66_PAU5B_09

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66_PAU5B_09.pdf

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66_PAU5B_09.pdf (219.5 kb)

Abstract
The stock assessment was updated in 2007. A Bayesian length-based stock assessment model was applied to PAU 5B to estimate stock status and yield. The agreed reference points used were the average spawning and recruited biomass, SAV and BAV respectively, from a reference period of 1985 to 1987. This period was chosen because in these years spawning and recruited biomass had stabilised following a ‘fishing down’ period that started in the early 1970s. The assessment also used the minimum spawning and recruited biomass observed in the model’s reconstruction: SMIN and BMIN.

The assessment suggests that current biomass estimates (S07 and B07) are well above the minimum reference levels SMIN and BMIN. This was true in all MPD sensitivity trials and in the MCMC. Projected biomass (S10 and B10) is highly likely to remain above these reference levels; in the MCMC projection, biomass never fell below BMIN or SMIN.

The assessment suggests that both spawning and recruited biomass are below the target levels SAV and BAV. Spawning biomass was estimated at 75% of SAV, (5th to 95th quantiles 66% to 85%) while recruited biomass was estimated as 87% of BAV (77% to 100%).

MCMC projections suggest that spawning biomass was more likely, (61%), to increase than decrease under current levels of total catch, and is likely to remain below SAV for the next three years. In contrast, recruited biomass shows a tendency to decrease, (64% probability), and remain below BAV. For recruited biomass, however, it cannot be concluded strongly that current biomass is less than the BAV reference level. The posterior touches 100% at the 95% confidence level. MPD sensitivity trials showed estimates of B07/BAV near 100% in several situations: when the CPUE dataset was removed, when the pre-1990 CPUE data were removed and when the lower-catch alternative series were used.

Document date
Sunday, 31 May 2009

Document type
V 1.3

File format
Adobe PDF

File size
219.5 kb

Reference number
2009

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M:\SCIPOL\Working Groups 2009\Plenary 2009\FINAL\MFish 2009 May Plenary\May 2009 - PDF\66_PAU5B_09.pdf

Uploaded date
Thursday, 11 June 2009

Search tags

Species: PAU;
Stock: PAU5B;

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