60_OEO1-6_09

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60_OEO1-6_09.pdf

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60_OEO1-6_09.pdf (937.8 kb)

Abstract
New assessment results are reported in 2009 for Pukaki Rise black oreo. A preliminary assessment from 2008 is reported for Bounty Plateau smooth oreo (only MPD results).

OEO 1 black oreo and smooth oreo
The TACC was increased from 5033 t to 6044 t in 1992–93 under the adaptive management programme but reverted to 5033 t in 1998–99. It is not known if recent catch levels or the current TACC are sustainable or will allow the stock to move towards a size that will support the maximum sustainable yield. From 1 October 2007 the TACC was reduced to 2500 t.

Five year projections to estimate future mature and vulnerable biomass were subject to the same data problems as the biomass estimates. However, the Plenary concluded that catches at the level of the 2000–01 annual catch (1010 t) are probably not sustainable.

Pukaki Rise smooth oreo stock (part of OEO 6)
Current and virgin biomass for smooth oreo, on Pukaki Rise (part of OEO 6), were estimated for the first time in 2006. These biomass estimates are uncertain because of the lack of fishery-independent abundance estimates and the consequent reliance on commercial CPUE data, and because of the lack of biological parameter estimates specific to smooth oreo in this assessment area.

Model results suggest that mature virgin biomass is about 24 000 t with wide 90% confidence intervals (16 000 - 78 000 t). The Plenary noted that large stock sizes were unlikely, particularly because standardised CPUE has declined rapidly under catch levels that have been small relative to other smooth oreo fisheries. Smooth oreo life history parameters suggest a median long-term yield (MAY estimate) of about 550 t, which is lower than the current catch of 1300 t.

The estimated confidence intervals around virgin biomass were so wide that it is not possible to make a definitive statement about stock status. However, based on CPUE trends and the catch history, the Plenary agreed that current annual catch levels are unlikely to be maintained in the future.

No projections were made because of the uncertain biomass estimates.

Bounty Plateau smooth oreo stock (part of OEO 6)
Current and virgin biomass on Bounty Plateau (part of OEO 6) were estimated for the first time in 2008. Biomass estimates are uncertain because of the reliance on commercial CPUE data, biological parameter estimates are from oreo stocks, and because of contrasting biomass signals from using either a single or split CPUE indices.

The basecase model used the early and late period CPUE indices, and just the 1999 length frequency data, and current mature biomass was estimated to be 33% of a virgin biomass of 17 400 t (MPD estimate only). No MCMC runs or projections were made because of the uncertain biomass estimates.

Pukaki Rise black oreo stock (part of OEO 6)
An initial assessment was made for this stock in 2009. These biomass estimates are uncertain because of the lack of fishery-independent abundance estimates and the consequent reliance on commercial CPUE data, and because of the lack of biological parameter estimates specific to black oreo in this assessment area.

The basecase results suggest that mature virgin biomass was between 27 000 t and 117 000 t. The stock is currently estimated to be at 44% B0 but with high uncertainty (19-80% B0). Projections suggest that mature biomass is as likely as not to fall below 20% B0 within the next five years if catches are maintained at the 2007-08 level.

OEO 1 black oreo and smooth oreo
The TACC was increased from 5033 t to 6044 t in 1992–93 under the adaptive management programme but reverted to 5033 t in 1998–99. It is not known if recent catch levels or the current TACC are sustainable or will allow the stock to move towards a size that will support the maximum sustainable yield. From 1 October 2007 the TACC was reduced to 2500 t.

Document date
Sunday, 31 May 2009

Document type
V 1.3

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Adobe PDF

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937.8 kb

Reference number
2009

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M:\SCIPOL\Working Groups 2009\Plenary 2009\FINAL\MFish 2009 May Plenary\May 2009 - PDF\60_OEO1-6_09.pdf

Uploaded date
Thursday, 11 June 2009

Search tags

Species: OEO;
Stock: OEO1; OEO6;

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