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School Shark

Galeorhinus galeus

  • Nic Marton (Australian Bureau of Agricultural and Resource Economics and Sciences)
  • Corey Green (Department of Economic Development, Jobs, Transport and Resources, Victoria)
  • Jeremy Lyle (Institute for Marine and Antarctic Studies, University of Tasmania)
  • Matias Braccini (Department of Fisheries, Western Australia)
  • Paul Rogers (South Australian Research and Development Institute)
  • Vic Peddemors (Department of Primary Industries, New South Wales)

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Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
Tasmania Southern Australia SF Overfished Estimate of biomass (relative pup production)
SF
Scalefish Fishery (TAS)
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Stock Structure

School Shark has a broad distribution throughout temperate waters of the eastern North Atlantic, western South Atlantic, and north-eastern and south-eastern Pacific, off South Africa, New Zealand and southern Australia. There is some uncertainty about the stock structure for School Shark1,2 however, a recent genetic study found there is likely to be one genetic stock spread between Australia and New Zealand3. A single Australian biological stock is assumed for management purposes. Insufficient data exist to support more complex stock structure analysis1.

Here, assessment of stock status is presented at the biological stock level—Southern Australian.

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Stock Status

Southern Australia

Assessments since 1991 have consistently estimated that the School Shark stock is less than 20 per cent of the unfished biomass. School Shark is currently taken as incidental catch in fisheries targeting Gummy Shark and this ongoing, unavoidable bycatch complicates efforts to minimise School Shark fishing mortality. However, historically they were a target species in southern Australia and catches were much larger.

A full stock assessment for School Shark was published in 20093. In 2012, the 2009 assessment was rerun with additional catch data between 2009 and 20124. There are concerns about the ability of the stock assessment to reliably estimate the state of the stock. The assessment incorporates a number of fishery-dependent (catch and effort) and fishery-independent (survey) data series. However, given the low total allowable catches (TAC) in recent years (potentially affecting quota availability, and the accurate reporting of catch and discards), the avoidance behaviour reported by fishers, and recent introduction of spatial closures predominantly off South Australia that prohibit the use of gillnets, the catch per unit effort data may be less reliable as an index of abundance in recent years5, therefore limiting the ability of the model to accurately resolve the stock status.

The most recent assessment3 estimated that biomass was 12 per cent of the unfished level (2008). The stock is considered to be recruitment overfished6. Under a zero catch scenario, the stock was projected to rebuild to B20 (the limit reference point) within 23 years. However, even the setting of a TAC that would allow rebuilding within 32 years (125 tonnes [t]) would severely constrain Commonwealth fishers that target Gummy Shark. Catch scenarios up to 250 t were projected to allow recovery of the stock within three generations (66 years), but catches of 275 t or greater could not be sustained4. Total landed catch (excluding discards) across all jurisdictions was 189 t in 2015.

Industry members have reported signs of increasing availability of School Shark, and that School Shark are becoming harder to avoid5. This is supported by preliminary survey work currently being conducted by the Institute for Marine and Antarctic Studies in pupping areas adjacent to Tasmania7. The results are consistent with the 2009 stock assessment3, which suggested that adult biomass levels have stabilised or begun recovering. The results are also consistent with the 2012 stock assessment model results, which predict that rebuilding is likely to be occurring and that catches of 250 t or less would allow rebuilding, provided that gear selectivity and spatial and temporal distribution of catches remain similar to those in 2011. However, it is unclear whether the level of fishing mortality has been adequately reduced to allow the stock to recover from its recruitment overfished state6. Measurable improvements in biomass are yet to be detected.

On the basis of the evidence provided above, the Southern Australian biological stock is classified as an overfished stock.

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Biology

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
School Shark 50 years; ~1 750 mm TL , 32.5 kg 12–16 years; mean length at female maturity and pupping are 1 240 and 1 420 mm TL, respectively

School Shark biology8–11

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Distributions

Distribution of reported commercial catch of School Shark

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Tables

Fishing methods
Tasmania
Commercial
Various
Recreational
Hand Line, Hand Reel or Powered Reels
Demersal Longline
Gillnet
Management methods
Method Tasmania
Commercial
Gear restrictions
Size limit
Spatial closures
Trip limits
Recreational
Bag limits
Size limit
Spatial closures
Trip limits
Active vessels
Tasmania
10 in SF
SF
Scalefish Fishery (TAS)
Catch
Tasmania
Commercial 1.29t in SF
Indigenous Unknown
Recreational Unknown
SF
Scalefish Fishery (TAS)

Recreationala,b Indigenousc–h

a The Australian Government does not manage recreational fishing in Commonwealth waters. Recreational fishing in

Commonwealth waters is managed by the state or territory immediately adjacent to those waters, under its management

regulations.

b In Tasmania, a recreational licence is required for fishers using dropline or longline gear, along with nets, such as gillnet or beach seine.

c The Australian Government does not manage non-commercial Indigenous fishing in Commonwealth waters, with the

exception of the Torres Strait. In general, non-commercial Indigenous fishing in Commonwealth waters is managed by the state

or territory immediately adjacent to those waters.

d In Victoria, regulations for managing recreational fishing are also applied to fishing activities by Indigenous people. Recognised Traditional Owners (groups that hold native title or have agreements under the Traditional Owner Settlement Act 2010 [Vic]) are exempt (subject to conditions) from the requirement to hold a recreational fishing licence, and can apply for permits under the Fisheries Act 1995 (Vic) that authorise customary fishing (for example, different catch and size limits or equipment). The Indigenous category in Table 3 refers to customary fishing undertaken by recognised Traditional Owners. In 2015, there were no applications for customary fishing permits to access School Shark.

e 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.

f The Aboriginal cultural fishing authority is the authority that Indigenous persons can apply to take catches outside the

recreational limits under the Fisheries Management Act 1994 (NSW), Section 37 (1)(c1), Aboriginal cultural fishing authority.

g Subject to the defence that applies under Section 211 of the Native Title Act 1993 (Cth), and the exemption from a requirement to hold a Victorian recreational fishing licence, the non-commercial take by indigenous fishers is covered by the same arrangements as that for recreational fishing.

h In Tasmania, Indigenous people engaged in aboriginal fishing activities in marine waters are exempt from holding recreational fishing licences, but must comply with all other fisheries rules as if they were licensed. Additionally, recreational bag and possession limits also apply. If using pots, rings, set lines or gillnets, Aborigines must obtain a unique identifying code (UIC). The policy document Recognition of Aboriginal Fishing Activities for issuing a Unique Identifying Code (UIC) to a person for Aboriginal Fishing activity explains the steps to take in making an application for a UIC.

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Catch Chart

Commercial catch of School Shark

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Effects of fishing on the marine environment

  • Interactions with marine mammals (Australian Sea Lions, Long-nosed Fur Seals, New Zealand Fur Seals and dolphins) in some gillnet fisheries continue to be an issue. Mitigation actions that have been implemented include spatial and temporal closures, increased monitoring, and implementation of the Australian Sea Lion Management Strategy14 and Dolphin Strategy15. The Australian Fisheries Management Authority has closed areas where most interactions occur and increased observer coverage to 100 per cent in adjacent areas. These management measures were revised through the Dolphin Strategy for the 2014–15 fishing season15.
  • Offal management strategies, introduced in April 2011 include requirements for gillnet operators to remove any biological materials from nets before they are set. This has been effective in reducing seabird interactions in other fisheries15.
  • The use of auto-longlines in the Southern and Eastern Scalefish and Shark Fishery (Gillnet Hook and Trap Sector) (Commonwealth) has raised concerns about the potential for interactions with seabirds, including albatrosses and shearwaters16. New measures have been implemented to assist industry to meet the Seabird Threat Abatement Plan17 and performance criteria18.
  • Demersal gillnets are known to interact with a number of threatened and protected species, including marine mammals and seabirds, in areas of Western Australia where they are used to catch School Shark. However, such interactions occur at a very low frequency and have been assessed as posing low–negligible risks to these populations19.
  • Recent analysis of potential changes in ecosystem structure of finfish in the South and West Coast Bioregions of Western Australia found no evidence of systematic changes in species diversity, richness or trophic index, indicating that the Western Australian fisheries are not having a material impact on the food chain or trophic structure in these regions20.
  • The demersal gillnets used to catch School Shark in Western Australia are deployed infrequently over a small proportion of the target fisheries’ operational area. Under normal circumstances, the physical impact of the gear on the benthic habitat is minimal19.
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Environmental effects on School Shark

  • Sea level rise and changes in sea temperature associated with climate change may negatively affect the School Shark biological stock because the habitats that School Shark use as nursery and feeding grounds are potentially prone to such effects20. Habitat modification, for example through installation of pipelines and outfalls, construction of piers, sewerage and industrial outlets, and land run-off may also affect nursery/pupping grounds21.
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References

  1. 1 Shark Resource Assessment Group 2011, 2011 stock assessment report for School Shark (Galeorhinus galeus), SharkRAG, Australian Fisheries Management Authority, Canberra.
  2. 2 Australian Fisheries Management Authority 2013, Species summaries for the Southern and Eastern Scalefish and Shark Fishery: for stock assessments completed in 2013 in preparation for the 2014–15 fishing season, AFMA, Canberra.
  3. 3 Thomson, R and Punt, A 2009, Stock assessment update for school shark Galeorhinus galeus based on data to 2008, reanalysis for SharkRAG meeting 17–18 November 2009, final draft, CSIRO, Hobart.
  4. 4 Thomson, R 2012, Projecting the School Shark model into the future: rebuilding timeframes and auto-longlining in South Australia, CSIRO, Hobart.
  5. 5 Shark Resource Assessment Group 2013, Shark Resource Assessment Group (SharkRAG) meeting outcomes: 8 March 2013, Australian Fisheries Management Authority, Canberra.
  6. 6 Marton, N and Savage, J 2015, Shark Gillnet and Shark Hook sectors, in H Patterson, L Georgeson, I Stobutzki and R Curtotti (eds), Fishery status reports 2015, Australian Bureau of Agricultural and Resource Economics and Sciences, Canberra, 244–267.
  7. 7 McAlister, JD, Barnett, A, Lyle, J and Semmens, J 2015, Examining the functional role of current area closures used for the conservation of an overexploited and highly mobile fishery species, ICES Journal of Marine Science, 72(8): 2234-2244
  8. 8  Last, PR and Stevens, JD 2009, Sharks and rays of Australia, CSIRO Publishing, Collingwood.
  9. 9 Moulton, PM, Walker, TI and Saddlier, SR 1992, Age and growth studies of gummy shark, Mustelus antarcticus (Günther), and school shark, Galeorhinus galeus (Linnaeus), from southern-Australian waters, Australian Journal of Marine and Freshwater Research, 43: 1241–1267.
  10. 10 Punt, AE and Walker, TI 1998, Stock assessment and risk analysis for the school shark (Galeorhinus galeus) off southern Australia, Marine and Freshwater Research, 49(7): 719–731.
  11. 11 Walker, TI 2005, Reproduction in fisheries science, in WC Hamlett (ed.), Reproductive biology and phylogeny of chondrichthyes: sharks, batoids and chimaeras, Science Publishers, Entfield, New Hampshire.
  12. 12 Ryan, KL, Wise, BS, Hall, NG, Pollock, KH, Sulin, EH and Gaughan, DJ 2013, An integrated system to survey boat-based recreational fishing in Western Australia 2011/12, Fisheries research report 249, Western Australian Department of Fisheries, Perth.
  13. 13 Giri, K and Hall, K 2015, South Australian Recreational Fishing Survey 2013/14, Fisheries Victoria Internal Report Series No. 62.
  14. 14 Australian Fisheries Management Authority 2011, Fisheries Management (Southern and Eastern Scalefish and Shark Fishery management plan 2003) Temporary Order 2011, AFMA, Canberra.
  15. 15 Australian Fisheries Management Authority 2014, Dolphin Strategy: minimising dolphin bycatch, September 2014, AFMA, Canberra.
  16. 16 Knuckey, I, Ciconte, A, Koopman, M, Hudson, R and Rogers, P 2014, Trials of longlines to target Gummy Shark in SESSF waters off South Australia, Fisheries Research and Development Corporation project 2011/068, produced by Fishwell consulting for the FRDC, Queenscliff.
  17. 17 Commonwealth of Australia 2014, Threat Abatement Plan 2014 for the incidental catch (or bycatch) of seabirds during oceanic longline fishing operations, Department of the Environment, Canberra.
  18. 18 Australian Fisheries Management Authority 2014, New measures to protect seabirds in SESSF auto-longline fisheries, AFMA, Canberra
  19. 19 McAuley, R, Braccini, M, Newman, SJ and O’Malley, J 2015, Demersal Gillnet and Longline Fisheries status report, in WJ Fletcher and K Santoro (eds), Status reports of the fisheries and aquatic resources of Western Australia 2014/15, Western Australian Department of Fisheries, Perth 261-272.
  20. 20 Hall, NG and Wise, BS 2010, Development of an ecosystem approach to the monitoring and management of Western Australian fisheries, Fisheries research report 215, Western Australian Department of Fisheries, Perth.
  21. 21 Australian Government Department of Sustainability, Environment, Water, Population and Communities 2011, Species group report card—sharks: supporting the draft marine bioregional plan for the South-west Marine Region, DSEWPaC, Canberra.

Archived reports

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