# Presentation: 687090

## White Hake

- Base
- Similar to 2002 VPA results
- FractionSamples
- Introduces uncertainty in age-length key
- AgeError
- Ageing imprecise
- FractionandAgeError
- Purpose: test models under high ageing uncertainty and bias

## White hake basic setup

- Years 1989-2001 (12 years)
- Ages 1-30, 9+
- Lengths 1-200 cm
- 2 market categories
- 3 surveys
- (CVs vary by age, 20%-50%)
- CV on landings 5%
- Growth stdevs 5.0 initial, 1.0 projection
- Von B params 189, 0.081, 0.062
- 50% Mature ~35 cm
- Selectivity flat-topped, 50% selected 39 cm
- M = 0.2
- F high all years (0.5-2.1)

## White hake test cases

- Fractionsamples
- 40% of lengths used to create ALK
- AgeError
- Adds uncertainty but not much bias

## White Hake

|  | BASE | Age Error | Fraction | Age Err & Fraction |
| --- | --- | --- | --- | --- |
| AIM | SSB: unbiased
F: slightly - |  |  |  |
| ASPIC | One way trip problem |  |  |  |
| SCALE | SSB: slight bias
F: ++ in year 1 |  |  |  |
| VPA | SSB: unbiased
F: unbiased |  |  |  |
| ASAP | SSB: unbiased
F: unbiased |  |  |  |

## White Hake

|  | BASE | Age Error | Fraction | Age Err & Fraction |
| --- | --- | --- | --- | --- |
| AIM | SSB: unbiased
F: unbiased | SSB: unbiased
F: slightly - | Same as base | Same as Age Error |
| ASPIC | One way trip problem |  |  |  |
| SCALE | SSB: slight bias
F: ++ in year 1 |  |  |  |
| VPA | SSB: unbiased
F: unbiased |  |  |  |
| ASAP | SSB: unbiased
F: unbiased |  |  |  |

## AIM

## White Hake

|  | BASE | Age Error | Fraction | Age Err & Fraction |
| --- | --- | --- | --- | --- |
| AIM | SSB: unbiased
F: unbiased | SSB: unbiased
F: slightly - | Same as base | Same as Age Error |
| ASPIC | One way trip problem |  |  |  |
| SCALE | SSB: slight bias
F: ++ in year 1 | Same as base |  |  |
| VPA | SSB: unbiased
F: unbiased |  |  |  |
| ASAP | SSB: unbiased
F: unbiased |  |  |  |

## SCALE

## White Hake

|  | BASE | Age Error | Fraction | Age Err & Fraction |
| --- | --- | --- | --- | --- |
| AIM | SSB: unbiased
F: unbiased | SSB: unbiased
F: slightly - | Same as base | Same as Age Error |
| ASPIC | One way trip problem |  |  |  |
| SCALE | SSB: slight bias
F: ++ in year 1 | Same as base |  |  |
| VPA | SSB: unbiased
F: unbiased | SSB: -20 to +60%
F: -20 to +60% | SSB: - 40 to +20%
F: +/- 50% | Same as Age Error |
| ASAP | SSB: unbiased
F: unbiased |  |  |  |

## VPA (SSB)

## VPA (FAA)

## White Hake

|  | BASE | Age Error | Fraction | Age Err & Fraction |
| --- | --- | --- | --- | --- |
| AIM | SSB: unbiased
F: unbiased | SSB: unbiased
F: slightly - | Same as base | Same as Age Error |
| ASPIC | One way trip problem |  |  |  |
| SCALE | SSB: slight bias
F: ++ in year 1 | Same as base |  |  |
| VPA | SSB: unbiased
F: unbiased | SSB: -20 to +60%
F: -20 to +60% | SSB: - 40 to +20%
F: +/- 50% | Same as Age Error |
| ASAP | SSB: unbiased
F: unbiased | SSB: unbiased
F: slightly - | Same as base | Same as Age Error |

## ASAP

## VPA vs ASAP  NAA

## VPA vs ASAP  NAA

## Precision (SSB and F)

- AIM: ~ 0.1-0.2, did not vary by case
- SCALE: ~0.1, did not vary by case
- VPA*: <0.2 (poor ages>7)
- ASAP: ~0.05, did not vary
- *VPA CVs are for age-specific SSB, F

## White Hake Conclusions

- Models that do not fit age data (AIM, SCALE) were robust to aging errors (assuming correct von B for SCALE)
- Bias pattern similar for VPA and ASAP, but magnitude was far less for ASAP