*

Blacklip Abalone

Haliotis rubra rubra

  • Craig Mundy (Institute for Marine and Antarctic Studies, University of Tasmania)
  • Ben Stobart (South Australian Research and Development Institute)
  • Corey Green (Department of Economic Development, Jobs, Transport and Resources, Victoria)
  • Greg Ferguson (South Australian Research and Development Institute)
  • Owen Burnell (South Australian Research and Development Institute)
  • Rowan Chick (Department of Primary Industries, New South Wales)
  • Stephen Mayfield (South Australian Research and Development Institute)
Toggle content

Stock Status Overview

Stock status determination
Jurisdiction Stock Fisheries Stock status Indicators
New South Wales New South Wales NSWAF Sustainable Catch, CPUE, mean weight
South Australia South Australian Central Zone Fishery SACZF Transitional-depleting Catch, CPUE 
South Australia South Australian Southern Zone Fishery SASZF Transitional-depleting Catch, CPUE 
South Australia South Australian Western Zone Fishery SAWZF Transitional-depleting Catch, CPUE 
Tasmania Tasmanian Bass Strait Zone Fishery TBSZF Sustainable Catch, CPUE 
Tasmania Tasmanian Central Western Zone Fishery TCWZF Transitional-depleting Catch, CPUE 
Tasmania Tasmanian Eastern Zone Fishery TEZF Sustainable Catch, CPUE 
Tasmania Tasmanian Northern Zone Fishery TNZF Transitional-depleting Catch, CPUE 
Tasmania Tasmanian Western Zone Fishery TWZF Transitional-depleting Catch, CPUE 
Victoria Victorian Central Zone Fishery VCZF Transitional-depleting Catch, CPUE, Fishery independent surveys
Victoria Victorian Eastern Zone Fishery VEZF Transitional-depleting Catch, CPUE, Fishery independent surveys
Victoria Victorian Western Zone Fishery VWZF Sustainable Catch, CPUE, Fishery independent surveys
Western Australia Western Australia Negligible
NSWAF
New South Wales Abalone Fishery (NSW)
SACZF
South Australian Central Zone Fishery (SA)
SASZF
South Australian Southern Zone Fishery (SA)
SAWZF
South Australian Western Zone Fishery (SA)
TBSZF
Tasmanian Bass Strait Zone Fishery (TAS)
TCWZF
Tasmanian Central Western Zone Fishery (TAS)
TEZF
Tasmanian Eastern Zone Fishery (TAS)
TNZF
Tasmanian Northern Zone Fishery (TAS)
TWZF
Tasmanian Western Zone Fishery (TAS)
VCZF
Victorian Central Zone Fishery (VIC)
VEZF
Victorian Eastern Zone Fishery (VIC)
VWZF
Victorian Western Zone Fishery (VIC)
Toggle content

Stock Structure

Empirical field studies1 and molecular techniques2,3 strongly suggest Blacklip Abalone (Haliotis rubra rubra) fisheries comprise a large number of small, ecologically independent populations. Each biological stock may extend over only a few hundred metres, with each Blacklip Abalone fishery likely consisting of an indeterminate number of small biological stocks (populations), which may number in the thousands for a single fishery management unit. Given the large number of biological stocks, it is not practical to assess each stock separately.

Here, assessment of stock status is presented at the jurisdictional level—Western Australia; and at the management unit level (for each spatial quota management area)—New South Wales Abalone Fishery, Victorian Central Zone Fishery, Victorian Eastern Zone Fishery, Victorian Western Zone Fishery, Tasmanian Bass Strait Zone Fishery, Tasmanian Central Western Zone Fishery, Tasmanian Eastern Zone Fishery, Tasmanian Northern Zone Fishery, Tasmanian Western Zone Fishery, South Australian Central Zone Fishery, South Australian Southern Zone Fishery and South Australian Western Zone Fishery.

Toggle content

Stock Status

All states rely on empirical performance measures, specifically catch, catch per unit effort (CPUE; as kg of abalone harvested per hour), and commercial catch size structure. The annual catch in Blacklip Abalone fisheries is generally equivalent to the total allowable commercial catch (TACC) with negligible over-catch or under-catch of the TACC. In some jurisdictions, additional fishery-independent data (density, size structure) are available from underwater research surveys.

 

As the spatial extent of individual fishing events (dives4) or fishery-independent survey sites is approximately the same size as a functionally independent abalone population, and that habitat structure often changes on a similar spatial scale, the combination of these features make assessment of abalone stock status more complicated than most fisheries. Common values for catchability, recruitment, growth and natural mortality cannot be assumed for a management unit, and status of the many populations in a management unit should not be assumed to be trending in the same direction. Thus attempts to model a management unit as a single stock, or to use other methods to arrive at ‘global’ estimates of biomass should be approached cautiously. Catch rates are an index of local abundance only, that is, localised to each fishing event or to each survey site and local catch and catch rates do not inform status of more distant fishing grounds within the same management unit. Fishing effort in abalone fisheries is also subject to a range of influences (wave height and power, wind, currents, water clarity) creating short-term biases or variability in CPUE that are not related to resource abundance.

 

The New South Wales Abalone Fishery is managed as a single management unit with a single TACC, set by an independent Total Allowable Catch Committee. Annual assessments have relied heavily on fishery-dependent data from logbooks, including catch, catch rate (kg per hour) and mean weight, summarised at a range of spatial scales. Most recent assessments have also utilised estimates of legal size biomass density at fine spatial scales, derived from GPS data-loggers and data from logbooks.

The Victorian abalone fisheries are assessed using a weight-of-evidence approach, incorporating fishery-dependent commercial catch, effort, CPUE and length frequency data (from 1992 onwards), and fishery-independent fixed site surveys of abalone abundance and size structure. Trends in abalone abundance in two size classes are considered, using the legal minimum length (LML) established in 1992 (110 mm/120 mm Central Zone; 120 mm Eastern Zone, Western Zone)–density of abalone recruits (greater than the LML) and density of pre-recruits in a size band 40 mm below the LML. While fishery-independent survey data are available from 1992 onwards, data are only considered here from 2003–15, due to an increase in number of survey sites and other methodology changes introduced at this time, thus making it difficult to compare with data prior to 2003. The value of this fishery-independent survey is disputed by some sectors, although a recent review showed it to be broadly useful for determining relative stock status5. Commercial CPUE data and diver observations are evaluated at the scale of the management zones and at finer scales within each zone. Commercial CPUE data are used in both raw and standardised form6. Importantly, interpretation of these data is conducted within the context of historical changes in the management, fishing methods and other non-fishing impacts on the populations with each zone.

 

The Tasmanian abalone fishery has been quota managed with an annual TACC since 1985, and up to 1999 there was a single Tasmanian TACC that did not differentiate between species or area. In response to increased regional fishing pressure through the late-1990s, separate TACCs for Greenlip Abalone and Blacklip Abalone were implemented in 2000, and the Blacklip Abalone fishery was divided into two zones (Eastern Blacklip, Western Blacklip). Also in 2000, finer-scale reporting of fishing within sub-blocks was introduced. Further spatial partitioning of the Tasmanian Blacklip Abalone fishery occurred in 2001, with the northern areas of the Eastern and Western Zone moving into a Northern Blacklip Zone. In 2003, the Northern Zone was split into two zones with different size limits (Northern Blacklip and Bass Strait Blacklip). In 2009, the Western Blacklip Zone was split into Western Blacklip and Central West Blacklip zones, and the boundary between the Western and Central West Blacklip zones was moved northwards in 2013.

Around 65 per cent of the total Tasmanian wild abalone harvest is exported live to Asia, with the remaining fraction processed in canned or frozen form. The fishery lands abalone live, and all catch rates are in whole live weight.

An empirical harvest strategy (HS) was developed for the Tasmanian abalone fisheries in 2014–157,8 and tested by Management Strategy Evaluation (MSE)9,10. The HS was trialled in the Tasmanian abalone fishery assessment for the first time in 2015, jointly with the previous ad hoc approach4. The HS assesses the fishery performance against target reference points for three performance measures (PM) derived from standardised CPUE (SCPUE) data: current CPUE relative to an agreed target (55th percentile of the annual standardised mean CPUE within the reference period); the 4 year gradient of CPUE (target gradient is zero); and the per cent change in SCPUE in the past year (target change is zero). The reference period for the 2015 assessment spans fishery data between 1992 and 2015. A scoring function is applied to the three PMs resulting in a score between zero and 10, where five is the target PM value and zero and 10 are the zone-wide lowest and highest values for that PM within the reference period. Weightings are applied to the three PMs 05:0.25:02.5 to provide a combined final score used in the control rule. The HS is applied individually to each statistical reporting block, and a zone score is obtained from the mean block score weighted by block catch.

The zone target CPUE PM score is used as a proxy for biomass and the zone gradient CPUE PM score is used as a proxy for fishing mortality. A target CPUE score of one is the limit reference point (LRP) defining the boundary between recruitment overfished and transitional–depleting for all Tasmanian management units. This LRP is typically five per cent above the lowest SCPUE observed within the zone during the reference period. A negative zone gradient score gives evidence that fishing mortality is increasing and the magnitude of the gradient provides some information on the magnitude of fishing mortality. In order to emulate a normal phase plot, five is subtracted from the 4 year gradient PM score to provide a range of negative five–positive five, where the target reference point is zero, and defines the boundary between sustainable and transitional–depleting classifications, but also between transitional–recovering and recruitment overfished. The combination of a negative CPUE gradient and near-record low CPUE score represents a cautious proxy for the true recruitment overfished reference point. No reporting blocks have collapsed within the reference period, providing a degree of certainty that the LRP will prevent stock collapse, which is supported by MSE testing of the HS.

The Tasmanian Abalone Fishery Management Plan policy document requires size limits be established that allow two breeding seasons post-reproductive maturity. Research programs11 to obtain empirical data representing the geographic variability in growth rates and size at reproductive maturity have been underway since 1985, resulting in a range of LML regulations within the Tasmanian Blacklip Abalone fisheries ranging from 110–145 mm.

 

In South Australia, the harvest strategy in the Management Plan for the commercial abalone fishery12 produces a catch weighted determination of stock status for the fishing zone. However, the harvest strategy does not identify performance indicators or reference points for classifying the fishery under the Status of Australian Fish Stocks framework. The reference points described in the harvest strategy were developed as a scoring mechanism for the performance indicators, not as a stock classification tool. While there is some variability among management units, the harvest strategy was developed at a time when the fishery was considered to be stable and was partly designed to maintain that stability. Reference points are used to score performance indicators, with negative scores for low current values and positive scores for high current values, when assessed against a fixed 20-year reference period (1990–2009). The intent was to prevent the fishery declining to abundance levels in the 1990s, that preceded the large increase in abundance (presumably through strong recruitment) in the 2000s13,14, whilst simultaneously allowing increased abundance to translate to elevated TACCs. The harvest strategy appears to result in more optimistic assessments of stock status than those from weight-of-evidence methods applied elsewhere13,14. Concerns with the harvest strategy have resulted in a review that is currently underway. Consequently, in this assessment, nominal commercial catch rates (CPUE based on: meat weight in the Central and Western Zone management units; and shell [whole] weight in the Southern Zone management unit) are used as the primary index of relative Blacklip Abalone abundance. CPUE can provide a more optimistic index of relative abundance than measures from fishery-independent surveys, because catch rates in dive fisheries have been shown to be hyperstable13–18. Decreases in CPUE in abalone fisheries are considered to be a reliable indicator of declines in abalone abundance, but nominal CPUE can underestimate the actual magnitude of the reduction in harvestable biomass13–18.

Western Australia

Stock status for the Western Australia is reported as negligible due to low catches by this jurisdiction.This stock is generally not targeted by commercial fishers and not recorded by charter operators. Very small catches by recreational fishers are recorded in recreational surveys.

New South Wales

Blacklip Abalone stocks in New South Wales have substantially recovered, or are recovering, from what are now understood to be historically persistent levels of overfishing and over-depletion19,20. Recent changes in the status of the stock, together with substantial contrast in historical and recent fishery-dependent measures (notably, catch and catch rate) provide a basis to infer historical status and reference levels of catch rate, assuming they are comparable and provide a relative measure of stock abundance through time.

The historical status of stocks, inferred largely from changes in the level of catch rate though time and the overfished status of the stock in the mid-2000s, strongly indicates that stocks were subject to recruitment overfishing and were overfished in the mid-1980s (catch rate less than 20 kg per hour) and that overfishing continued throughout the 1990s to the mid-2000s (catch rate less than 20 kg per hour, with intermittent peaks to less than 25 kg per hour). This period of declining and historically low catch rate occurred during a period of relatively stable catches through the 1990s and a reduction in TACCs during the early-2000s from 305–130 tonnes (t)

Following further reductions in TACCs, to 75 t in 2010, there has been a strong and steady recovery in catch rate and mean weight of abalone, particularly from southern areas of New South Wales, which provide most of the catch, to levels not previously recorded in the fishery. In 2010, the catch rate exceeded 30 kg per hour for the first time since the early-1980s and has increased annually, to about 50 kg per hour in 2015. In addition, recent measures of legal size biomass density (kg per hectare) derived from GPS-logger and logbook data, indicate that there has been a two-fold increase in biomass since 200919. These GPS-logger estimates have a greater precision than catch rates from logbook data alone, which may overestimate increases in abundance. In response to these indicators of increasing biomass19, the TACC has been cautiously increased since 2011, and in 2015 was 130 t. Additional protection for the fishery has also been achieved through several increases in the LML from 100 mm, established in 1972, through four increases to 117 mm in 2008. In the southern areas of the state, the LML for the commercial fishery was increased further to 120 mm in 2010 and then 123 mm in 2013. On this basis, a catch rate of 30 kg per hour seems appropriate as a limit reference point below which the stock would be classified as recruitment overfished.

Stock recovery has not been uniform throughout the state, with evidence indicating the greatest levels of rebuilding in the south. Northern stocks were subject to high exploitation rates through the mid- to late-1980s and early-1990s and were further depleted by mortality associated with infection by the parasite Perkinsus sp.19,20 during the 1990s and into the early-2000s. Stock within this northern area has not demonstrated similarly strong, consistent improvements in fishery-dependent data, compared to those observed in the south. Relatively low, sporadic catches, together with modest and variable increases in CPUE and mean weight, suggest that recovery is occurring, but the status of these northern stocks is less certain.

The evidence presented above indicates that the stock within the New South Wales management unit was overfished through the mid-1980s and into the early-2000s. Since the early-2000s, management measures have supported ongoing recovery, as indicated by changes in catch rate and mean weight of abalone in the commercial catch since the mid-2000s. Recent performance measures indicate that stocks are continuing to recover, although at a slower rate19 and current management measures provide greater protection to the fishable biomass, with LMLs being more precautionary than at any other time in the history of the fishery. A fishery harvest strategy is under development to provide greater certainty in the response of management to future changes in the performance of the fishery.

The above evidence indicates that stocks in the New South Wales Abalone Fishery are unlikely to be recruitment overfished and that the current level of fishing mortality is unlikely to cause these stocks to become recruitment overfished.

On the basis of the evidence provided above, the New South Wales Abalone Fishery management unit is classified as a sustainable stock.

Victorian Central Zone Fishery

Consistent among all Victorian management units, unstandardised commercial CPUE increased from about 65 kg per hour in the mid- to late-1990s to about 100 kg per hour in the early-2000s, with the increase thought to be influenced by changes in fishing practices that improved fishing efficiency21. CPUE peaked in the early-2000s at close to 100 kg per hour, but has shown a declining trend since, and in 2014–15 was at approximately 75 kg per hour and 75 per cent of the 2001 peak. This decline is of concern, however, the management unit is not considered to be recruitment overfished because the current CPUE is above 1992–93 levels, from which recovery was seen in the past. While some of the variation in CPUE since 2001 may be attributed to changes in LML and industry imposed size limits greater than the LML for individual reefs, declining CPUE trends have been observed since 2001 across most sub-zonal management units. The abalone viral ganglioneuritis (AVG) outbreak in the far west of the zone probably contributed to declining catches and catch rates, but the impacts were considered minor.

The TACC was reduced substantially from 620 t in 2006–07 to 285 t in 2010–11, and has since ranged from 279–307.7 t. TACCs have closely reflected the catch.

Trends in fishery-independent survey data were consistent with a decline in CPUE, showing a major decline in 2003–09 in the pre-recruit and recruit abundance indices (number/transect) of approximately 60 per cent and 55 per cent, respectively. Since 2009, the survey index of recruit abundance has been stable, while the pre-recruit index has continued to decline at a lower rate. In 2015, the pre-recruit abundance index was at approximately 25 per cent of that measured in 2003 and 2004, although it is not yet clear whether this represents an overfished stock.

While fishing pressure was reduced through progressive decreases in the TACC of about 50 per cent from 2003–04 to 2010–11, more recently (with the exception of 2013–14), TACCs have been higher than in 2010–11 by between 13 and 47 t. This is despite the stable, but relatively low, levels of commercial CPUE and fishery-independent survey indices. The above weight of evidence indicates that the current level of fishing pressure is likely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, the Victorian Central Zone Fishery management unit is classified as a transitional–depleting stock.

Victorian Eastern Zone Fishery

The Eastern Zone management unit was not affected by AVG, but has seen impacts from environmental and ecosystem changes such as range expansion by the Long Spined Sea Urchin (Centrostephanus rodgersii)22. These urchins denude reefs of macro-algae, turning the reefs into ‘barrens’ that are unsuitable for abalone. Significant areas of reef in the Eastern Zone have been rendered unsuitable for abalone due to urchin expansion over the past 20 years22. This has led to increased fishing effort on urchin-free reef areas, with increased risk of localised depletion. Improvements in fishing methods have also occurred in this zone, and are thought to have caused fishing efficiency-related increases in CPUE from the mid-1990s–early-2000s.

Commercial CPUE (standardised) increased from about 70 kg per hour in 1992 to peak levels of about 120 kg per hour in 2011–1223. However, from 2011–15 CPUE declined by 20 per cent. Similarly, most sub-zonal management units have shown declines in CPUE in recent years. These declines are of concern, however, the management unit is not currently considered to be overfished because the CPUE suggests that biomass is now close to 2004-05 levels (100 kg per hour), from which recovery was seen in the past. This catch rate is also considered to be above levels observed in other abalone fisheries where stocks are not considered overfished.

The fishery-independent survey indices show relatively stable pre-recruit abundance from 2003–09, after which pre-recruit abundance declined by approximately 40 per cent, until 2014. The last few years of the pre-recruit survey index have been stable at 2014 levels. From 2003–08, the survey index of recruit abundance declined by approximately 55 per cent, and has also remained steady over the past 4 years.

In response to declining CPUE and survey indices, there has been an incremental reduction of TACCs since 2008–09, from 490 t in that year to 417 t in 2014–15. While there are signs of recent stability in the pre-recruit and recruit survey indices, it is too soon to tell whether this stability will continue, or if the current management arrangements and quota reductions are sufficient for preventing further decline and allowing the stock to rebuild. The recent declines in CPUE across much of the zone are concerning, as is the ongoing vulnerability of the zone to further habitat loss from urchins. The evidence indicates that biomass is declining in the zone, but this has been from historically high levels and it is not yet considered to be an overfished stock.

The above weight of evidence indicates that the current level of fishing pressure, combined with possible further impacts of increased habitat loss from urchins, is likely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, the Victorian Eastern Zone Fishery management unit is classified as a transitional–depleting stock.

Victorian Western Zone Fishery

The western zone management unit has undergone significant changes over its recent history. Most notable was the impact of the outbreak AVG in 2006. Mortalities due to this disease severely reduced the biomass and resulted in a major reduction in TACC for this zone from 280 t in 2001–02 to 20 t in 2008–09. While some fishing occurred on uninfected reefs for a period immediately after the disease was first recognised, by 2008 most areas in the Western Zone had been impacted and/or were closed to fishing. These events complicate the comparison of recent and historical fishery-dependent and independent data.

Progression of the disease through the fishery had abated by 2009, enabling fishers and researchers to conduct a structured fishing program24 to gather information and assess capacity of remaining stocks to support a viable commercial fishery. Under this program, divers were assigned fishing areas, some of which were seldom fished in the past. In some cases, harvest on disease free reefs was initially set at zero to insure the maintenance of some healthy animals. From 2011 onwards, most reef areas were again open to fishing and ‘normal’ fishing practices resumed under a much reduced quota of 53 t and a higher LML (130 mm) than pre-AVG. Only trends in commercial CPUE from 2011 onwards are used in this assessment, due to the large changes that occurred prior to this. While there has been no formalised rebuilding strategy, fishing has been kept low by a precautionary TACC level set at approximately 50 t (or 10 per cent of estimated available biomass)25–27. Estimating available biomass involves the use of survey data to determine abalone density, converting numbers to biomass using length to weight relationships, and scaling the biomass estimates by the area of the fishing grounds27.

Commercial CPUE for the management unit as a whole increased from 1992–2001, a period influenced by changes in fishing practice and the adoption of improved technology–both of which led to increased efficiency of the fleet. CPUE from 2001–05 declined slightly, until the 2006 AVG outbreak, resulting in substantial declines in catch and catch rate. After ‘normal’ fishing practices were resumed in 2011, CPUE increased until 2013, possibly due to fishers being able to target the more productive reefs again after the structured fishing ended. Since 2013, CPUE has stabilised at approximately 70 kg per hour across the zone compared to approximately 90 kg per hour during the 1990s and early-2000s, prior to AVG impacts. The current catch rate is evidence that the biomass is at a level comparable with stocks in other management units (for example, the Victorian Central Zone) which are not considered to be recruitment overfished. Since 2011, the TACCs have been reflected by the catch.

The fishery-independent survey data from 2003 onwards clearly show the impact of the AVG mortalities, with declines in the survey abundance indices (number/transect) for both pre-recruits and recruits of approximately 80 per cent and 40 per cent respectively from 2003–09. From 2009 onwards, both survey indices have been stable through to 2015, although the pre-recruit survey index has remained at about 30 per cent of that recorded prior to disease in 2003, while the recruit survey index is at approximately 70 per cent of that measured in 2003. The above evidence indicates that the biomass of the stock is unlikely to be recruitment overfished, as long as the AVG did not disrupt the fundamental breeding and juvenile recruitment processes.

The fishery-dependent and independent information indicate that the management unit has been stable since 2011, but at a much lower biomass than pre-AVG. The recent stability of the commercial CPUE under the higher LML, combined with stability of the fishery-independent pre-recruit and recruit survey indices, suggest that the current management arrangements restricting fishing pressure are not causing further decline. The management unit is not, however, substantially rebuilding. The above evidence indicates that the current level of fishing pressure is unlikely to cause the stock to become recruitment overfished.

On the basis of the evidence provided above, the Victorian Western Zone Fishery management unit is classified as a sustainable stock.

Tasmanian Bass Strait Zone Fishery

Two different LMLs are in place (110 mm and 114 mm) in this zone, reflecting the variation in growth rates within this zone. Since the creation of this zone in 2003, catch and SCPUE have been relatively stable. The Bass Strait Zone was closed in 2007, due to concerns around the possible risk of transferring AVG from Victoria to Tasmania, and re-opened in 2008. In 2015, the TACC for the Bass Strait Zone remains at 70 t, and the zone-wide catch weighted block mean SCPUEcw was 87 kg per hour, compared with 79.1 kg per hour when the zone was established in 20034. The zone-wide proxy for biomass is 6.5 and well above the LRP and the zone-wide proxy for fishing mortality is 0.4 and just above the TRP for sustainability4.

The above evidence indicates that stocks in the Tasmanian Bass Strait Zone are unlikely to be recruitment overfished and that the current level of fishing pressure is unlikely to cause these stocks to become recruitment overfished.

On the basis of the evidence provided above, the Tasmanian Bass Strait Zone Fishery management unit is classified as a sustainable stock.

Tasmanian Central Western Zone Fishery

The Tasmanian Central Western Zone Fishery management unit has a LML of 132 mm. This part of the west coast was underexploited in the early- to mid-2000s4 in preference to southern areas, where higher beach prices were achievable for the live market and spatial management measures were used to shift effort into this region in 2009. SCPUE has oscillated over the past 15 years, but has declined over the past 5 years, suggesting the biomass has been reduced. During 2012, 127 t was harvested from this area and associated with the zone boundary change, the TACC in this management unit was reduced by 20 per cent in 2013 to 105.1 t28, by 25 per cent in 2014 to 73.5 t, and a further 28 per cent in 2015 to 52.5 t. The intention is to continue reducing the TACC until there is unambiguous evidence of stock rebuilding4. The mean SCPUE in 2015 was 62.8 kg per hour compared with an SCPUE of 136.5 kg per hour when this zone was created in 2009. The rate of decline in SCPUE since 2012 has been sharp despite several TACC reductions. The zone-wide proxy for biomass is 1.1, marginally above the LRP, while the proxy for fishing mortality is -3.7, which is below the TRP for sustainability4.

The above evidence indicates that the stocks in the Central Western Zone are not likely to be recruitment overfished, but that the current level of fishing pressure is likely to cause the stocks to become recruitment overfished.

On the basis of the evidence provided above, the Tasmanian Central Western Zone Fishery management unit is classified as a transitional–depleting stock.

Tasmanian Eastern Zone Fishery

The majority of the Tasmanian Eastern Zone Fishery management unit has a LML of 138 mm, while the LML for a small area around Freycinet is set at 145 mm as part of a rebuilding program4. Relative stock biomass in this fishery (estimated using SCPUE as a proxy) has oscillated substantially since 1992, with evidence of an approximate 8-year cycle4. Based on declining mean SCPUEcw between 2000 (76 kg per hour) and 2003 (53.8 kg per hour), the TACC was reduced from 1190–857 t in 2002 and to 770 t in 200429. Subsequent increases in SCPUE and increasing median length of the commercial catch led to increases in the TACC by five per cent in 2008, 2009 and 201030, resulting in a TACC of 896 t by 2010. Between 2007 and 2009, the mean SCPUEcw was stable at around 90 kg per hour, but reports from divers suggested the resource was declining in late-2009. Rapid declines in SCPUE in late-2010 resulted in a reduced TACC of 721 t for 2011. Mortality (per cent unknown) of abalone in the wild across a large proportion of the Eastern Zone was observed in March 2010, coincident with a marine heat wave. Further rapid decline in 2011 resulted in an additional TACC reduction to 549.5 t for 2012. In 2013, minor reductions in the TACC to 528.5 t were made to address local concerns in one sub-region and held for 2014 and 20154. In 2015, the mean SCPUEcw was 59 kg per hour and has been stable at this level for 4 years. There was evidence of stock rebuilding in several key areas of the Tasmanian Eastern Zone in 2014 and 2015, primarily in the south, with some areas in the north of the zone declining. There remains an intent to further reduce the TACC to trigger faster rebuilding of biomass and to ensure the fishery remains resilient to further environmental change. Overall, the zone-wide proxy for biomass is 3.6 and above the LRP of 1 and the zone-wide proxy for fishing mortality is 0.1 and above the TRP for sustainability4.

The above evidence indicates that stocks in the Tasmanian Eastern Zone are unlikely to be recruitment overfished and that the current level of fishing mortality is unlikely to cause these stocks to become recruitment overfished.

On the basis of the evidence provided above, the Tasmanian Eastern Zone Fishery management unit is classified as a sustainable stock.

Tasmanian Northern Zone Fishery

The geographic variability in dynamics within the Tasmanian Northern Zone are reflected by three different LMLs (120 mm, 127 mm and 132 mm)4. Regional catch and catch rates have varied between 2000 and 2015 as a function of changing market preference and adaptive management (that is, effort redistribution and change in LML). The majority of abalone landed from this zone are traditionally unsuited to the live market, and are processed for canned or frozen markets. In 2008, the first of two industry-driven experimental fisheries to improve fish quality commenced in Block 5 with a reduction in LML from 132–127 mm and a 50 t increase in catch, and a second industry-driven experimental fishery commenced in Block 49 in 2011, pushing the TACC for the Northern Zone to a peak of 402.5 t. This initiative was not successful31, and has had longer-term negative impacts on biomass. SCPUE varies across different geographic regions within the Northern Zone, but SCPUE for the zone has fallen in all the key fishing grounds targeted in the industry program over the past 5 years despite TACC reductions in 2012, 2013 and 201428, and again in 20154. The mean SCPUEcw in 2007 prior to the industry experiments was 93.1 kg per hour at a TACC of 280 t, compared with a mean SCPUEcw of 62.4 kg per hour in 2015 at a TACC of 224 t4. The rate of decline in SCPUE since 2012 has been sharp despite consecutive TACC reductions. The zone-wide proxy for biomass is 2.5, marginally above the LRP, while the proxy for fishing mortality is -2.5, which is below the TRP for sustainability4.

The above evidence indicates that the current level of fishing pressure is likely to cause this stock to become recruitment overfished.

On the basis of the evidence provided above, the Tasmanian Northern Zone Fishery management unit is classified as a transitional–depleting stock.

Tasmanian Western Zone Fishery

The Tasmanian Western Zone Fishery management unit has a LML of 140 mm. In 1993–99, the majority of the Western Zone was under-fished (ranging from 500–750 t) in preference to the Eastern Zone where a higher beach price could be achieved, leading to substantial accumulation of biomass and very high catch rates (1993 mean SCPUEcw 104.5 kg per hour; 1999 mean SCPUEcw 163.0 kg per hour). With the introduction of zones in 2000–01 to manage the distribution of effort, the Western Zone TACC was elevated to 1260 t4, and remained at this level through to 2008, with mean SCPUEcw declining to below 130 kg per hour. Widespread selective fishing, considered to be damaging to the resource at this time, along with long-term declines in SCPUE led to the zonal restructure described above and implementation of spatial catch caps set annually for four broad geographic regions within this zone, to prevent excess catch being harvested due to economic pressures. The TACC in this management unit was reduced in 2009 to 924 t. In 2013, Blocks 7 and 8 where moved from the Central Western Zone, back into the Western Zone and the TACC increased to 1001 t associated with the increased fishing area, but effectively retaining the same level of catch as in 201217. In 2013, mean SCPUEcw declined to 111.7 kg per hour triggering a TACC reduction to 840 t in 2014, and held for 2015, with the TACC to be reviewed late in 2016 28. The zone-wide proxy for biomass is 2.5, marginally above the LRP, while the proxy for fishing mortality is -2.1, which is below the TRP for sustainability4.

The above evidence indicates that the current level of fishing pressure is likely to cause this stock to become recruitment overfished.

On the basis of the evidence provided above, the Tasmanian Western Zone Fishery management unit is classified as a transitional–depleting stock.

South Australian Central Zone Fishery

In the Central Zone Fishery management unit of South Australia, CPUE for Blacklip Abalone increased rapidly from 19 kg per hour in 1979 to 26 kg per hour in 1989, the highest level on record. In 1990–2003, CPUE was relatively stable, but variable between years. Recent CPUE peaks were 25 kg per hour in 2003 and 22 kg per hour in 2009, after which CPUE declined substantially to a mean of 19 kg per hour for the years 2012–14. These were the lowest consecutive values since 1985 and occurred despite 40 per cent reductions in the TACC since 2004, culminating in the lowest catch since 198413. However, this recent CPUE was similar to the average since 1979.

 

Based on similar evidence to that presented above, the Central Zone Blacklip Abalone fishery was classified as transitional–depleting in 201414. There is some evidence to suggest that Blacklip Abalone stocks may be improving13. This evidence includes: 1) the increase in CPUE between 2014 and 2015 for the Central Zone and the West Kangaroo Island fishing grounds; and 2) an increase in the proportion of small Blacklip Abalone harvested that, in conjunction with this CPUE increase, may reflect improved recruitment to the fishable stock. In contrast, much of the available evidence, including: 1) the low recent and current catches harvested at relatively low catch rates; 2) limited evidence of stock recovery despite substantial (40 per cent) reductions in the TACC in 2005–06; 3) recent low and/or declining catch rates in the main fishing grounds; 4) apparent spatial contraction of the fishery from a previously larger fished area; and 5) record low catches (about 1 t meat weight) from the South Kangaroo Island fishing grounds, an area that regularly supported catches in excess of 5 t per year (meat weight) between 1980 and 2000, indicates that Blacklip Abalone stocks may still be subject to overfishing13. The above evidence indicates that the biomass of this stock is unlikely to be recruitment overfished, but that the current level of fishing pressure may be likely to cause the stock to become overfished.

 

On the basis of the evidence provided above, the South Australia Central Zone Fishery management unit remains classified as a transitional–depleting stock.

South Australian Southern Zone Fishery

The CPUE for Blacklip Abalone in the Southern Zone Fishery management unit of South Australia increased from 64 kg per hour in 1979–80 to more than 107 kg per hour in 2010–11, the highest level on record. CPUE has subsequently declined, but remains above the long-term average since 1979–80; in 2014–15, CPUE was 90 kg per hour, 16 per cent below that in 2010–11 and at the lowest level since 2001–0232. Similar reductions in CPUE occurred across all fishing grounds32. In addition, the TACC was under-caught in 2013-14 (by 17 per cent) and 2014–15 (by 11 per cent)32. For the period from 2010–11 to 2014–15, the biomass declined, although the stock is not yet considered to be in a recruitment overfished state. The above evidence indicates that the current level of fishing pressure is likely to cause the stock to become recruitment overfished.

 

On the basis of the evidence provided above, the South Australia Southern Zone Fishery management unit is classified as a transitional–depleting stock.

South Australian Western Zone Fishery

The CPUE for Blacklip Abalone in the Western Zone Fishery management unit of South Australia increased from 17.1 kg per hour in 1979 to more than 26 kg per hour in 2003, the highest level on record. Subsequently, CPUE has decreased each year: in 2014–15, CPUE was 19 kg per hour, 27 per cent below that in 2003, and the lowest since 198914. Similar reductions in CPUE occurred across all fishing grounds14. In addition, the total catch in 2015 was 21 per cent below the TACC, reflecting a voluntary reduction in catch by the commercial sector to reduce fishing mortality14. The above evidence indicates that, for the period from 2003–15, the biomass declined and that the current level of fishing pressure is likely to cause the stock to become recruitment overfished.

 

On the basis of the evidence provided above, the South Australia Western Zone Fishery management unit is classified as a transitional–depleting stock.

Toggle content

Biology

Biology
Species Longevity / Maximum Size Maturity (50 per cent)
Blacklip Abalone 20–50 years; 150–220 mm SL  ~ 5 years; 80–130 mm SL 

Blacklip Abalone biology

Toggle content

Distributions

Distribution of reported commercial catch of Blacklip Abalone

Toggle content

Tables

Fishing methods
Western Australia New South Wales Victoria Tasmania South Australia
Commercial
Unspecified
Diving
Indigenous
Diving
Recreational
Diving
Management methods
Method Western Australia New South Wales Victoria Tasmania South Australia
Commercial
Limited entry
Size limit
Spatial closures
Total allowable catch
Indigenous
Bag limits
Section 31 (1)(c1), Aboriginal cultural fishing authority
Size limit
Spatial closures
Recreational
Bag limits
Size limit
Spatial closures
Active vessels
Western Australia New South Wales Victoria Tasmania South Australia
29 in NSWAF 22 in VCZF, 17 in VEZF, 7 in VWZF 55 in TBSZF, 51 in TCWZF, 97 in TEZF, 62 in TNZF, 91 in TWZF 5 in SACZF, 6 in SASZF, 22 in SAWZF
NSWAF
New South Wales Abalone Fishery (NSW)
SACZF
South Australian Central Zone Fishery (SA)
SASZF
South Australian Southern Zone Fishery (SA)
SAWZF
South Australian Western Zone Fishery (SA)
TBSZF
Tasmanian Bass Strait Zone Fishery (TAS)
TCWZF
Tasmanian Central Western Zone Fishery (TAS)
TEZF
Tasmanian Eastern Zone Fishery (TAS)
TNZF
Tasmanian Northern Zone Fishery (TAS)
TWZF
Tasmanian Western Zone Fishery (TAS)
VCZF
Victorian Central Zone Fishery (VIC)
VEZF
Victorian Eastern Zone Fishery (VIC)
VWZF
Victorian Western Zone Fishery (VIC)
Catch
Western Australia New South Wales Victoria Tasmania South Australia
Commercial 129.34t in NSWAF 324.89t in VCZF, 384.54t in VEZF, 58.11t in VWZF 69.77t in TBSZF, 51.88t in TCWZF, 522.02t in TEZF, 225.59t in TNZF, 830.99t in TWZF 19.22t in SACZF, 172.60t in SASZF, 197.54t in SAWZF
Indigenous Unknown Zero Unknown Unknown
Recreational Unknown Unknown 36t Unknown
NSWAF
New South Wales Abalone Fishery (NSW)
SACZF
South Australian Central Zone Fishery (SA)
SASZF
South Australian Southern Zone Fishery (SA)
SAWZF
South Australian Western Zone Fishery (SA)
TBSZF
Tasmanian Bass Strait Zone Fishery (TAS)
TCWZF
Tasmanian Central Western Zone Fishery (TAS)
TEZF
Tasmanian Eastern Zone Fishery (TAS)
TNZF
Tasmanian Northern Zone Fishery (TAS)
TWZF
Tasmanian Western Zone Fishery (TAS)
VCZF
Victorian Central Zone Fishery (VIC)
VEZF
Victorian Eastern Zone Fishery (VIC)
VWZF
Victorian Western Zone Fishery (VIC)

Indigenous (management methods)a,b

a In Victoria, managing fishing activities by Indigenous people is grouped with the recreational fishing sector. Recognised Traditional Owners (groups that hold native title or have agreements under the Traditional Owner Settlement Act 2010 [Vic]) can apply for permits under the Fisheries Act 1995 (Vic) that authorise customary fishing (for example, different catch and size limits or equipment). The Indigenous category in Table 3 has been interpreted to mean customary fishing being undertaken by Recognised Traditional Owners.

b 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.

 

c New South Wales – Indigenous Aboriginal cultural fishing authority - the authority that Indigenous persons can apply to take catches outside the recreational limits under the Fisheries Management Act 1994 (NSW), Section 37 (1)(c1), Aboriginal cultural fishing authority.

Toggle content

Catch Chart

Commercial catch of Blacklip Abalone

Toggle content

Effects of fishing on the marine environment

  • Blacklip Abalone are hand-selected by divers operating from vessels that seldom anchor, hence the fishery has negligible direct physical impact on the environment. There is also substantial evidence that the ecosystem effects of removing abalone are minimal34–36.
Toggle content

Environmental effects on Blacklip Abalone

  • AVG established in the wild fishery following initial infection in two land-based abalone aquaculture farms and two offshore experimental farms adjacent to the wild fishery in 200524. AVG is highly pathogenic, resulting in estimated mortalities of between 60 and 95 per cent in infected wild populations.
  • South and westward strengthening of the relatively oligotrophic East Australian Current37 into the inshore waters in eastern Victoria and Tasmania is thought to have triggered changes in nearshore community structure over the past two decades38. This is primarily through range expansion of species such as the Long Spined Sea Urchin (Centrostephanus rodgersii) from New South Wales to Tasmania and Victoria, and the significant reduction in Giant Kelp (Macrocystis porifera) biomass39. This has resulted in localised depletions of abalone populations and a reduction in the habitat available for abalone40.
  • Above average warm water events were inferred to have resulted in minor mortalities of abalone in Tasmania in February 2010 (pers. comm., Tasmanian Abalone Divers), although the spatial extent and magnitude of the mortality was not quantified. These events are expected to increase under most climate change scenarios.
Toggle content

References

  1. 1 Prince JD, Sellers TL, Ford WB, Talbot SR. 1987, Experimental-Evidence for Limited Dispersal of Haliotid Larvae (Genus Haliotis, Mollusca, Gastropoda). Journal of Experimental Marine Biology and Ecology 1987; 106: 243–263. .
  2. 2 Miller KJ, Maynard BT, Mundy CN. 2009, Genetic diversity and gene flow in collapsed and healthy abalone fisheries. Molecular Ecology 2009; 18: 200–211. .
  3. 3 Temby N, Miller K, Mundy C. 2007, Evidence of genetic subdivision among populations of blacklip abalone (Haliotis rubra Leach) in Tasmania. Marine and Freshwater Research 2007; 58: 733–742. .
  4. 4 Mundy C, Jones HJ. 2016, Tasmanian Abalone Fishery Assessment 2015. Institute for Marine and Antarctic Studies Report. University of Tasmania, Hobart.
  5. 5 Hart. 2016, Review of fixed site surveys used by the Victorian abalone science program. Western Australian Department of Fisheries.
  6. 6 Gorfine H, Taylor B, Smith DC. 2002, Abalone – 2001, Fisheries Victoria Assessment Report No 43. Marine and Freshwater Resources Institute, Queenscliff.
  7. 7 Buxton CD, Cartright I, Dichmont C, Mayfield S, Plaganyi EE. 2015, Review of the Harvest Strategy and MCDA process for the Tasmanian Abalone Fishery. Institute for Marine and Antarctic Studies.
  8. 8 Mundy C, Jones HJ. 2016, Multi-Criteria Decision Analysis based harvest strategy for the Tasmanian abalone fishery. Institute for Marine and Antarctic Studies, Hobart.
  9. 9 Haddon M, Mundy C. 2016, Testing abalone empirical harvest strategies, for setting TACs and associated LMLs, that include the use of novel spatially explicit performance measures. CSIRO Oceans and Atmosphere, Hobart.
  10. 10 Haddon M, Mayfield S, Helidoniotis F, Chick R, Mundy C. 2014, Identification and Evaluation of Performance Indicators for Abalone Fisheries. FRDC Final Report 2007/020. Commonwealth Scientific and Industrial Research Organisation (CSIRO), Hobart http://frdc.com.au/research/Final_reports/2007-020-DLD.pdf.
  11. 11 Jones HJ, Pyke S, Mundy C. 2016, Review of Size at Maturity and Legal Minimum Length in Tasmanian Blacklip Abalone Fisheries. Institute for Marine and Antarctic Studies Report. University of Tasmania, Hobart.
  12. 12 PIRSA. 2012, Management Plan for the South Australian commercial abalone fishery. 2012. .
  13. 13 Burnell O, Mayfield S, Ferguson G, Carroll J. 2016, Central Zone Abalone (Haliotis laevigata & H. rubra) Fishery. Fishery Assessment Report for PIRSA Fisheries and Aquaculture. 2016.
  14. 14 Stobart B, Mayfield S. 2016, Status of the Western Zone Blacklip Abalone (Haliotis rubra) fishery in 2015. Report for PIRSA Fisheries and Aquaculture. 2016. .
  15. 15 Dowling NA, Hall SJ, McGarvey R. 2004, Assessing population sustainability and response to fishing in terms of aggregation structure for greenlip abalone (Haliotis laevigata) fishery management. Canadian Journal of Fisheries and Aquatic Science 2004; 61: 247–259. http://www.nrcresearchpress.com/doi/abs/10.1139/f03-165#.WDdkrlzx0Uc.
  16. 16 Stobart B, Mayfield S. 2016, Assessment of the Western Zone greenlip abalone (Haliotis laevigata) Fishery in 2015. Fishery Stock Assessment Report to PIRSA Fisheries and Aquaculture. 2016. .
  17. 17 Tarbath D, Mundy C, Gardner C. 2014, Tasmanian Abalone Fishery Assessment 2013. Institute for Marine and Antarctic Studies .
  18. 18 Shephard S, Rodda KR. 2001, Sustainability demands vigilance: Evidence for serial decline of the greenlip abalone fishery and a review of management. 2001; 20: 829–841. .
  19. 19 Anon. 2015, Total Allowable Catch Committee Report and Determination for 2016 – Abalone Fishery 2015. New South Wales Government.
  20. 20 Liggins G, Upston J. 2010, Investigating and managing the Perkinsus-related mortality of Blacklip Abalone in NSW. 2010. .
  21. 21 DEDJTR. 2016, Victorian Abalone Stock Assessment – Central Zone. Fisheries Victoria.
  22. 22 Gorfine H, Bell J, Mills K, Lewis Z. 2012, Removing sea urchins (Centrostephanus rodgersii) to recover abalone (Haliotis rubra) habitat. Department of Primary Industries, Queenscliff, Victoria, Australia.
  23. 23 DEDJTR. 2016, Victorian Abalone Stock Assessment – Eastern Zone. Fisheries Victoria.
  24. 24 Mayfield S, McGarvey R, Gorfine HK, Peeters H, Burch P, Sharma S. 2011, Survey estimates of fishable biomass following a mass mortality in an Australian molluscan fishery. Journal of Fish Diseases 2011; 34: 287–302. .
  25. 25 Helidoniotis F, Haddon M. 2014, Modelling the potential for recovery of Western Victorian abalone stocks: The Crags. Interim Report to 2012/225. CSIRO, Hobart.
  26. 26 Gorfine H, Day R, Bardos D, Taylor B, Prince J, Sainsbury K et al. 2008, Rapid response to abalone virus depletion in western Victoria: information acquisition and reefcode assessment, final report to the Fisheries Research and Development Corporation, project 2007-066. The University of Melbourne .
  27. 27 WADA. 2016, Assessment of abalone stocks in Western Zone, Victoria: Submission to the TAC setting process for 2017 November 2016. WADA.
  28. 28 Tarbath D, Mundy C. 2015, Tasmanian Abalone Fishery Assessment 2014. Institute for Marine and Antarctic Science, University of Tasmania .
  29. 29 Tarbath D, Mundy C. 2004, Tasmanian Abalone Fishery 2003. Tasmanian Aquaculture and Fisherieis Institute .
  30. 30 Tarbath D, Gardner C. 2011, Tasmanian Abalone Fishery Assessment 2010. Tasmanian Aquaculture and Fisheries Institute .
  31. 31 Jones C H. J. Tarbath D. Gardner. 2014, Could harvest from abalone stocks be increased through better management of the size limit/quota interaction? Australian Seafood Cooperative Research Centre, Institute for Marine and Antarctic Studies, University of Tasmania .
  32. 32 Ferguson G, Mayfield S. 2016, Status of the Southern Zone blacklip (Haliotis rubra) and greenlip (H. laevigata) abalone fisheries in 2014/15. Report for PIRSA Fisheries and Aquaculture. 2016.
  33. 33 Lyle JM, Tracey SR. 2016, Tasmanian Recreational Rock Lobster and Abalone Fisheries: 2014-2015 Fishing Season. 2016. .
  34. 34 Jenkins GP. 2004, The ecosystem effects of abalone fishing: a review. Marine and Freshwater Research 2004; 55: 545–552.
  35. 35 Valentine JP, Tarbath DB, Frusher SD, Mundy CN, Buxton CD. 2010, Limited evidence for ecosystem-level change on reefs exposed to Haliotis rubra (“blacklip abalone”) exploitation. Austral Ecology 2010; 35: 806–817. .
  36. 36 Hamer PA, Jenkins G, Womersley BA, Mills KA. 2010, Understanding the ecological role of abalone in the reef ecosystem of Victoria. Final report to Fisheries Research and Development Corporation. Project No. 2006/040. 2010. .
  37. 37 Ridgway KR. 2007, Long-term trend and decadal variability of the southward penetration of the East Australian Current. Geophysical Research Letters 2007; 34. .
  38. 38 Johnson CR, Banks SC, Barrett NS, Cazassus F, Dunstan PK, Edgar GJ et al. 2011, Climate change cascades: Shifts in oceanography, species’ ranges and subtidal marine community dynamics in eastern Tasmania. Journal of Experimental Marine Biology and Ecology 2011; 400: 17–32. .
  39. 39 Ling SD, C.R. J, K. R, Hobday A, Haddon M. 2009, Climate-driven range extension of a sea urchin: inferring future trends by analysis of recent population dynamics. Global Change Biology 2009; 15: 719–731. .
  40. 40 Strain EMA, Johnson CR. 2009, Competition between an invasive urchin and commercially fished abalone: effect on body condition, reproduction and survivorship. Mar Ecol Prog Ser 2009; 377: 169–182.

Archived reports

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nunc vel ornare magna, nec viverra ante. Ut in ipsum tellus.