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Blacklip Abalone is harvested in NSW, SA, TAS and VIC, with twelve management zones. Stocks are sustainable in six zones, depleting in two zones, depleted in two zones, undefined in one zone and negligible in one zone.

There are substantial difficulties in applying classical stock assessment models to abalone resources, given the possibly large number of stocks in each fishery, and that stock structure in abalone depart substantially from dynamic pool assumptions required by integrated models. In some regions Haliotis rubra rubra also displays spatially variable growth rates and maturity curves. All jurisdictions therefore rely on indicators and empirical performance measures. Primarily these are commercial catch and catch per unit effort (CPUE; as kg of abalone harvested per hour). but they can also include commercial catch per area searched (CPUA), and metrics derived from fishery independent surveys, and commercial and fishery-independent size composition.   CPUE and similar indicators from individual fishing events are relevant locally but are not indicative of status broadly [Parma et al. 2003], and status of the many populations within a management unit cannot be assumed to be trending in the same direction. Thus, it is only the average CPUE across each spatial reporting unit that provides the broader perspective for fishery assessment. Fishery assessment is usually based on a combination of indicators, and some jurisdictions combine the indicators to give a combined score for stock status. The annual catch by Blacklip Abalone fisheries is generally close to the established total allowable commercial catches (TACCs), with little over-catch or under-catch of the TACC. 

South Australia Central Zone Fishery

Following the implementation of a total allowable commercial catch (TACC) in 1990, Blacklip Abalone catches and catch-per-unit-effort (CPUE) in the South Australia Central Zone Fishery (SACZF) were stable for more than a decade, at ~13 t meat weight per year and ~25 kg meat weight per hour, respectively. A long-term decline in CPUE began in the mid-2000s, and despite multiple reductions in TACC from 14.1 to 6.4 t, by 2016 CPUE had declined to 21 kg per hour. In 2017, CPUE declined further to 18 kg per hour, which was the lowest catch rate on record. These declines in catch rate, despite the reduced catches, indicate that recent recruitment levels have been substantially below those that have historically supported substantially larger catches. There had also been a spatial contraction of the fishery, principally into the south-western corner of Kangaroo Island, from a previously broader spatial distribution across the south coast of Kangaroo Island. At the start of the 2018 season, the fishery was closed, with the TACC set at zero, and was classified as ‘depleted’. The fishery was subsequently reopened for three fishing seasons from 2019 to 2021, where approx. 1 t of Blacklip Abalone was harvested per season, which was 90% below the average catches from 1979 to 2017. 

The most recent assessments for the fishery reported up to the conclusion of the 2021 calendar season [Burnell and Mayfield 2023; Burnell 2023]. The low level of blacklip catch combined with mixed-species fishing means that Blacklip Abalone CPUE estimates from 2019 onward differ substantially from, and cannot be directly compared with, CPUE estimates prior to 2018. Thus, from 2019, the limited data available were inadequate to measure the impact of the 2018 fishery closure.  

The above evidence indicates that Blacklip Abalone biomass has been reduced through catch and/or non-fishing effects, such that recruitment is impaired. Adequate management measures are currently in place, but have not yet resulted in measurable improvements. 

On the basis of the evidence provided above, the South Australia Central Zone Fishery management unit is classified as a depleted stock. 

South Australia Southern Zone Fishery

Catches of Blacklip Abalone in the South Australia Southern Zone Fishery (SASZF) were consistent around 140 t whole weight throughout the 1990s and 2000s, which followed the introduction of a total allowable commercial catch (TACC) in the early 1990s. Catches peaked at 151 t in the early 2010s, before a number of key indicators of stock performance began to decline across the fishery. There were also widespread abalone mortalities reported across the SASZF as a result of anomalously high water temperatures during the summer of 2012–13, which likely contributed to stock decline. Subsequently, catches declined to an average of 128 t over the last decade, associated with a combination under catch by industry and subsequent TACC reductions. Catches in the two most recent completed fishing seasons (i.e. 2020–21 and 2021–22) were consistent with the current TACC of 132 t whole weight [Burnell and Hogg 2023].

The most recent assessment report for the SASZF was completed in 2023 and reported on year-to-date data (October to April) for the 2022–23 season [Burnell and Hogg 2023]. The season in this fishery currently extends from 1 October to 30 September of the following year. Subsequent to this assessment, Abalone Viral Ganglioneuritis (AVG) has been detected, and mortalities observed, in the eastern part of this fishing zone. AVG has the potential to severely impact stocks (Mayfield et al. 2011). 

The primary measures for biomass and fishing mortality are catch-per-unit-effort (CPUE) and fishery independent survey (FIS) of legal-size abalone density [PIRSA 2021]. The CPUE for Blacklip Abalone in the SASZF increased consistently through time, almost doubling between the mid-1980s and 2010–11. Following record high CPUE in 2010–11 (~122 kg whole weight per hour), CPUE declined to ~94 kg per hour in 2014–15, before recovering steadily to reach 117 kg per hour in 2022–23, which is slightly below historical peaks. In 2022/23, estimates of CPUE for 7 out of 9 Spatial Assessment Units (SAUs) were substantially above target levels from the HS. There are four SAUs where FIS are undertaken in the SASZF. Estimates of legal-sized Blacklip Abalone density from the two SAUs with the largest catches (Middle Point and Number 2 Rocks) were at or above target levels. Whereas, in the two SAUs with smaller catches (Gerloffs Bay and Rivoli Bay), legal-sized Blacklip Abalone density was below target levels.

Application of the harvest strategy in 2022–23 resulted in a year-to-date zone score of 7.5 that, in combination with the zone trend score of 5.5 (reflecting an increasing trend), define the stock status for Blacklip Abalone in the SASZF in 2022-23 as ‘sustainable’. The above evidence indicates that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired.  Furthermore, 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, the South Australia Southern Zone Fishery management unit  is classified as a sustainable stock.

South Australia Western Zone Fishery

The total commercial catch for Blacklip Abalone has declined by 57 per cent from the stable catch over the decade ending 2012 (which averaged 101 t) to the 2023 total allowable commercial catch (TACC) (43.5 t) meat weight. This decline in catch was the combined effect of TACC reductions and the removal of one licence during the elimination of displaced catch/effort as part of the implementation of state marine parks. The total catch was further decreased by voluntary reductions in catch by the commercial sector from 2015 to 2019 [Stobart et al. 2019, 2020] and in 2021 [Stobart et al. 2021].

The most recent assessment for the SAWZF was completed in 2023 and reported up to the conclusion of the 2022/23 financial year season [Stobart 2023]. The primary performance indicators used to infer biomass and fishing mortality are commercial CPUE and FIS of legal-sized density by financial year [PIRSA 2021]. All reported metrics transitioned to financial year from 2021 onwards to align with the harvest strategy [Stobart et al. 2021]. The CPUE for Blacklip Abalone in the SAWZF increased from 24.4 kg per hour in 1980 to 30.7 kg per hour in 2006, the highest level on record. CPUE then decreased and, in 2019, was 20.0 kg per hour, the lowest value on record. With one exception, the long-term declining trend between 2005 and 2019 occurred across all the high and medium importance SAUs for the fishery [Stobart et al. 2020]. Estimates of legal-sized density from FIS also show general decreases following the late 2000s. 

CPUE has subsequently increased to 22.1 kg per hour in 2023 and there has been a stabilisation or increases of legal-sized density, generally matching the observed CPUE trend, except for two important fishing grounds, Drummond South and Avoid Bay that, in 2023, had the lowest legal density on record. The recent increase in CPUE and increases in legal density from three of the five FIS sites suggest that the reductions in catch may have arrested the observed declines in CPUE from 2005 to 2019. The trend reversal in both metrics from 2019 is evidence that, although biomass is low, fishing mortality is likely to be adequately controlled to avoid the stock becoming recruitment impaired. This was reflected in the status change from ‘depleting’ in 2018/19 to ‘sustainable’ in 2019/20. 

Application of the harvest strategy resulted in a zone score of 3.15 that, in combination with the zone trend score of 5.0 (reflecting a stable trend), define the stock status for Blacklip Abalone in the WZ in the 2022/23 financial year as ‘sustainable’. 

The above evidence indicates that the biomass of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired.  Furthermore, 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 the South Australia Western Zone Fishery management unit is classified as a  sustainable stock.

Blacklip Abalone biology [Shepherd 1973, Officer 1999, Tarbath et al. 2001, Tarbath and Officer 2003]

Distribution of reported commercial catch of Blacklip Abalone

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

Victoria – Indigenous (Management Methods) A person who identifies as Aboriginal or Torres Strait Islander is exempt from the need to obtain a Victorian recreational fishing licence, provided they comply with all other rules that apply to recreational fishers, including rules on equipment, catch limits, size limits and restricted areas. Traditional (non-commercial) fishing activities that are carried out by members of a traditional owner group entity under an agreement pursuant to Victoria’s Traditional Owner Settlement Act 2010 are also exempt from the need to hold a recreational fishing licence, subject to any conditions outlined in the agreement. Native title holders are also exempt from the need to obtain a recreational fishing licence under the provisions of the Commonwealth’s Native Title Act 1993.

Commercial catch of Blacklip Abalone - note confidential catch not shown

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