*

Mangrove Jack (2018)

Lutjanus argentimaculatus

  • Joanne Langstreth (Department of Agriculture and Fisheries, Queensland)
  • Thor Saunders (Department of Primary Industry and Resources, Northern Territory)
  • Fabian Trinnie (Department of Primary Industries and Regional Development, Western Australia)
  • Jeffrey Murphy (Department of Primary Industries, New South Wales)
  • Stephen Newman (Department of Primary Industries and Regional Development, Western Australia)
Toggle content

Summary

The long-lived Mangrove Jack is classified as sustainable stock in WA, recovering in the Gulf of Carpentaria and undefined in the NT and East Coast QLD. Stock status is negligible in NSW.

Toggle content

Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
Queensland East Coast Queensland CRFFF, ECIFFF Undefined Catch, effort
Queensland Gulf of Carpentaria GOCDFFTF, GOCIFFF Recovering Catch, effort, MSY
New South Wales New South Wales Negligible
Northern Territory Northern Territory CLF, DF, TRF, ACL Undefined Spawning stock biomass, fishing mortality
Western Australia Western Australia GDSMF, NDSMF, PFTIMF, PLF, PTMF Sustainable Catch
ACL
Aboriginal Coastal License (NT)
CLF
Coastal Line Fishery (NT)
CRFFF
Coral Reef Fin Fish Fishery (QLD)
DF
Demersal Fishery (NT)
ECIFFF
East Coast Inshore Fin Fish Fishery (QLD)
GDSMF
Gascoyne Demersal Scalefish Managed Fishery (WA)
GOCDFFTF
Gulf of Carpentaria Developmental Fin Fish Trawl Fishery (QLD)
GOCIFFF
Gulf of Carpentaria Inshore Fin Fish Fishery (QLD)
NDSMF
Northern Demersal Scalefish Managed Fishery (WA)
PFTIMF
Pilbara Fish Trawl (Interim) Managed Fishery (WA)
PLF
Pilbara Line Fishery (WA)
PTMF
Pilbara Trap Managed Fishery (WA)
TRF
Timor Reef Fishery (NT)
Toggle content

Stock Structure

Mangrove Jack are a long lived (> 50 years), late maturing species that can reach a length of over 1 m [Russell et al. 2003]. They are broadly distributed throughout the tropical and sub-tropical Indo-West Pacific [Allen 1985] and exhibit a biphasic life history pattern, where juveniles spend several years in freshwater and estuarine habitats before migrating offshore as they near sexual maturity, and have been reported to a depth of at least 175 m [Pradella et al. 2013]).

The distribution of this species within Australian waters extends from approximately Perth, Western Australia, around the north of the continent to Sydney, New South Wales [Pember et al. 2005, Russell et al. 2003]. Genetic analyses indicate that Mangrove Jack consist of a single biological stock across its Australian range [Russell et al. 2003]. This level of mixing is consistent with a life history that involves offshore spawning by adults. However, Mangrove Jack experience moderate to high harvest rates in some Australian fisheries (particularly those targeting adults of this long-lived species) which can cause localised depletion. While juvenile fish have been shown to migrate from freshwater and estuarine habitats to offshore reef environments, often with a movement component of up to 335 km [Russell et al. 2003], once these ontogenetic movements have occurred there have been no reports of adult fish undertaking extensive movements, although studies are limited. As such, limited evidence of adult movement in combination with evidence of different stock status in different regions indicates that Mangrove Jack likely comprise separate management units.

Here, assessment of stock status is presented at the management unit level―Queensland Gulf of Carpentaria and East Coast Queensland; and at the jurisdictional level―Western Australia, Northern Territory and New South Wales.

Toggle content

Stock Status

East Coast Queensland

There has been no stock assessment of this species in this management unit. There are commercial line and net fisheries in the area - the Coral Reef Finfish Fishery (CRFFF) and the East Coast Inshore Finfish Fishery (ECIFFF). Total catch from both in recent years was around 2 t [QDAF 2018]. There is a significant recreational fishery for this species but the Indigenous catch is considered to be low. Catch rates for the commercial net and line fishery are not considered to be reliable indicators of biomass because this species is not commercially targeted within this management unit.

Catch of Mangrove Jack in this management unit in the commercial line (1.5 t in 2016–17) and net (0.3 t in 2016–17) fisheries is stable and has been less than 5 t since 2009–10 [QDAF 2018]. The majority of catch is from the recreational fishery and is estimated at 49 t using data provided by the state wide recreational fishing survey 2013–14 [Webley et al. 2015]. Mangrove Jack is a popular recreational species in all habitats they occupy but considered to be difficult to target. The MLS is less than the size at maturity and preliminary fishery-dependent monitoring has documented a majority (> 90 per cent in 2017) of recreationally caught‑ fish are less than the size at maturity (L50 for females) [DAF unpublished data]. The impact of this on the stock is unknown. A portion of the biomass is not available to the fishery because of state marine parks and the Great Barrier Reef Marine Park (GBRMP) although the proportion protected has not been quantified. There is insufficient information available to confidently classify the status of this stock.

On the basis of the evidence provided above, the management unit is classified as an undefined stock.

Gulf of Carpentaria

A previous assessment of Mangrove Jack for the Queensland Gulf of Carpentaria conducted using data up to 2009 estimated an MSY  of 30 t for this management unit [O’Neill et al. 2011]. For eight years from 2003–04 to 2010–11 the Gulf of Carpentaria Developmental Fin Fish Fishery (GOCDFFTF) harvest exceeded the 30 t MSY, and between 2006–07 and 2008–09 was more than twice MSY [QDAF 2018]. Since 2012–13, effort has been absent or very low in the GOCDFFTF and harvest has been well below MSY each year. There was no commercial fishing in 2016–17. This reduction in effort for this management unit is due to a displacement of effort into Northern Territory by the small dual-endorsed fleet following implementation of management changes in both jurisdictions since 2011. The above evidence indicates that the biomass of this stock is likely to be depleted and that recruitment is likely to be impaired. However, for the period 2011–12 to 2016–17, the indicators of low to zero fishing effort and harvest well below MSY suggest a recovering stock.

There has been no commercial fishing in the GOCDFFTF since July 2016. The most recent catch in 2015–16 was only 13.5 t (56 fishing days) [QDAF 2018] compared to an MSY of 30 t. The new arrangements for the GOCDFFTF set catch triggers which limit effort and ensure that the MSY of 30 t will not be exceeded. Observer data (2004–06) showed that approximately a third of the Mangrove Jack retained in the GOCDFFTF are immature. Current bycatch reduction device (BRD) specifications for the GOCDFFTF are in place to ensure < 10 per cent of catch is < 350 mm (the minimum legal size [MLS] for Mangrove Jack), although the MLS is less than the size at maturity. Catch in the net fishery, Gulf of Carpentaria Inshore Fin Fish Fishery (GOCIFFF), is limited to the recreational in possession limit (5) and there has been no catch recorded since 2012–13. The most recent recreational harvest estimate (2013–14) was 4 500 fish (approximately 8 t) using data provided by the state wide recreational fishing survey 2013–14 [Webley et al. 2015] but this was based on a small sample size. This evidence indicates that the fishing pressure on the stock over the recent five year period (2012–13 to 2016–17) has been low with effort less than 65 commercial fishing days, allowing for recovery of this stock. The above evidence indicates that the current level of fishing mortality should allow the stock to recover from its recruitment impaired state.

On the basis of the evidence provided above, the management unit is classified as a recovering stock.

New South Wales

Stock status for the New South Wales stock is reported as negligible due to historically low catches in this jurisdiction, and because the stock has generally not been subject to targeted fishing. The New South Wales commercial catch in 2012–17 averaged less than 0.1 t per annum, and Mangrove Jack is not a major component of recreational landings. Fishing is unlikely to be having a negative impact on the stock.

Northern Territory

Mangrove Jack is a highly regarded fish in the Northern Territory but is one of the less common Lutjanids in this jurisdiction. Almost all Mangrove Jack caught by recreational fishers in the Northern Territory are harvested from estuarine and inshore habitats [West et al. 2012], whereas the majority of the commercial harvest (by the multi-species Timor Reef and Demersal Fisheries) occurs offshore.

The magnitude of the recreational harvest of this species is around 5 per cent of the commercial catch (derived from West et al. [2012] using a regional weight multiplier of 0.8 kg per fish, and contemporary commercial catch data). There are no estimates of the Indigenous harvest of Mangrove Jack in the Northern Territory. The lack of a long-term time series on recreational and Indigenous catches means that the assessment presented here is based on data from commercial logbooks.

The average annual commercial catch of Mangrove Jack in the Northern Territory for the decade spanning 2008–17 was 32 t. A preliminary assessment of this species using SimpleSA [NTG unpublished] indicates that the biomass of the stock is above the target biomass (at ≥ 50 per cent of 1983 biomass) but that fishing mortality rate from 2015–17 may have exceeded the target harvest rate (at 0.19 per annum). However, the level of uncertainty around these model outputs is too wide to make an informed judgement on the status of the stock. This uncertainty arises from the fact that Mangrove Jack is not actively targeted by the Timor Reef Fishery or the Demersal Fishery and because these fisheries have only scaled up in recent years. Hence, there is insufficient information available to confidently classify the status of this stock.

On the basis of the evidence provided above, Mangrove Jack in the Northern Territory is classified as an undefined stock.

Western Australia

Mangrove Jack are landed primarily on the north-west coast of Western Australia as a component of the multispecies Pilbara Demersal Scalefish Fisheries (PDSF: which includes the Pilbara Fish Trawl (Interim) Managed Fishery; the Pilbara Trap Managed Fishery; and the Pilbara Line Fishery) in the Pilbara management region of the North Coast Bioregion; and the Northern Demersal Scalefish Managed Fishery (NDSMF) in the Kimberley management region of the North Coast Bioregion of Western Australia [Newman et al. 2018a]. Mangrove Jack are assessed on the basis of the status of several indicator species (including, for example, Red Emperor and Goldband Snapper in the Kimberley region) that represent the entire inshore demersal suite of species occurring at depths of 30–250 m [Newman et al. 2018b]. The major performance measures for these indicator species are estimates of spawning stock levels. The target level of spawning biomass is 40 per cent of the unfished level. The limit level is 30 per cent of the estimate of initial spawning biomass [DPIRD 2017]. Indicator species assessments using an integrated age structured model determined that the spawning biomass levels of each of the indicator species in the PDSF were either greater than the target level or between the target and the threshold level in 2015 (the year the last integrated assessment was undertaken). The spawning biomass levels of the indicator species were either greater than the target level or between the target level and the threshold level in the NDSMF in 2014 [Newman et al. 2018a]. The above evidence indicates that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired.

The catch of Mangrove Jack in the PDSF has been low and stable for the past five years (2013–17), ranging from 8.8–12.3 tonnes (t), with a mean annual catch of 10.1 t. The catch of Mangrove Jack in the NDSMF has been low and stable for the past five years (2013–17), ranging from 0.6–1.7 t, with a mean annual catch of 1.3 t. The above evidence indicates that the current level of fishing mortality is unlikely to cause the stock to become recruitment impaired.

On the basis of the evidence provided above, Mangrove Jack in Western Australia is classified as a sustainable stock.

Toggle content

Biology

Mangrove Jack biology [Pember et al. 2005, Piddocke et al. 2015, Russell et al. 2003]

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Mangrove Jack 57 years, 1 019 mm FL Male: ≥ 7 years, 450 mm F L Female: ≥ 8 years, 510 mm FL
Toggle content

Distributions

Distribution of reported commercial catch of Mangrove Jack

Toggle content

Tables

Fishing methods
Western Australia Northern Territory Queensland New South Wales
Commercial
Hand Line, Hand Reel or Powered Reels
Otter Trawl
Unspecified
Fish Trap
Hook and Line
Beach Seine
Midwater Trawl
Net
Trawl
Charter
Hook and Line
Spearfishing
Indigenous
Hook and Line
Recreational
Hook and Line
Spearfishing
Management methods
Method Western Australia Northern Territory Queensland New South Wales
Charter
Bag limits
Gear restrictions
Limited entry
Passenger restrictions
Possession limit
Size limit
Spatial closures
Spatial zoning
Commercial
Bycatch limits
Gear restrictions
Limited entry
Quota
Size limit
Spatial closures
Spatial zoning
Temporal closures
Vessel restrictions
Recreational
Bag limits
Gear restrictions
Licence (Recreational Fishing from Boat License)
Possession limit
Size limit
Spatial closures
Vessel limits
Active vessels
Western Australia Northern Territory Queensland New South Wales
34 in Charter, 4 in GDSMF, 6 in NDSF, <3 in PFTIMF, 6 in PLF, <3 in PTMF, <3 in WL (NC || GC || WC) 12 in ACL, 14 in CLF, 8 in DF, 5 in TRF 46 in CRFFF, 17 in ECIFFF
ACL
Aboriginal Coastal License (NT)
Charter
Tour Operator (WA)
CLF
Coastal Line Fishery (NT)
CRFFF
Coral Reef Fin Fish Fishery (QLD)
DF
Demersal Fishery (NT)
ECIFFF
East Coast Inshore Fin Fish Fishery (QLD)
GDSMF
Gascoyne Demersal Scalefish Managed Fishery (WA)
NDSF
Northern Demersal Scalefish Fishery (WA)
PFTIMF
Pilbara Fish Trawl (Interim) Managed Fishery (WA)
PLF
Pilbara Line Fishery (WA)
PTMF
Pilbara Trap Managed Fishery (WA)
TRF
Timor Reef Fishery (NT)
WL (NC || GC || WC)
Open Access in the North Coast, Gascoyne Coast and West Coast Bioregions (WA)
Catch
Western Australia Northern Territory Queensland New South Wales
Commercial 10.76t in GDSMF, NDSMF, PFTIMF, PLF, PTMF 1.40kg in ACL, 56.00kg in CLF, 23.76t in DF, 28.85t in TRF 1.48t in CRFFF, 345.00kg in ECIFFF
Charter 1.72 t
Indigenous Unknown Unknown Unknown
Recreational 2.24 t ± 0.593 se 3 t (2009/10) 8.32 t (GOC), 48.58 t (EC) (2013–14)
ACL
Aboriginal Coastal License (NT)
CLF
Coastal Line Fishery (NT)
CRFFF
Coral Reef Fin Fish Fishery (QLD)
DF
Demersal Fishery (NT)
ECIFFF
East Coast Inshore Fin Fish Fishery (QLD)
GDSMF
Gascoyne Demersal Scalefish Managed Fishery (WA)
NDSMF
Northern Demersal Scalefish Managed Fishery (WA)
PFTIMF
Pilbara Fish Trawl (Interim) Managed Fishery (WA)
PLF
Pilbara Line Fishery (WA)
PTMF
Pilbara Trap Managed Fishery (WA)
TRF
Timor Reef Fishery (NT)

Western Australia Active Vessels data is unreportable as there were fewer than three vessels operating in Pilbara Fish Trawl Interim Managed Fishery and Pilbara Trap Managed Fishery.

Western Australia – Recreational (Catch) Boat-based recreational catch is from 1 September 2015–31 August 2016. These data are derived from those reported in Ryan et al. [2017]. Shore based catches of Mangrove Jack are not known.

Western Australia – Recreational (management methods) A Recreational Fishing from Boat License is required for the use of a powered boat to fish or to transport catch or fishing gear to or from a land-based fishing location.

Western Australia – Indigenous 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 recreational fishing licence, the non-commercial take by Indigenous fishers is covered by the same arrangements as that for recreational fishing.

Northern Territory Recreational Catch from West et al. [2012].

Queensland Commercial catch from 1 July 2016–30 June 2017.

Queensland – Recreational (catch) Survey of Queensland residents only from August 2013–October 2014 [Webley et al. 2015].

Queensland – Indigenous 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.

Toggle content

Catch Chart

Commercial catch of Mangrove Jack - note confidential catch not shown
Toggle content

References

  1. DPIRD 2017, North Coast demersal scalefish resource harvest strategy 2017–2021. Version 1.0. Fisheries Management Paper No. 285. Department of Primary Industries and Regional Development, Government of Western Australia, Perth, Australia. 35p.
  2. FAO species catalogue, volume 6, snappers of the world. FAO Fisheries Synopsis 125.
  3. Newman, SJ, Brown, JI, Fairclough, DV, Wise, BS, Bellchambers, LM, Molony, BW, Lenanton, RCJ, Jackson, G, Smith, KA, Gaughan, DJ, Fletcher, WJ, McAuley, RB and Wakefield, CB 2018, A risk assessment and prioritisation approach to the selection of indicator species for the assessment of multi-species, multi-gear, multi-sector fishery resources. Marine Policy, 88: 11–22.
  4. Newman, SJ, Wakefield, C, Skepper, C, Boddington, D, Jones, R and Smith, E 2018. North Coast Demersal Resource Status Report 2017. pp. 127–133. In: Gaughan, D.J. and Santoro, K. (eds.). Status Reports of the Fisheries and Aquatic Resources of Western Australia 2016/17: The State of the Fisheries. Department of Primary Industries and Regional Development, Western Australia, Perth, Australia. 237p.
  5. O’Neill, MF, Leigh, GM, Martin, JM, Newman, SJ, Chambers, M, Dichmont, CM and Buckworth, RC 2011, Sustaining productivity of tropical red snappers using new monitoring and reference points, The State of Queensland, Department of Employment, Economic Development and Innovation, Brisbane, Queensland.
  6. Pember MB, Newman SJ, Hesp SA, Young GC, Skepper CL, Hall NG and Potter IC 2005, Biological parameters for managing the fisheries for Blue and King Threadfins, Estuary Rockcod, Malabar Grouper and Mangrove Jack in north-western Australia. Final Report to the Fisheries Research and Development Corporation (FRDC) on Project No. 2002/003. Centre for Fish and Fisheries Research, Murdoch University, Murdoch, Western Australia, Australia. 172p.
  7. Piddocke, TP, Butler, GL, Butcher, PA, Stewart, J, Bucher, DJ and Christidis, L 2015, Age and growth of mangrove red Snapper Lutjanus argentimaculatus at its cool-water-range limits, Journal of Fish Biology, 86, 1587–1600.
  8. Pradella, N, Fowler, AM, Booth, DJ, Macreadie, PI 2013. Fish assemblages associated with oil industry structures on the continental shelf of north-western Australia. Journal of Fish Biology, 84(1): 247–255.
  9. Queensland Department of Agriculture and Fisheries 2018, Queensland Stock Status Assessment Workshop Proceedings 2018. Species Summaries. 19–20 June 2018, Brisbane.
  10. Russell, DJ, McDougall, AJ, Fletcher, AS, Ovenden, JR and Street, R 2003, Biology, management and genetic stocks structure of mangrove jack (Lutjanus argentimaculatus) in Australia. FRDC Project Number 1999/122, Department of Primary Industries, Queensland and the Fisheries Research Development Corporation, Brisbane.
  11. Ryan KL, Hall NG, Lai EK, Smallwood CB, Taylor SM, Wise BS 2017, Statewide survey of boat-based recreational fishing in Western Australia 2015/16. Fisheries research Report No. 287. Department of Primary Industries and Regional Development, Government of Western Australia, Perth. 
  12. Webley, J, McInnes, K, Teixeira, D, Lawson, A, Quinn, R 2015, Statewide Recreational Fishing Survey 2013–14, Queensland Department of Agriculture and Fisheries, Brisbane.
  13. West, LD, Lyle, JM, Matthews, SR and Stark, KE 2012, A survey of recreational fishing in the Northern Territory, 2009–10, Fishery report 109, Northern Territory Government Department of Resources, Darwin.