*

Mulloway is a widely distributed species in Australian waters. Stock status is sustainable in WA and SA, recovering in NSW and undefined in QLD.

Mulloway has a wide distribution in Australia, from the Gascoyne region on the west coast of Western Australia, around the southern coasts of the continent, and up to the Wide Bay–Burnett region on the east coast of Queensland [Kailola et al. 1993]. 

Biological stock structure for Mulloway in Australia is uncertain. It has been suggested that a single panmictic population occurs in Australia [Archangi 2008]. However, regional differences in genetics, and otolith morphology and chemistry suggest sub-structuring between populations in New South Wales, South Australia and Western Australia [Ferguson et al. 2011; Barnes et al. 2015; Hughes et al. 2022].

Here, assessment of stock status for Mulloway is presented at the jurisdictional level—Western Australia, Queensland, New South Wales and South Australia.

New South Wales

Commercial landings of Mulloway in New South Wales steadily declined from almost 400 tonnes (t) in the mid-1970s to a historic low of 37 t in 2008–09 and have been less than 100 t per year since the mid-1990s. In 2021–22, the total state-wide commercial catch was 79 t. Standardised catch per unit effort (CPUE; in days) for the two main fishing methods, estuary mesh netting and ocean line fishing both show substantial increases since 2009–10, particularly in the period from 2019–20 to 2021–22 [Hughes 2023]. Standardised CPUE for offshore handlining (reflecting abundance of mature fish), adjusted for increases in fishing power, increased by approximately 40% between 2009–10 and 2018–19, and has been stable at this level to 2021–22 [Hughes 2023].  

The most recent estimate of the recreational harvest of Mulloway in NSW was 6,431 (± 1,888 SE) individuals weighing an estimated 55 t in 2019–20 [Murphy et al. 2022]. In 2017–18, an estimated 13,641 (± 2,843 SE) individuals weighing an estimated 90 t were harvested [Murphy et al. 2020]. These estimates only encompassed harvest from NSW households within which a long-term NSW Recreational Fishing Licence holder resided (RFL household). Re-analysis of the previous survey [West et al. 2015] produced an estimate of 19,319 (± 6,554 SE) individuals weighing an estimated 103 t harvested by RFL households during 2013–14 [Murphy et al. 2020]. In 2000–01, estimated recreational harvest by all fishers in NSW waters was 59,029 (± 25,232 SE) individuals weighing an estimated 274 t [Henry and Lyle 2003]. While these survey results are not directly comparable due to different sampling frames, they likely represent a substantial decline in recreational harvest through time. Total historical harvest of Mulloway in NSW was also reconstructed by estimating recreational harvest prior to, and between, survey estimates [Hughes 2023].

The annual average lengths of Mulloway landed by the commercial fishery have declined since the mid-1990s but have been stable since the mid-2000s except for the effect of increasing the legal minimum length in 2013 [Silberschneider and Gray 2005; Silberschneider et al. 2009; Hughes 2023]. Up until 2016–17, the New South Wales commercial Mulloway fishery was based largely on juveniles, and the truncated length composition of fish in commercial landings since the early-2000s was indicative of a heavily fished stock (around 80% of catch was less than 700 mm, the approximate length at maturity for female Mulloway in New South Wales) [Silberschneider and Gray 2005; Silberschneider et al. 2009; Hughes 2023]. Only since 2015–16 has the average size of Mulloway in commercial landings indicated that the catch consists of adults (greater than 700 mm) and has been greater than 900 mm since 2017–18 [Hughes 2023].

Since the early 2000s, the spawning potential ratio (SPR) for Mulloway in New South Wales [Silberschneider et al. 2009; Hughes 2020] was consistently estimated to be below the threshold reference point of 20% of unfished with high probability indicating a risk of recruitment failure [Goodyear 1993; Mace and Sissenwine 1993]. Catch curve analysis over the same period consistently indicated that fishing mortality (F) was more than double natural mortality (M) [Hughes 2020].

In 2013, a recovery program for Mulloway was introduced in New South Wales designed to arrest the decline in commercial and recreational Mulloway fisheries. Numerous changes to recreational and commercial management have since been undertaken including an increase in legal minimum length from 450 to 700 mm, a staged reduction in daily recreational bag limits to one fish per day, a recreational boat limit of 2 fish per day, and the introduction of daily trip limits for all commercial fisheries. In addition, after several years of below average rainfall, environmental conditions for successful Mulloway recruitment [Stewart et al. 2020] likely occurred during the period between 2019–20 and 2021–22. 

Current median SPR is estimated to be 31% of unfished (range 15–39%) in 2021–22 [Hughes 2023] and infers increasing biomass since 2018–19 [Hughes 2020]. Outputs from integrated modelling approaches under development, including surplus production (CMSY++; [Froese et al 2021]) and within the Stock Synthesis framework [Methot and Wetzel 2013], using reconstructed catch histories (including both commercial and recreational components), standardised commercial CPUE time series and commercial length compositions, are also consistent with increasing biomass in recent years [Hughes 2023]. Model outputs estimate current biomass to be greater than the 20% limit reference point (B₂₀), but not with high certainty [Hughes 2023]. 

The above evidence indicates that the biomass of this stock may be depleted, and that recruitment may be impaired. However, for the period between 2019–20 and 2021–22 these indicators suggest a recovering stock.

Mortality estimates from integrated modelling approaches being developed indicate current F to be less than the median estimate of M [Hughes 2023]. Outputs from age-based catch curve analysis are also consistent with decreasing fishing pressure since 2018–19 [Hughes 2020].

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, Mulloway in New South Wales is classified as a recovering stock.

Mulloway biology [Farmer 2008; Silberschneider and Gray 2008; Ferguson et al. 2014]

Western Australia – Recreational (Catch totals). Shore based catches are unknown, thus landings are likely to be underestimated.

Western Australia – Indigenous (Management Methods). 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.

Queensland – Indigenous (Management Methods). For more information see: https://www.daf.qld.gov.au/business-priorities/fisheries/traditional-fishing

Queensland – Commercial (Catch). Queensland commercial and charter data have been sourced from the commercial fisheries logbook program. Further information available through the QueenslandFisheries Summary Report https://www.daf.qld.gov.au/business-priorities/fisheries/monitoring-research/data/queensland-fisheries-summary-report. 

Queensland – Recreational Fishing (Catch). Data with high uncertainty (Residual Error >50 %) has been excluded and listed as unknown. More information available at: https://www.daf.qld.gov.au/business-priorities/fisheries/monitoring-research/monitoring-reporting/statewide-recreational-fishing-surveys 

New South Wales – Commercial (Management Methods). Fishers using haul nets in the New South Wales commercial Ocean Hauling Fishery are permitted a bycatch allowance of 500 kg of Mulloway per day.

New South Wales – Recreational (Catch). Murphy et al. [2020], includes charter catch. 

New South Wales – Indigenous (Management Methods).  https://www.dpi.nsw.gov.au/fishing/aboriginal-fishing

Commercial catch of Mulloway - note confidential catch not shown

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