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Yellowtail Scad (2018)

Trachurus novaezelandiae

  • Matt Broadhurst (Department of Primary Industries, New South Wales)
  • Luke Albury (Department of Agriculture and Fisheries, Queensland)
  • Cher Harte (Australian Bureau of Agricultural and Resource Economics and Sciences)
  • Jeff Norriss (Department of Primary Industries and Regional Development, Western Australia)

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Summary

Yellowtail Scad have an Australian distribution from southern QLD to northern WA. The eastern stock of Yellowtail Scad is found in QLD, NSW and COMM waters and is classified as sustainable. Catches in the western stock are limited and the stock is undefined.

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Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
New South Wales Eastern Australia OHF, OTF, OTLF Sustainable Historical catch and effort data, natural mortality, fishing mortality, fishing gear selectivity
OHF
Ocean Hauling Fishery (NSW)
OTF
Ocean Trawl Fishery (NSW)
OTLF
Ocean Trap and Line Fishery (NSW)
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Stock Structure

Yellowtail Scad have an Australian distribution from southern Queensland to northern Western Australia [Stewart and Ferrell 2001], and also occur off New Zealand [Horn 1993]. The biological stock structure of Yellowtail Scad remains unknown; but in New South Wales there is evidence of spatial differences in growth rates which might be indicative of subpopulations [Stewart and Ferrell 2001]. Similar population variability has been observed for Yellowtail Scad in New Zealand [Horn 1993].

Here, assessment of stock status is presented at the biological stock level—Eastern Australia; and jurisdictional—Western Australia

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Stock Status

Eastern Australia

This cross-jurisdictional biological stock has components in southern Queensland and New South Wales. Each jurisdiction assesses the part of the stock that occurs in its waters. The status presented here for the entire biological stock has been established using evidence from all jurisdictions.

In Queensland, Yellowtail Scad are caught by net and line in the East Coast Inshore Fin Fish Fishery and the Stout Whiting Trawl Fishery. No assessment of Yellowtail Scad has been completed in Queensland with specific reporting of catch unreliable because the species is often recorded as part of a species complex “Scad–Unspecified”. A peak catch of 87 tonnes (t) and effort of 376 days were reported in 2002; of which 60 t was specifically reported as Yellowtail Scad [QDAF 2018]. Annual commercial catches have reduced to an average of 21 t since 2010. Effort has displayed the same trend, reducing from a peak of 608 days in 2006 to 279 days in 2017 [QDAF 2018]. The overall catch of Yellowtail Scad in Queensland contributes only a minor portion of the total Eastern Australia catch. Estimates of the recreational harvest of Yellowtail Scad in Queensland are unavailable, with only a few households reporting catch in a recent recreational fishing survey [Webley et al. 2015]. No recreational size limit exists for Yellowtail Scad, although a bag limit of 20 applies to all members of its family (Carangidae).

Most of the national landed catches of Yellowtail Scad are restricted to New South Wales, and typically have been between 300 and 600 t per year—up to 70 per cent of which is harvested by small boats (5–15 m long) deploying purse seines with variable mesh sizes (stretched mesh openings) between 10 and 150 mm and headline lengths from 275 to 1 000 m long [Stewart and Ferrell 2001]. There is a substantial Commonwealth component to the fishery, but these catches mostly are captured within New South Wales reporting. The species is also caught in small qualities as by-product by ocean prawn and fish trawlers [Kennelly et al. 1998]. The New South Wales recreational harvest of Yellowtail Scad (often used as live bait; Lowry et al. 2006) is substantially less at ~15 to 60 t per year [Henry and Lyle 2003, West et al. 2015]. There is no legal size for the species, although like for Queensland, recreational fishers in New South Wales are restricted to a generic daily personal bag limit of 20 fish.

Few Australian studies have assessed population parameters for Yellowtail Scad, and all work is limited to south eastern stocks [Broadhurst et al. 2018, Neira 2009, Neira et al. 2015, Stewart et al. 1999, Stewart and Ferrell 2001]. Spawning is assumed to occur along continental shelf waters during early spring, and potentially in response to discrete water masses with specific temperatures [Neira et al. 2015]. Size-at-age data derived from otoliths suggest that the species grows more slowly off southern than northern New South Wales, with mean sizes of 189 and 204 mm FL at two years and 231 and 272 mm at eight years, respectively [Stewart and Ferrell 2001]. The estimated asymptotic lengths are 238 and 308 mm , respectively [Stewart and Ferrell 2001].

Most of the purse-seine catch is based on fish aged two or three years [Stewart and Ferrell 2001, Broadhurst et al. 2018]. There has been a broad temporal reduction in effort from a peak of approximately 2 289 boat days in 1999–2000 to 642 boat days in 2015–16, but an increase in nominal catch per unit effort from around 200 kg per boat day to more than 400 kg per boat day in the most recent years. As part of fisheries reforms, in future the stock will be subject to total allowable catch. The above evidence indicates that the biomass of the stock is unlikely to be depleted and that recruitment is unlikely to be impaired.

Based on historical catches, along with size-at-age data, Broadhurst et al. [2018] modelled fishing mortality as low, while fleet selectivity was estimated to increase from nil at age zero to 100 per cent at age seven, and with a 50 per cent selection at age five. Natural mortality was estimated at 0.22 per year, comprising most of the total mortality [i.e. low fishing mortality; Broadhurst et al. 2018]. The above evidence indicates that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

The available data are few and limited to preliminary modelling that has precluded estimating biomass and recruitment. But, assuming accurate reporting of catches and effort, the Eastern Australian population of Yellowtail Scad appears to be stable. On the basis of the evidence provided above, the Eastern Australia biological stock is classified as a sustainable stock.

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Biology

Yellowtail Scad biology [Broadhurst et al. 2018, Stewart and Ferrell 2001]

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Yellowtail Scad 24 years, 330 mm FL 2–4 years, 200–220 mm FL 
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Distributions

Distribution of reported commercial catch of Yellowtail Scad
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Tables

Fishing methods
New South Wales
Commercial
Hook and Line
Purse Seine
Otter Trawl
Unspecified
Charter
Hook and Line
Various
Indigenous
Hook and Line
Recreational
Hook and Line
Various
Management methods
Method New South Wales
Charter
Fishing gear and method restrictions
Limited entry
Spatial closures
Commercial
Fishing gear and method restrictions
Limited entry
Spatial closures
Indigenous
Bag limits
Native Title
Section 37 (1d)(3)(9), Aboriginal cultural fishing authority
Recreational
Bag limits
Fishing gear and method restrictions
Spatial closures
Active vessels
New South Wales
13 in EGF, 9 in EPTF, 18 in OHF, 46 in OTF, 34 in OTLF
EGF
Estuary General Fishery (NSW)
EPTF
Estuary Prawn Trawl Fishery (NSW)
OHF
Ocean Hauling Fishery (NSW)
OTF
Ocean Trawl Fishery (NSW)
OTLF
Ocean Trap and Line Fishery (NSW)
Catch
New South Wales
Commercial 262.17t in OHF, 25.07t in OTF, 16.83t in OTLF
Charter Unknown
Indigenous Unknown
Recreational 15–60t
OHF
Ocean Hauling Fishery (NSW)
OTF
Ocean Trawl Fishery (NSW)
OTLF
Ocean Trap and Line Fishery (NSW)

Western Australia – Recreational (Management Methods) A ‘recreational-fishing-from-boat license’ is required when using a powered boat to fish, or transport catch or fishing gear to or from a land-based fishing location. Shore based catches are largely unknown

Queensland – Indigenous (Management Methods) Under the Fisheries Act 1994 (Qld), Indigenous fishers in Queensland are entitled to use prescribed traditional and Non-commercial fishing apparatus in waters open to fishing. Size and possession limits, and seasonal closures do not apply to Indigenous fishers. Further exemptions to fishery regulations may be applied for through permits.

New South Wales – Indigenous (Management Methods) (a) The Aboriginal Cultural Fishing Interim Access Arrangement allows an Indigenous 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; (b) 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 (1d)(3)(9), Aboriginal cultural fishing authority; and (c) In cases where the Native Title Act 1993 (Cth) applies fishing activity can be undertaken by the person holding native title in line with S.211 of that Act, which provides for fishing activities for the purpose of satisfying their personal, domestic or non-commercial communal needs. In managing the resource where native title has been formally recognised, the native title holders are engaged with to ensure their native title rights are respected and inform management of the State's fisheries resources.

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Catch Chart

Commercial catch of Yellowtail Scad - note confidential catch not shown
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References

  1. Broadhurst, MK, Kienzle, M and Stewart, J 2018, Natural mortality of Trachurus novaezelandiae and their size selection by purse seines off south-eastern Australia. Fisheries Management and Ecology 25: 332–338
  2. Henry, GW and Lyle, JM 2003, The national recreational and indigenous fishing survey. Australian Government Department of Agriculture, Fisheries and Forestry, Canberra, Australia. ISSN 1440–3544.
  3. Horn, PL 1993, Growth, age structure, and productivity of jack mackerels (Trachurus spp.) in New Zealand waters. New Zealand Journal of Marine and Freshwater Research, 27: 145–155.
  4. Kennelly, S.J., Liggins, G.W. and Broadhurst, M.K. 1998. Retained and discarded by-catch from ocean prawn trawling in New South Wales, Australia. Fisheries Research, 36: 217–236.
  5. Lowry, M, Steffe, A and Williams, D 2006, Relationships between bait collection, bait types and catch: A comparison of the NSW trailer-boat and gamefish-tournament fisheries. Fisheries Research, 78: 266–275.
  6. Neira, FJ, 2009, Provisional spawning biomass estimates of yellowtail scad (Trachurus novaezelandiae) off south-eastern Australia. New South Wales Department of Primary Industries Report, 32 pp
  7. Neira, FJ, Perry, RA, Burridge, CP, Lyle, JM and Keane, JP 2015, Molecular discrimination of shelf-spawned eggs of two co-occurring Trachurus spp. (Carangidae) in southeastern Australia: a key step to future egg-based biomass estimates. ICES Journal of Marine Science, 72: 614–624.
  8. Queensland Department of Agriculture and Fisheries 2018, Queensland Stock Status Assessment Workshop Proceedings 2018. Species Summaries. 19-20 June 2018, Brisbane.
  9. Stewart, J and Ferrell, DJ 2001, Age, growth and commercial landings of yellowtail scad (Trachurus novaezelandiae) and blue mackerel (Scomber australasicus) off the coast of New South Wales, Australia. New Zealand Journal of Marine and Freshwater Research, 35: 541–551.
  10. Stewart, J, Ferrell and Andrew, NL 1999, Validation of the formation and appearance of annual marks in the otoliths of yellowtail (Trachurus novaezelandiae) and blue mackerel (Scomber australasicus) in New South Wales. Marine and Freshwater Research, 50: 389–395.
  11. Webley, J, McInnes, K, Teixeira, D, Lawson, A and Quinn, R 2015, Statewide Recreational Fishing Survey 2013-14, Queensland Department of Agriculture and Fisheries, Brisbane.
  12. West, LD, Stark, KE, Murphy, JJ, Lyle, JM and Doyle, FA 2015, Survey of recreational fishing in New South Wales and the ACT, 2013/14. Fisheries Final Report Series No. 149. ISSN 2204-8669.