrating the ratio of CT over RT, or CT over PPT.

  • A modelling study has been conducted to demonstrate the carrying capacity of the waterbody, if the method outlined in Appendix 5 has not been followed.

Auditors Should Confirm

  • Methods and results have been presented demonstrating the ratio of CT over RT, or CT and PPT depending on whether CT over RT > 1, in accordance with Indicator 2.11.

  • A modelling study has been conducted to demonstrate the carrying capacity of the waterbody, if the method outlined in Appendix 5 has not been followed.

    • The modelling study shall demonstrate carrying capacity has not been exceeded.