90_SWA_09

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90_SWA_09.pdf

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90_SWA_09.pdf (187.8 kb)

Abstract
Since the 2008 Plenary report was published, no new stock assessments have been competed for SWA stocks but a mid-term review has been completed for the SWA 1 AMP.

SWA 1
SWA 1 has been managed with a TACC of 3000 t since October 2002 under the AMP. CPUE indices have previously been considered to be unreliable for SWA 1. However, the SWA bottom and midwater trawl index prepared in 2009 seems to be consistent with indications of good recruitment in 1993, 1994 and 1997, with strong year classes contributing to increased catch rates over the ensuing few years. The WG concluded that this CPUE index may be indexing SWA 1abundance.

This index shows a period of stable or slowly declining CPUE from 1986 - 1992, followed by a rapid increase in CPUE to levels twice the long-term average by 1996. High catch rates continued to 1998, dipped in 1999 and rose to high levels again in 2000. Thereafter CPUE declined back to about half historic average levels, and appears to have remained stable at that level since 2004.

Catch curve analyses indicate that the average exploitation rate on silver warehou in the WCSI hoki fishery is probably less than the natural mortality rate, indicating that the stock is not being overfished.

Annual catches have averaged 1480 t since the increase in TACC to 3000t in 2002–03 and catches at this level are likely sustainable in the short to medium term. However, it is not known whether catches at the level of the TACC are sustainable. The state of the stock in relation to BMSY is unknown. This should be determined by the stock assessment being conducted.

Other stocks
No estimates of reference current absolute biomass are available.

In most years from 2000–01 to 2007–08 catches in SWA 3 and SWA 4 were well above the TACCs as fishers landed catches well in excess of ACE holdings. The sustainability of current TACCs and recent catch levels for these Fishstocks is not known, and it is not known if they 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
187.8 kb

Reference number
2009

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Uploaded from
M:\SCIPOL\Working Groups 2009\Plenary 2009\FINAL\MFish 2009 May Plenary\May 2009 - PDF\90_SWA_09.pdf

Uploaded date
Friday, 12 June 2009

Search tags

Species: SWA;
Stock: SWA1; SWA10; SWA3; SWA4;

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