Description
Compute positive transectLength times stripWidth as sampledArea.
Fisheries sampling effort can be expressed as net-hours, area-hours, or another declared survey unit. Exclusions and partial operation change the counted effort without automatically correcting catchability or sample bias.
Compute positive transectLength times stripWidth as sampledArea.
When to use this tool
Use Fish School Transect Density Term when you need a reproducible effort component under a supplied survey convention.
How to use the tool and how it works
- Enter fish, transectLength, stripWidth, detectionFraction. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read sampledArea, observedDensity, adjustedDensity. Use the output convention below.
Compute positive transectLength times stripWidth as sampledArea. Divide fish count by area for observedDensity and by area times detectionFraction in (0, 1] for adjustedDensity.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| fish | Fish | Required. Safe integer; minimum 0. |
| transectLength | Transect Length | Required. Finite number; strictly above 0. |
| stripWidth | Strip Width | Required. Finite number; strictly above 0. |
| detectionFraction | Detection Fraction | Required. Finite number; maximum 1; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| sampledArea | Sampled Area | Required. Finite number. |
| observedDensity | Observed Density | Required. Finite number. |
| adjustedDensity | Adjusted Density | Required. Finite number. |
{
"input": {
"fish": 100,
"transectLength": 50,
"stripWidth": 2,
"detectionFraction": 0.5
},
"output": {
"sampledArea": 100,
"observedDensity": 1,
"adjustedDensity": 2
}
}Limitations and assumptions
- Output uses fish per square length unit; detection is supplied rather than estimated, and the calculation does not validate survey design or school detection.
- 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
Use the complete survey design and suitable detection or catchability methods when estimating population abundance.
References
Similar or alternative tools
- Gillnet Catch Per Area Hour Term
Multiply positive netLength, netHeight, hours, and activeFraction in (0, 1] for areaTimeEffort.
- Fish Length Frequency One Bin Density
Return count/total, that fraction divided by bin width, and count/sampledFraction.