Last updated on 28 October 2016

SUMMARY

SUMMARY

IDENTIFICATION

SCIENTIFIC NAME(s)

Micromesistius australis

SPECIES NAME(s)

Southern blue whiting, New Zealand southern blue whiting

Besides being found around the southern tip of South America, Southern blue whiting Micromesistius australis is found on the southern shelf of New Zealand, but is ocasionally considered to be a distinct subspecies – Micromesistius australis pallidus as opposed to Micromesistius australis australis.

Hanchet (1999) found significant differences in growth rates as well as on morphometric characteristics considering that the 4 stocks, which present distinct spawning grounds, should be assessed and managed separately: Auckland Islands (SBW 6A), Bounty Platform (SBW 6B), Campbell Island Rise (SBW 6I) and Pukaki Rise (SBW 6R). These 4 biological stocks are used by the Ministry for Primary Industries (MPI) for assessment and management purposes (MPI, 2015).


ANALYSIS

No related analysis

FISHSOURCE SCORES

Management Quality:

Management Strategy:

≥ 8

Managers Compliance:

NOT YET SCORED

Fishers Compliance:

10

Stock Health:

Current
Health:

≥ 8

Future Health:

NOT YET SCORED


FIPS

No related FIPs

CERTIFICATIONS

No related MSC fisheries

Fisheries

Within FishSource, the term "fishery" is used to indicate each unique combination of a flag country with a fishing gear, operating within a particular management unit, upon a resource. That resource may have a known biological stock structure and/or may be assessed at another level for practical or jurisdictional reasons. A fishery is the finest scale of resolution captured in FishSource profiles, as it is generally the scale at which sustainability can most fairly and practically be evaluated.

ASSESSMENT UNIT MANAGEMENT UNIT FLAG COUNTRY FISHING GEAR
Pukaki Rise NZ Pukaki Rise (SBW 6R) New Zealand Midwater trawls

Analysis

OVERVIEW

1.STOCK STATUS

STOCK ASSESSMENT

Last updated on 19 May 2010

For the purposes of stock assessment it is assumed that there are four stocks of southern blue whiting with fidelity within stocks: the Bounty Platform stock, the Pukaki Rise stock, the Auckland Islands stock, and the Campbell Island stock. The Pukaki Rise stock was last assessed in 2002 with an sSPA model.

SCIENTIFIC ADVICE

Last updated on 19 May 2010

For the Pukaki Rise stock the multiple sources of uncertainty in the acoustic surveys produce a range of stock biomass estimates which are unlikely to have been much impacted by the average catch level since 2002 (380 tonnes).

Reference Points

Last updated on 19 May 2010

On the latest assessment, conducted in 2002, estimates of B0 and B2000 were derived with a substantial amount of uncertainty:

B0 = 18,000 t – 54,000 t
B2000 = 8,000 t – 48,000 t

The stock assessment authors state though that “within these bounds, B2000 is greater than BMAY” (NZ Ministry Fisheries, 2009b).

CURRENT STATUS

Last updated on 19 May 2010

Based on the flat trajectory of the abundance indices over the period modelled in the assessment, recent catch levels do not appear to have had any impact on the biomass. Greater catches would be required to provide any contrast in the abundance indices, and therefore enable better estimates of stock size. This stock has been only lightly exploited since 1993, and the biomass bounds in 2000 were estimated as 8,000–48,000 tonnes, corresponding to 44-88% of B[~0 ~] and likely to be above the level that will support the MAY (Ministry of Fisheries, 2009b).

Trends

Last updated on 19 May 2010

Stock biomass trajectories estimated through separable sequential population analysis do not show clear trends between 1989 and 2000 but rather the effect of the uncertainty of the estimate of the acoustic parameter q.

2.MANAGEMENT QUALITY

MANAGEMENT

Last updated on 19 May 2010

No management plan is developed for the fishery. The New Zealand’s Ministry of Fisheries sets catch limits for each of the four stocks and a nominal catch of 8 t for the remainder of the EEZ. TACCs are set applying a constant mortality rate of 20% to the estimated Spawning Stock Biomass (SSB). The interim harvest strategy in place aims to keep the stock at or above B40% and foresees the implementation of a time-constrained rebuilding plan if the stock falls below the soft limit. The TAC revision is based on an estimate of the current annual yield (CAY) (MoF, 2011d). The TAC for 2010-2011 was set at 5,500 tonnes for the Pukaki Rise stock. Other management measures include a minimum mesh size in trawls, bottom trawl closures to protect sensitive seabed areas, and a ban on use of cables for net sounders (which can entangle some seabirds).

Recovery Plans

Last updated on 19 May 2010

Not applicable.

COMPLIANCE

Last updated on 19 May 2010

At Pukaki Rise the catches are far from the TACC in place in each year. Such “under-catch” can be a sign of poor stock condition, but scientists suggest a different interpretation for this fishery. It is thought to reflect low economic value and difficulty of timing and locating fish aggregations, according to stock assessment authors.The lower Pukaki Rise TACCs mean that fishers often find that time taken to locate aggregations is not justified (Ministry of Fisheries, 2009b).

IUU fishing is not thought to be a serious issue in the fishery although two convictions of vessel operators for area misreporting and dumping of fish have been reported in recent years (Ministry of Fisheries, 2009b).

3.ENVIRONMENT AND BIODIVERSITY

BYCATCH
ETP Species

Last updated on 19 May 2010

The report from Ministry of Forestry (2006) noted that Southern Blue Whiting (SBW) fisheries are known to make incidental captures of fur seals and New Zealand sea lions yet the available estimates of overall numbers are relatively low and do not give rise to concerns specific to the SBW fishery. Mitigation measures have reduced the number of seabird interactions with offshore trawls – bird-scaring devices are mandatory for trawlers and an industry-promoted voluntary Vessel Management Plan specifies further measures (Ministry of Fisheries, undated).

Other Species

Last updated on 19 May 2010

The available information suggests that SBW target fishing operations take relatively little bycatch of other finfish species (about 1% of total green weight catch based on observed and reported catch).

HABITAT

Last updated on 19 May 2010

Southern blue whiting is taken predominantly by mid-water trawl methods, although the gear might often come into contact with the seabed as catches can be made near the bottom. There is currently little information on the benthic effects of SBW trawling. A desktop study is underway to explore the data that is available from trawl catch and effort reporting.

Marine Reserves

Last updated on 19 May 2010

In November 2007 New Zealand established 17 areas closed to bottom trawling, comprising more than 1.1 million square kilometres of seabed, about 30% of New Zealand’s 200-mile fisheries zone. These protected areas include 88% of active hydrothermal vents and 52% of seamounts in the nation’s waters (Ministry of Fisheries, 2009c).

A network of Marine Protected Areas is being established, aimed at representing all of New Zealand’s major marine habitats and ecosystems and associated biodiversity. Protection measures may include restrictions or prohibitions on fishing activities (Ministry of Fisheries, 2009d).

FishSource Scores

SELECT SCORES

MANAGEMENT QUALITY

As calculated for 2013 data.

The score is ≥ 8.

There is an interim harvest strategy in place which aims to keep the stock at or above B40% and foresees the implementation of a time-constrained rebuilding plan if the stock falls below the soft limit (MoF, 2011d).

As calculated for 2010 data.

The score is 10.0.

This measures the Catch as a percentage of the Set TACC.

The Catch is 4.52 ('000 t). The Set TACC is 5.50 ('000 t) .

The underlying Catch/Set TACC for this index is 82.2%.

STOCK HEALTH:

As calculated for 2013 data.

The score is ≥ 8.

The stock was last assessed in 2002, with data up to 2000, and was estimated to be well above the management target (at 59% of B0). It has been only lightly exploited since 1993 and “the average catch level since 2002 (380 t) is unlikely to have made much impact on stock size” (Ministry of Fisheries, 2011).

No data available for biomass
No data available for biomass
To see data for catch and tac, please view this site on a desktop.
No data available for fishing mortality
No data available for fishing mortality
No data available for recruitment
No data available for recruitment
To see data for management quality, please view this site on a desktop.
To see data for stock status, please view this site on a desktop.
DATA NOTES
  1.  A general absence of available data – estimates of biomass and fishing mortality, fishing mortality and biomass reference points – prevents scores 1 and 5 from being computed. However, score 4 has been determined qualitatively, based on available information.
  2. As a single government agency is responsible for both stock assessment and management, management compliance is not an issue and no advised TAC is available (score 2 cannot be computed).
  3. Since 2000/2001, each fishing year starts in April and ends in March of the following year; accordingly, the 2010 data refer to the April 2010 – March 2011 fishing year.
  4. There are no quantitative estimates of by-catch so they are not included in the assessment.

Download Source Data

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Fishery Improvement Projects (FIPs)

No related FIPs

Certifications

Marine Stewardship Council (MSC)

No related MSC certifications

Sources

Credits
  1. Hanchet, S. 1999. Stock structure of southern blue whiting (Micromesistius australis) in New Zealand waters, New Zealand Journal of Marine and Freshwater Research, 1999, Vol. 33: 599-609http://www.tandfonline.com/doi/pdf/10.1080/00288330.1999.9516903
  2. Ministry for Primary Industries (MPI), 2015. Fisheries Assessment Plenary May 2015: Stock Assessments and Stock Status, Southern blue whiting (SBW), 1257-1287 pp.http://fs.fish.govt.nz/Doc/23895/86_SBW2015_FINAL.pdf.ashx
  3. Ministry of Fisheries, 2009a. Fishery: Southern Blue Whiting. http://fs.fish.govt.nz/Page.aspx?pk=5&tk=96&ey=2010&fpid=49
  4. Ministry of Fisheries, 2009b. Report from the Fisheries Assessment Plenary, May 2009: stock assessment and yield estimates. Ministry of Fisheries, Wellington, New Zealand.http://fs.fish.govt.nz/Doc/21791/93_SBW_09.pdf.ashx
  5. Ministry of Fisheries, 2009c. Benthic Protected Areas.http://fs.fish.govt.nz/Page.aspx?pk=68&tk=278
  6. Ministry of Fisheries, 2009d. Marine Protected Areas.http://fs.fish.govt.nz/Page.aspx?pk=68&tk=280
  7. Ministry of Fisheries, 2011. Southern Blue Whiting (SBW). 28 pp.http://fs.fish.govt.nz/Doc/22790/87_SBW_2011.pdf.ashx
  8. Ministry of Fisheries , undated. Environmental Issue: Deepwater trawl (vessels over 28 metres) - Seabird interactionshttp://fs.fish.govt.nz/Page.aspx?pk=116&dk=602
References

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    Southern blue whiting - Pukaki Rise

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