Cannibalism Loss Estimate

Bound possible cannibalism losses using confirmed cases and unexplained missing inventory after other verified losses; does not assign unexplained losses to cannibalism.

Description

Inventory reconciliation separates confirmed cannibalism from fish whose fate remains unexplained.

Inventory reconciliation separates confirmed cannibalism from fish whose fate remains unexplained. The missing balance gives an upper bound without automatically labeling every missing fish as cannibalized.^[1]

Bound possible cannibalism losses using confirmed cases and unexplained missing inventory after other verified losses; does not assign unexplained losses to cannibalism.

When to use Cannibalism Loss Estimate

Use this tool to bound possible cannibalism losses using confirmed cases and unexplained missing inventory after other verified losses; does not assign unexplained losses to cannibalism.

Prepare the cohort, water, feed or equipment measurements for one consistent operating period. Confirm nitrogen reporting bases, dry/wet masses, flow units and supplied design assumptions.

How to use Cannibalism Loss Estimate and understand its results

Prepare the cohort, water, feed or equipment measurements for one consistent operating period. Confirm nitrogen reporting bases, dry/wet masses, flow units and supplied design assumptions.
Enter initialFishCount, remainingFishCount, verifiedOtherLossCount, confirmedCannibalismCount using the field table and calculation rules, then run the tool.
Read unexplainedMissingCount, minimumCannibalismLossPercent, maximumPossibleCannibalismLossPercent. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
initialFishCount	Initial fish count	integer	Required
remainingFishCount	Remaining fish count	integer	Required
verifiedOtherLossCount	Verified other loss count	integer	Required
confirmedCannibalismCount	Confirmed cannibalism count	integer	Required

Enter a positive integer initial stock and nonnegative integer remaining, other-loss and confirmed-cannibalism counts. Accounted fish cannot exceed initial stock. Return unexplained count and confirmed-only and all-unexplained bounds.

unexplained=initial−remaining−otherLosses−confirmed; lower%=100 confirmed/initial; upper%=100(confirmed+unexplained)/initial

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
unexplainedMissingCount	Unexplained missing count	number
minimumCannibalismLossPercent	Minimum cannibalism loss percent	number
maximumPossibleCannibalismLossPercent	Maximum possible cannibalism loss percent	number

json

{
  "input": {
    "initialFishCount": 1000,
    "remainingFishCount": 900,
    "verifiedOtherLossCount": 60,
    "confirmedCannibalismCount": 10
  },
  "output": {
    "unexplainedMissingCount": 30,
    "minimumCannibalismLossPercent": 1,
    "maximumPossibleCannibalismLossPercent": 4
  }
}

Limitations and assumptions

The bounds depend on complete, nonoverlapping records. This does not identify a cause for missing fish or measure a size-based cannibalism risk.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Grading Size Variation: Calculate weighted population size CV and grading counts from weight/frequency observations; bins are left-closed at boundaries and no cannibalism threshold is inferred. For a complementary task, use Fry Stocking: Invert serial expected survival to a rounded initial fry count; an expectation-based plan, not a probability guarantee or density recommendation.

References

Cannibalism Loss Estimate — tool.io

Similar or alternative tools

Grading Size Variation
Calculate weighted population size CV and grading counts from weight/frequency observations; bins are left-closed at boundaries and no cannibalism threshold is inferred.
Fry Stocking
Invert serial expected survival to a rounded initial fry count; an expectation-based plan, not a probability guarantee or density recommendation.