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Yellowtail Scad (2020)

Trachurus novaezelandiae

  • Matt Broadhurst (New South Wales Department of Primary Industries)
  • Rocio Noriega (Australian Bureau of Agricultural and Resource Economics and Sciences)
  • Jeff Norriss (Department of Primary Industries and Regional Development, Western Australia)
  • Anthony Roelofs (Department of Agriculture and Fisheries, Queensland)

Date Published: June 2021

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Summary

Yellowtail Scad has an Australian distribution from southern QLD to northern WA. The eastern stock of Yellowtail Scad is found in QLD, NSW and Commonwealth 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 Stock status Indicators
Queensland Eastern Australia Sustainable Historical catch and effort data, natural mortality, fishing mortality, fishing gear selectivity
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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 indicate 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 reported as “scad–unspecified”. A peak catch of 86 tonnes (t) and effort of 284 days were reported in 2002; of which 60 t was specifically reported as Yellowtail Scad [QFISH 2020]. Annual commercial catches have reduced to an average of 19 t since 2010. Effort has displayed the same trend, reducing from a peak of 502 days in 2006 to 242 days in 2019 [QFISH 2020]. 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 327 and 650 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].  The Commonwealth catch of Yellowtail Scad is relatively small. During 2018–19, there were 18 and 4 t reported in the Southern and Eastern Scalefish and Shark Fishery and Small Pelagic Fishery, respectively.  Operators in the Commonwealth-managed Eastern Tuna and Billfish Fishery take Yellowtail Scad as bait off New South Wales, but this is managed under permit, and with catches included in the NSW data below. The species is also caught in small quantities as a 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 ~16 to 30 t per year [Henry and Lyle 2003, West et al. 2015, Murphy et al. 2020]. The most recent estimate was ~166 000 fish or ~30 t during 2017–18 [Murphy et al. 2020]. This estimate was based on a survey of recreational fishing licence (RFL) households, which comprised at least one person with a long-term (one or three year) fishing licence, but also included other fishers within the household. A similar survey of RFL households was done in 2013–14 during which an estimated 61 000 Yellowtail Scad were recreationally harvested. 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 [Stewart et al. 1999, Stewart and Ferrell 2001, Neira 2009, Neira et al. 2015, Broadhurst et al. 2018, Broadhurst et al. 2020]. 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 FL at eight years, respectively [Stewart and Ferrell 2001]. Such growth variation is supported by a recent study on bioenergetics which showed an exponential increase in metabolic rate with temperature, implying twice the consumption requirements for northern vs southern fish [Dawson et al. 2020]. The estimated asymptotic fork 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 923 boat days in 2018–19, but an increase in nominal catch per unit effort from around 200 kg per boat day to between 300 and 400 kg per boat day in the most recent years [Broadhurst 2020]. As part of recent fisheries reforms, the stock is now subject to a total allowable catch (864 t for 2019–20). 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 are 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 [Stewart and Ferrell 2001, Broadhurst et al. 2018]

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
Queensland
Commercial
Line
Danish Seine
Net
Trawl
Recreational
Hook and Line
Indigenous
Various
Management methods
Method Queensland
Charter
Gear restrictions
Possession limit
Commercial
Gear restrictions
Limited entry
Spatial closures
Temporal closures
Total allowable catch
Vessel restrictions
Recreational
Gear restrictions
Possession limit
Catch
Queensland
Commercial 11.31t
Indigenous Unknown
Recreational Unknown

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) for more information see https://www.daf.qld.gov.au/business-priorities/fisheries/traditional-fishing

New South Wales – Recreational (catch) Murphy et al. [2020].

New South Wales – https://www.dpi.nsw.gov.au/fishing/aboriginal-fishing.

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Catch Chart

Commercial catch of Yellowtail Scad - note confidential catch not shown

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References

  1. Broadhurst, MK 2020, Stock assessment summary report 2019 – Yellowtail Scad (Trachurus novaezelandiae). NSW Department of Primary Industries. Fisheries NSW, Port Stephens Fisheries Institute. 7 pp
  2. 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
  3. Dawson, G, Suthers, IM, Brodie, S and Smith, JA 2020. The bioenergenetics of a coastal forage fish: Importance of empirical values for ecosystem models. Deep-Sea Res II. 175 (104700).
  4. 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.
  5. 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.
  6. Kennelly, SJ, Liggins, GW and Broadhurst, MK 1998. Retained and discarded by-catch from ocean prawn trawling in New South Wales, Australia. Fisheries Research, 36: 217–236.
  7. 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.
  8. Murphy, JJ, Ochwada-Doyle, FA, West, LD, Stark, KE and Hughes, JM 2020. The NSW Recreational Fisheries Monitoring Program - survey of recreational fishing, 2017/18. NSW DPI - Fisheries Final Report Series No. 158.
  9. 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
  10. 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.
  11. QFish, Department of Agriculture and Fisheries, www.qfish.gov.au
  12. 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.
  13. 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.
  14. 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.
  15. 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.

Downloadable reports

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