Consistent and transparent measurement of GHG emissions following a life cycle assessment approach is necessary to underpin effective GHG reduction and management and to inform broader efforts to understand and reduce the GHG impact of global food systems.

This indicator ensures that all ASC certified sites undertake this important first step in contributing to efforts to combat climate change.

ASC does not require the use of any particular GHG calculation framework or tool or conformance with any particular GHG methodology or standard. However, some methodological requirements are stipulated in Appendix 9 to ensure a sufficient level of consistency, completeness and accuracy of GHG calculations.

Certificate Holders should consider the reporting format of the ASC Farm Standard GHG Data Submission Template in undertaking their calculations.

This includes the characterisation of GHG emissions in three distinct ways:

GHG profiles for feeds used, specific to the feed supplier and species or species group and updated on an annual basis, as required to be shared by the feed supplier according to Criterion 1.21 of the ASC Feed Standard and using the format of the ASC Feed Standard GHG Data Submission Template.

For marine salmonids only: GHG profiles for any supplying grow-out site(s) as required to be shared by the previous grow-out site(s).

Documentation of the source of any GHG emission factors used.

This may be documentation of calculation tools (e.g., the ASC GHG Calculator) or documentation of specific emission factors and their source if calculating emissions manually.

Documentation of the input variables used (e.g., quantity of electricity).

Inputs of energy should reflect those calculated in Indicator 2.10.1. All input variables should be supported by evidence such as invoices or feed use records if requested.

Documentation of conversion factor and, if applicable, allocation factors, used to convert GHG calculations from a live weight basis to an edible weight basis.

Documentation of power purchase agreements, if applicable, to demonstrate use of electricity from specific dedicated sources rather than the national or regional electricity grid.

Records of GHG profiles from feed suppliers and (for marine salmonids) prior grow-out sites are available.

GHG emissions are calculated in kg CO~2~e relative to live weight production and edible weight product and recorded using the ASC Farm Standard GHG Data Submission Template.

If using a tool other than the ASC GHG Calculator, documentation showing how the tool conforms to the methodological requirements outlined in Appendix 9;

This may be a signed declaration from the tool provider or highlighted elements in the tool’s user documentation.

Values input into the ASC GHG Calculator, another tool, or manual calculations are supported with evidence (e.g., fuel purchase invoices).

If undertaking calculations manually, demonstration of the calculations undertaken, including the use of GHG data from feed suppliers and (for marine salmonids) prior grow-out sites in conformance with the requirements of Appendix 9.

The scope of included activities reflects the requirements outlined in Appendix 9.

GHG emissions are not adjusted using carbon credits or offsets.

Certificate Holders are encouraged to use the ASC GHG Calculator, available at https://ghg.asc-aqua.org, to ensure compliance with regards to calculation scope, methods, data sources and reporting format. Use of this tool is voluntary; other tools, consultants, or internal procedures may be used if documentation is available to demonstrate compliance with the requirements in Appendix 9.

Recommended factors for converting GHG emissions from a live weight basis to an edible weight basis may be sourced from supplemental material of Gephart et al. (2021). Other conversion factors may be used if they reflect the actual edible yield (i.e., muscle fraction) of the animal.

A range of methodological frameworks and standards are available to guide life cycle assessments and GHG accounting. Use of any of these is optional, provided that calculations are still in compliance with the requirements of Appendix 9. Examples include:

Tracking use of energy inputs is a necessary step in calculating the GHG emissions associated with aquaculture production and products.

Energy inputs include all those sources of energy used for the purpose of production, including electricity and energy carriers such as diesel or natural gas.

To the extent possible, Certificate Holders are encouraged to calculate energy use specific to the certified site. However, in some cases, this may be difficult to do. For example, fuel purchased may be used to supply vessels servicing many sites, potentially both certified and non-certified sites or even multiple sites or companies.

In these cases, a portion of the overall input may be allocated to the certified site based on a logical allocation basis.

For example, dividing energy inputs between sites based on the relative number of vessel trips or using the site’s relative share of production among the group of sites serviced.

Energy inputs to hatcheries are not included in calculations of on-site energy use. However, in cases where the juvenile stage of the supply chain is integrated with grow-out, sites may choose to include this stage in their calculations to simplify calculations.

Documentation of energy intensity factors (e.g., MJ of energy per L of diesel) used if they are different to the default values used in the ASC Farm Standard Energy Use Data Submission Template.

Evidence to support the quantity of each energy input specified in calculations is available on request, along with any allocation of energy inputs between multiple sites if applicable.

This may be, for example, fuel purchase invoices or electricity use records.

The energy use value is calculated and reported in MJ of energy per tonne of live weight production.

Energy use of production is calculated for either (a) the most recent completed production cycle; or (b) three consecutive years of production.

Documentation is provided to support input variables and calculations.

The ASC Farm Standard Energy Use Data Submission Template is used to demonstrate results.

Certificate Holders are encouraged to use the ASC Farm Standard Energy Use Data Submission Template for calculating the energy intensity of production after energy inputs are quantified.

Additional energy intensity factors for a range of energy inputs are available from the UK Department of Energy Security and Net Zero.

Water levels in groundwater wells should be tested and recorded at similar times during the year.

Monitoring of water levels in groundwater wells determines whether water is being replenished in the ground. When water abstraction increases beyond the rate of replenishment, the result is a reduction in the water table.

Results from the monitoring of water levels in groundwater wells.

Documents demonstrating the monitoring results have been included in, and informed revisions of, the WEMP (where required).

Regulatory records which provide evidence of the recording of water levels, if monitoring is not permitted by law.

Monitoring results have been presented which demonstrate the recording of water levels in groundwater wells.

Monitoring results have informed the drafting or revision of the WEMP.

The responsible disposal of biosolids mitigates impacts on natural ecosystems and waterbodies.

The UoC should develop and implement a biosolids management plan which procedures relating to the responsible disposal of biosolids.

Documents outlining the process and location of biosolids disposal.

The documents should demonstrate biosolids are disposed of responsibly. An example may be a biosolids management plan.

The management plan may include a flow diagram that outlines key steps for the disposal of biosolids.

If biosolids are transferred to a third party, evidence should be available to confirm that the third party has disposed of biosolids responsibly.

Documents, for example a biosolids management plan, have been presented which demonstrate the responsible disposal of biosolids.

If biosolids are transferred to a third-party, evidence has been presented to confirm that the third-party has responsibly disposed of biosolids.

The following outlines examples of the purposes for uncontaminated biosolids re-use:

Documents demonstrating the appropriate treatment and re-use of biosolids.

An example may be a biosolids management plan.

The management plan may include a flow diagram that outlines key steps for the treatment of biosolids prior to re-use to ensure they are uncontaminated.

Documents, for example a biosolids management plan, have been presented which demonstrate only uncontaminated biosolids are re-used.

This requirement will mitigate impacts on water quality and the risk of salinisation, therefore supporting the implementation of Criterion 2.6 and 2.7 respectively.

Records which demonstrate:

Records have been presented which demonstrate biosolids are not disposed of and/or released into receiving waterbodies, natural wetlands or other ecosystems.

There is no evidence of the discharge and/or release of biosolids into receiving waterbodies, natural wetlands or other ecosystems during the audit.

The UoC should develop and implement a biosolids management plan, which includes procedures relating to the containment of biosolids.

The appropriate containment of biosolids should consider the risk of runoff during anticipated and/or recurring extreme weather events, such as tropical storms or flooding.

Documents demonstrating the appropriate containment of biosolids. An example may be a biosolids management plan.

The management plan may include a flow diagram that outlines key steps for the containment of biosolids.

Documents, for example a biosolids management plan, have been presented which demonstrate the appropriate containment of biosolids.

Conformance should be confirmed through a visual inspection of the site.

Freshwater wells with a conductivity or chloride concentration above the thresholds in Indicator 2.7.4 will demonstrate that salinisation has taken place.

Specific conductance or chloride concentration should be monitored at a frequency adapted to fluctuations due to natural factors, such as seasonal rains.

Records of specific conductance of freshwater wells on, or in proximity to the site (within 1km radius).

Regulatory records obtained where applicable, to demonstrate well-monitoring is not permitted by law.

Monitoring records are available for freshwater wells in proximity to the site, which demonstrate either conductivity or chloride concentration is below the relevant threshold specified in Indicator 2.7.4.

Monitoring has taken place at least every six months and considered natural factors, such as seasonal rains.

Regulatory records are available for instances where well-monitoring is not permitted by law.

The records demonstrate conductivity testing has taken place.

Hand-held refractometers can be used to measure salinity. These devices are appropriate for salinities of approximately 2 or 3 ppt, but they are not sensitive enough to determine if sites are causing the salinisation of freshwater bodies.

The quickest and easiest method to evaluate salinity of water is to measure specific conductance with a conductivity meter. An alternative method is a chloride test kit, which is typically cheaper.

For UoCs located in tidal systems, timing of measurements should correspond with high and low tides, to reflect variations related to the tidal regime.

The UoC can conduct DO monitoring immediately downstream of the last site in a waterbody whilst still following the sampling method in Appendix 8 (8.11).

This may reduce sampling costs when there are multiple sites discharging point source effluent releases to a Type B waterbody near each other.

The methods outlined in Appendix (8.11.2 and 8.11.3) shall be used to record DO concentrations used to determine daily diurnal DO (DDDO).

Any missed samples or deviations in sampling time should be accompanied by a written justification.

Records that DO measurements correspond to high and low tides in tidal systems.

The location of the sampling point, demonstrating that measurements have taken place downstream from the outflow point.

Results of daily DO monitoring and DDDO fluctuation calculations.

DO measurements have taken place at high and low tides in tidal systems.

DO measurements have taken place downstream from the outflow point.

The UoC has presented results of the DDDO calculations based on DO measurements collected in accordance with the methods outlined in Appendix 8.11.1 and 8.11.2.

Confirm the fluctuation level based on the DDDO calculation is ≤65% saturation level.

Written justifications were provided if there were any missed samples or deviations in the sampling time.

Methods to measure Total Suspended Solids (TSS) can be found in Appendix 8 (8.12).

Concentration of settleable solids (ml/L) can be measured by calculating the volume of solids that settles to the bottom of a conical cone (Imhoff cone) in one hour.

More sophisticated methods such as spectrophotometer readings can also be used to measure settable solids.

Details and location of the system used to treat effluent prior to discharge.

Evidence regular testing of TSS and settleable solids has taken place. Quarterly testing would demonstrate best practice.

Results from the testing of point source releases which demonstrate ≥65% of TSS are captured and the concentration of settleable solids in effluent water is consistently <3.3ml/L.

A treatment is in place and located prior to the point of discharge.

Results of testing from the UoC which confirm the treatment system captures ≥65% of suspended solids and that the concentration of settleable solids in effluent water is <3.3ml/L.