Description
Measure signed days from tagged-fish release to recorded recapture.
Fish records distinguish morphometric length definitions, relative image scales, annulus labels, detection times and survey-effort geometry. A supplied conversion factor need not apply across species or sizes. Local labels, ratios and nominal swept areas organize observations without identifying a fish, determining age or estimating abundance.
Measure signed days from tagged-fish release to recorded recapture.
When to use this tool
Use Fish Tag Release Recapture Date Gap when you already have releaseDate, recaptureDate and need to measure signed days from tagged-fish release to recorded recapture.
How to use the tool and how it works
- Enter releaseDate, recaptureDate. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read signedCalendarDays. Use the output convention below.
Parse real UTC dates; return recaptureDate-releaseDate in days.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| releaseDate | Release Date | Required. Text; maximum UTF-16 length 8192. Real proleptic Gregorian YYYY-MM-DD; four-digit years 0000-9999 accepted. |
| recaptureDate | Recapture Date | Required. Text; maximum UTF-16 length 8192. Real proleptic Gregorian YYYY-MM-DD; four-digit years 0000-9999 accepted. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| signedCalendarDays | Recapture-release date; negative gaps remain visible rather than being corrected. | Required. Safe integer. |
{
"input": {
"releaseDate": "2026-10-28",
"recaptureDate": "2026-11-01"
},
"output": {
"signedCalendarDays": 4
}
}Limitations and assumptions
- Negative gaps are retained; no actual release/recapture, identity, survival or movement is verified.
- 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.
Alternative or Complementary methods
Inspect original specimens, images, reference definitions and survey logs when verifying observations. Use a complete species-appropriate measurement or population method for age, abundance or condition questions; local scales and effort terms preserve only their stated basis.
References
Similar or alternative tools
- Fish Tag Detection Gap
Measure a nonnegative gap between supplied fish-tag detections.
- Fish Trawl Swept Area Factor
Calculate nominal swept area from tow distance, width and supplied coverage fraction.