67_PAU5D_09

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67_PAU5D_09.pdf

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67_PAU5D_09.pdf (214.5 kb)

Abstract
A Bayesian length-based stock assessment model was applied to PAU 5D to estimate stock status and yield. The period 1989–96 was chosen as a reference period because in this period, exploitation rate and the recruited biomass were relatively stable.

The median mid-year recruited biomass estimate ranged from 172 t to 362 t depending on which runs were looked at (5th and 95th percentiles 114–533 t, across all base cases); the median spawning biomass estimate ranged from 371 t to 1390 t (271–2218 t). The median and upper percentiles for both current recruited and spawning biomass were less than the reference years 1989–96. The assessment indicated that the median exploitation rate ranged from 23.5% to about 45% (17–61%).

Five-year projections made with 2006 levels of MLS and catch show a 37–96% chance that recruited biomass will be greater than 2006 biomass (4–63% chance of decrease), a variable chance that it will be greater than the reference level, and variable chance that it will be above the minimum historical level. For spawning biomass there is a 75–95% chance of increase above the current level, 0–18% chance of exceeding the reference level, and a 2–24% chance of decreasing below the historical minimum. Median projected exploitation rate is 17.4–49% (11.4–65%).

The stock assessment results were equivocal. The Working Group noted that the future direction of recruited biomass was uncertain because of the range of possible results that were dependent on modelling decisions. It is not known if recent catch levels or the current TACC is sustainable, or if they are at levels which will allow the stocks to move towards a size that will support the maximum sustainable yield.

Document date
Sunday, 31 May 2009

Document type
V 1.3

File format
Adobe PDF

File size
214.5 kb

Reference number
2009

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M:\SCIPOL\Working Groups 2009\Plenary 2009\FINAL\MFish 2009 May Plenary\May 2009 - PDF\67_PAU5D_09.pdf

Uploaded date
Thursday, 11 June 2009

Search tags

Species: PAU;
Stock: PAU5D;

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