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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. 

New South Wales

The New South Wales Abalone Fishery is managed as a single jurisdictional stock with a single total allowable commercial catch (TACC). However, assessment of the stock is done at the scale of four geographically defined Spatial Management Units (SMUs), and a whole of stock status is not defined within the assessment. Assessments rely on fishery-dependent data from commercial fisher logbooks, including catch, catch rate (whole weight, kg per hour) and mean weight (catch divided by the number of abalone harvested). More recent assessments also derive estimates of fishery and stock performance from GPS logger data and data from logbooks, including measures of legal-size biomass density (kg per hectare) and productive area of reef (i.e. cumulative area fished in the most recent three years) to estimate legal-size biomass.

Blacklip Abalone stocks continue to recover from historical overfishing [Liggins and Upston 2010, TACSRC 2017, TAFC 2018]. Historical stock status, inferred largely from differences in catch rate, indicate stocks were subject to recruitment overfishing and were depleted 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). TACCs and annual catches exceeded 330 t throughout the 1990s, were reduced during the early 2000s from 305 to 130 t and further reduced, reaching the lowest level of 75 t, in 2009–10, during which time the legal minimum length (LML) was also increased [NSW DPI unpublished]. Subsequently, catch rate and mean weight of abalone increased to levels not previously recorded. In 2010, catch rate exceeded 30 kg per hour for the first time since the early 1980s and was >45 kg per hour in 2014, at or among the highest levels recorded. These changes in catch and catch rate together with increased levels of legal-size biomass density (kg per hectare) indicated legal-size biomass had about doubled over this period [TAFC 2018, NSW DPI 2020], and the TACC was incrementally increased, reaching 130 t in 2015. However, from about 2015 to 2018–19, stock productivity declined, partially owing to extreme sea conditions causing high abalone mortality in mid-2016, but catch levels were maintained. This combination of relatively high catch rates and reduced productivity lead to depletion of biomass to levels similar to those of 2011–12 (catch rate ~40 kg per hour and reduced legal-size biomass). These patterns were consistent among the three (of a total of four) most significant (consistently >95 per cent of total catch) SMUs (i.e. SMUs 2, 3, and 4). The TACC was reduced to 100 t in 2018, and has been maintained at that level [NSW DPI 2020]. In 2019–20, increased catch rates and legal-size biomass density in SMU 2 and SMU 3 indicate an arrest of the depletion of biomass rebuilt during 2009–14. Similar changes are not evident in SMU 4 [NSW DPI unpublished, TAFC 2018]. Persistence or an increase in current measures of stock performance beyond the one or two current years would provide greater certainty in the determination of a sustainable stock status in SMU 2 and 3. However, continued declines in catch rate and legal-size biomass in 2019–20 in SMU 4, to levels similar to those in 2010–13, indicate continued depletion of biomass and decline in stock status in this SMU, despite management interventions [NSW DPI unpublished].

The most northern areas of the State (SMU 1), which have typically contributed ≤ 10 percent of the total annual catch over at least the last decade, were subject to high fishing mortality through the mid-1980s to the early-1990s, then further depleted by mortality associated with infection by the parasite Perkinsus sp. from the 1990s to the early-2000s [Liggins and Upston 2010, TACSRC 2015]. Fishery-dependent data have not indicated recovery of these stocks to historical levels [TACSRC 2017].

In addition to TACC changes, protection for the stock has been achieved through several increases in the LML from 100 mm established in 1972, through four increases to 117 mm in 2008 (for all fishing sectors), 118 mm in 2018 and 120 mm in 2019 (commercial sector only). In the most southern areas of the state, the LML for the commercial fishery was increased to 120 mm in 2010, 123 mm in 2013 and 125 mm in 2018. It is estimated that these changes have resulted in 27 per cent fewer abalone commercially harvested in 2019–20 than in 2017–18 [NSW DPI unpublished]. Mean weight of commercially harvested Blacklip Abalone has generally increased through time since about 2008, consistent with changes to the LML.

Fishery-dependent data (catch, catch rate and legal-size biomass) have supported recent changes in stock status and together with substantial contrast to historical levels, provide information to infer historical status, reference levels of catch rate and a relative measure of stock abundance through time. However, there is no formal harvest strategy describing reference points from which stock status can be directly defined, either at the whole fishery or SMU scale.

The evidence presented above indicates that the Blacklip Abalone stock in New South Wales was overfished through the mid-1980s and into the early-2000s. After the early-2000s, management measures supported strong stock rebuilding through to 2014–15. Whereafter, stocks declined through to about 2018–19 in SMU 2 and 3, and into 2019–20 in SMU 4. Recent management measures, including the TACC reduction (to 100 t in 2018, maintained to the current fishing period 2020–21 [NSW DPI 2020]) and increases to LMLs have reduced fishing mortality, evidenced by recent measures of fishery performance in SMU 2 and 3 that are more consistent with a sustainable stock status. However, fishing mortality has remained too high in SMU 4 and its persistence is likely to cause the stock in this SMU to become recruitment impaired. These contrasts in fishery-dependent measures of stock performance among SMUs, together with recent changes in some fisher operations (e.g. fishing to specific markets) and impacts on fishing operations and markets from bushfires (declared a natural disaster in NSW in 2019) and the COVID-19 pandemic, provide further uncertainty to the current and future assessments, including the determination of stock status [NSW DPI unpublished], and preclude determination of a stock status of sustainable with reasonable confidence. A fishery harvest strategy that provides clear guidance on the measures used and criteria for determination of fishery stock status is critical for improved transparency and certainty in decision making.

On the basis of the evidence provided above, Blacklip Abalone in New South Wales is classified as an undefined 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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