Description
Return second minus first age, their mean, and mean minus referenceAge.
Age and growth records compare reader estimates, increments, lengths, and observation intervals. A numeric difference or back-calculation depends on the chosen origin and model rather than establishing the animal's true age.
Return second minus first age, their mean, and mean minus referenceAge.
When to use this tool
Use Otolith Two Reader Age Gap when you need one supplied age or growth-record component.
How to use the tool and how it works
- Enter firstAge, secondAge, referenceAge. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read signedGap, meanAge, meanReferenceGap. Use the output convention below.
Require nonnegative integer reader ages and nonnegative referenceAge. Return second minus first age, their mean, and mean minus referenceAge.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| firstAge | First Age | Required. Safe integer; minimum 0. |
| secondAge | Second Age | Required. Safe integer; minimum 0. |
| referenceAge | Reference Age | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| signedGap | Signed Gap | Required. Safe integer. |
| meanAge | Mean Age | Required. Finite number. |
| meanReferenceGap | Mean Reference Gap | Required. Finite number. |
{
"input": {
"firstAge": 4,
"secondAge": 6,
"referenceAge": 4.5
},
"output": {
"signedGap": 2,
"meanAge": 5,
"meanReferenceGap": 0.5
}
}Limitations and assumptions
- All ages share one unit; agreement does not establish true age, reader accuracy, increment periodicity, or a validated reference.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Review aging validation, measurement landmarks, sampling, and the species-specific growth assumptions separately.
References
Similar or alternative tools
- Otolith Edgeage Reference Offset
Add nonnegative integer countedIncrements, edgeFraction in [0, 1], and signed suppliedReferenceOffset for ageEquivalent.
- Otolith Radius Fish Length Back Calc Term
Return interceptLength + (captureLength-interceptLength) × earlierRadius/captureRadius.