Fry Stocking
Invert serial expected survival to a rounded initial fry count; an expectation-based plan, not a probability guarantee or density recommendation.
Description
Stocking backward from a desired survivor count uses the product of successive survival fractions.
Stocking backward from a desired survivor count uses the product of successive survival fractions. Rounding initial fish upward accounts for indivisible animals but does not remove survival uncertainty.1
Invert serial expected survival to a rounded initial fry count; an expectation-based plan, not a probability guarantee or density recommendation.
When to use Fry Stocking
Use this tool to invert serial expected survival to a rounded initial fry count; an expectation-based plan, not a probability guarantee or density recommendation.
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 Fry Stocking 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 targetHarvestFishCount, conditionalSurvivalFractions using the field table and calculation rules, then run the tool.
- Read overallExpectedSurvivalFraction, requiredInitialFryCount, expectedHarvestFishCount. 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 |
|---|---|---|---|
| targetHarvestFishCount | Target harvest fish count | integer | Required |
| conditionalSurvivalFractions | Conditional survival fractions | list of number | Required |
Enter a nonnegative integer target and a nonempty list of stage survival fractions greater than zero through one. The combined product must remain positive. Return its value, the upward-rounded safe integer initial count and expected survivors from that count.
combinedSurvival=ΠstageSurvival; initialCount=ceil(targetSurvivors/combinedSurvival) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| overallExpectedSurvivalFraction | Overall expected survival fraction | number |
| requiredInitialFryCount | Required initial fry count | number |
| expectedHarvestFishCount | Expected harvest fish count | number |
{
"input": {
"targetHarvestFishCount": 1000,
"conditionalSurvivalFractions": [
0.8,
0.5
]
},
"output": {
"overallExpectedSurvivalFraction": 0.4,
"requiredInitialFryCount": 2500,
"expectedHarvestFishCount": 1000
}
}Limitations and assumptions
Survival is an expectation under the supplied stages rather than a guarantee. Density effects, correlated mortality and uncertainty are excluded; underflow of the product is rejected.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Broodstock Requirement: Plan broodstock counts from supplied fecundity, spawning participation and fry survival; expected productivity is not genetic, welfare or spawn-success certification. For a complementary task, use 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.
References
-
Fry Stocking — tool.io
Similar or alternative tools
- Broodstock Requirement
Plan broodstock counts from supplied fecundity, spawning participation and fry survival; expected productivity is not genetic, welfare or spawn-success certification.
- 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.