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Spanner Crab

Ranina ranina

  • Jason McGilvray (Department of Agriculture and Fisheries, Queensland)
  • Daniel Johnson (Department of Primary Industries, New South Wales)
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Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
Queensland, New South Wales East Coast SCF, OTLF Sustainable Target CPUE, target fishery independent CPUE
OTLF
Ocean Trap and Line (NSW)
SCF
Spanner Crab Fishery (QLD)
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Stock Structure

Mitochondrial DNA analysis indicates that Spanner Crabs on the east coast of Australia comprise a single biological stock1.

Here, assessment of stock status is presented at the biological stock level—East Coast.

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Stock Status

East Coast

The East Coast Spanner Crab stock is shared between Queensland and New South Wales, with Queensland accounting for the largest harvest (~90 per cent based on 2015 reported harvest).

In 2015, total catch of Spanner Crabs was ~30 per cent higher than 2014, but remained within the bounds of the total harvests realised between 2009 and 2014 (Figure 2). This increased total catch was due to a small increase in effort combined with a slightly improved catch per unit effort (CPUE). Despite this, the 2015 catch is still significantly reduced compared to the mid-1990s2. These reductions in catch can be attributed to large reductions in fishing effort (for Queensland; 3–3.5 million pot-lifts in the mid-1990s compared to 1.1 million pot-lifts in 2015), caused through fishery economics, social factors and the loss of fishing area and removal of endorsements with the creation of marine parks in north east New South Wales.

The standardised catch rate of Spanner Crabs from an annual fishery independent survey (in Queensland 2000–15 and in New South Wales 2006–15) has increased since 20002. The time series of survey data shows significant low points between 2001 and 2003, and a gradual increase between 2005 and 2015. In 2015, the survey catch rate was above the target reference point. The survey also shows consistent numbers of small crabs (below the minimum legal size), indicating continued recruitment to the fishery2. These fishery independent indicators suggest an increasing Spanner Crab biomass.

In Queensland, the 2015 commercial fishery standardised catch rate value was below the target reference point, however the value is similar to the one calculated for the years 2000–032. Large reductions in effort between 2000 and 2015 have offset the reductions in harvest over the same time period, and contributed to this result. The nominal catch rate from the New South Wales commercial fishery in 2011–12 financial year was within historical levels2.

The above evidence indicates that the biomass of this stock is unlikely to be recruitment overfished.

Fishing pressure in Queensland is controlled through a total allowable commercial catch (TACC). The TACC is set biennially, using an empirical model based on fishery catch rates (Queensland) and fishery-independent catch rates (Queensland and New South Wales)3. In 2015, the pooled index (the arithmetic mean of the commercial and survey indices) recommended the commercial quota remain at the base level (1631 tonnes [t]) for the June 2016–May 2018 period.

In New South Wales, fishing mortality in the northern zone (Angourie Pt – New South Wales/Queensland border) is controlled through an interim Total Commercial Access Level (ITCAL) of 164.1 t, with catch allocations based on current shareholdings, effective from 1 July 2015. The ITCAL was set a level commensurate with current catches. A total allowable catch for the fishery will be determined and a fishery-wide catch quota will commence July 2017. Given the small proportion of total landings taken in New South Wales, it is unlikely that fishing of this part of the stock is having a detrimental effect on the entire East Coast stock4.

Fishing pressure from the recreational sector is negligible. The estimated harvest by recreational fishers in Queensland is less than one per cent of reported commercial catch, while the estimated recreational catch from New South Wales is unknown (Table 3). The most recent recreational survey completed in New South Wales did not report the capture of any Spanner Crabs5. However, the survey methodology is potentially too broad to pick up species, such as Spanner Crabs, which tend to be caught by ‘niche’ fisheries.

The spawning biomass of the East Coast stock is protected through minimum size limits, aimed at allowing mature individuals to spawn at least once, and temporal (spawning) closures to protect spawning animals. Egg-bearing females are rarely caught and cannot be retained. These regulations apply to both commercial and recreational fishers. Spanner Crabs are caught through entanglement and there is evidence that limb damage during removal from the fishing gear leads to increased mortality of discarded crabs6, which may offset the benefits of the minimum legal size. Current fishing practices in New South Wales and Queensland aim to minimise damage to discarded crabs to limit such post release mortality6,7.

The above evidence indicates that the current level of fishing pressure is unlikely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, the East Coast biological stock is classified as a sustainable stock.

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Biology

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Spanner Crab 10–15 years; 160 mm RCL  Females: 70 mm RCL

Spanner Crab biology8,9

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Distributions

Distribution of reported commercial catch of Spanner Crab

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Tables

Fishing methods
Queensland New South Wales
Commercial
Tangle Net
Recreational
Tangle Net
Management methods
Method Queensland New South Wales
Commercial
Daily catch limits
Egg bearing females protected
Gear restrictions
Limited entry
Size limit
Spatial closures
Temporal closures
Total allowable catch
Vessel restrictions
Indigenous
Section 31 (1)(c1), Aboriginal cultural fishing authority
Recreational
Bag/possession limits
Egg bearing females protected
Gear restrictions
Size limit
Spatial closures
Temporal closures
Active vessels
Queensland New South Wales
57 in SCF 19 in OTLF
OTLF
Ocean Trap and Line (NSW)
SCF
Spanner Crab Fishery (QLD)
Catch
Queensland New South Wales
Commercial 1.18Kt in SCF 109.27t in OTLF
Indigenous < 1 per cent of recreational None
Recreational < 1 per cent of commercial Unknown
OTLF
Ocean Trap and Line (NSW)
SCF
Spanner Crab Fishery (QLD)

Indigenousa,b,c

a In Queensland, under the Fisheries Act 1994, Indigenous fishers are able to use prescribed traditional and non-commercial fishing apparatus in waters open to fishing. Size and bag limits and seasonal closures do not apply to Indigenous fishers. Further exemptions to fishery regulations can be obtained through permits

b Aboriginal Cultural Fishing Interim Access Arrangement allows an Aboriginal fisher in New South Wales to take in excess of a recreational bag limit in certain circumstances, for example, if they are doing so to provide fish to other community members who cannot harvest themselves.

c Aboriginal cultural fishing authority - the authority that indigenous persons can apply for to take catches outside the recreational limits under the Fisheries Management Act 1994 (NSW), Section 37 (1)(c1), Aboriginal cultural fishing authority.

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Catch Chart

Commercial catch of Spanner Crab

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Effects of fishing on the marine environment

  • Undersize and berried Spanner Crabs are the most common bycatch of this fishery, and fishers, managers and researchers have developed specific regulations and industry best practice guidelines to minimise post release mortality7. These include gear design and amount, vessel manning requirements and regulated fishing practices, such as the immediate removal and return to the water of unwanted crabs. Spanner Crabs are targeted using passive gear. Bycatch is minimal and interactions with protected species are rare6.
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Environmental effects on Spanner Crab

  • The impact of environmental factors on Spanner Crab stocks is unknown.
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References

  1. 1 Brown, I, Kirkwood, J, Gaddes, S, Dichmont, C and Ovenden, J 1999, Population dynamics and management of Spanner Crabs (Ranina ranina) in southern Queensland, project report QO99010, Queensland Department of Primary Industries, Brisbane.
    https://books.google.com.au/books/about/Population_Dynamics_and_Management_of_Sp.html?id=KobWQgAACAAJandredir_esc=yandhl=en
  2. 2 Campbell, MJ, O’Neill, MF, McGilvray, JG 2016 Queensland Spanner Crab Fishery: commercial quota setting for June 2016–May 2018. Department of Agriculture and Fisheries, Queensland.
  3. 3 O’Neill, MF, Campbell, AB, Brown, IW and Johnstone, R 2010, Using catch rate data for simple cost-effective quota setting in the Australian Spanner Crab (Ranina ranina) Fishery, ICES Journal of Marine Science, 67: 1538–1552.
  4. 4 Rowling, K, Hegarty, A and Ives, M 2010, Status of fisheries resources in NSW 2008/09, New South Wales Industry and Investment, Cronulla.
  5. 5 West, LD, Stark, KE, Murphy, JJ, Lyle, JM and Ochwada-Doyle, FA 2015, Survey of recreational fishing in New South Wales and the ACT, 2013/14. Fisheries Final Report Series No. 149. NSW Department of Primary Industries, Wollongong.
  6. 6 Kennelly, SJ, Watkins, D and Craig, JR 1990, Mortality of discarded spanner crabs Ranina ranina (Linnaeus) in a tangle-net fishery: laboratory and field experiments, Journal of Experimental Marine Biology and Ecology, 140: 39–48.
  7. 7 Brown, IW, Dunning, MC, Hansford, S and Gwynne, L 2003, Ecological assessment—Queensland Spanner Crab Fishery, Queensland Department of Primary Industries, Brisbane.
  8. 8 Brown, IW 1986, Population Biology of the Spanner Crab (Ranina ranina) in south-east Queensland, unpublished report, Queensland Department of Primary Industries, Brisbane.
  9. 9 Baylon, JC and Tito, OD 2012, Reproductive biology of the Red Frog Crab, Ranina ranina (Linnaeus, 1758) (Crustacea: Decapoda: Raninidae) from southwestern Mindanao, Philippines, Asian Fisheries Science, 25: 113–123.
  10. 10 Webley, J, McInnes, K, Teixeira, D, Lawson, A and Quinn R 2015, Statewide Recreational Fishing Survey 2013–14, Department of Agriculture and Fisheries, Queensland.

Archived reports

Click the links below to view reports from other years for this fish.