Indicator 4.2.1.8.4

The UoC should develop a procedure (e.g. SOP) to describe moribund collection and culling operations.

Moribund crustaceans should be collected using appropriate equipment to prevent further injuries and stress, e.g. hand net according to crustacean size.

Slaughtered moribund crustaceans should be considered for the calculations needed to demonstrate compliance with Indicator 4.2.1.4.

A contingency plan for emergency culling should be in place.

Monitoring for mortality is understood as visual observation of whether there is mortality at the site, e.g. observations of the crustaceans in feeding trays, observations of mortalities at the tank/pond discharge.

Possible causes that would justify no monitoring or removal of moribunds and mortality when spotted are severe bad weather, or a major equipment failure not related to poor maintenance.

Scrutiny of mortality records and cause determination is essential for preventing further avoidable deaths and improving overall crustacean health and welfare in aquaculture.

If on-site diagnosis is inconclusive, off-site laboratory diagnosis is required.

When designing the mortality monitoring process, the UoC should consider carrying out a post-mortem analysis for each mortality event, not necessarily every crustacean.

A statistically relevant number of crustaceans from the mortality event shall be analysed.

A statistically relevant number of crustaceans refers to a sample size that is large enough to yield meaningful and reliable results when conducting statistical analysis.

In other words, the sample size should be sufficient to accurately represent the population being studied and to draw valid conclusions from the data.

The specific size needed for statistical relevance depends on various factors such as the variability within the population, the desired level of confidence and the statistical methods being used.

Typically, larger sample sizes provide more reliable estimates and stronger evidence for drawing conclusions.

The designated veterinarian or aquatic animal health professional should assist the site in determining the appropriate sample size required for statistical analysis and must conduct all diagnosis.

Records:

The mortality monitoring process included in the HWMP incorporates the minimum required elements and is implemented.

Moribunds are collected when spotted and culled following responsible stunning and killing according to Criterion 4.2.3.

Implementation can be confirmed by cross-checking the frequency of collection and culling methods with records, information from employee interviews and observations.

Contingency plan for ‘treatment’ culling

Monitoring and removal of mortality in conformance with the frequency required.

Records, employee interviews and observations should demonstrate acceptable frequency.

McKay, H., & McAuliffe, W. (2024) Pre-slaughter mortality of farmed shrimp. ReThink Priorities: Technical report. 24pp.