Small Pelagic Fishery

​​​​​Chapter 7: Small Pelagic Fishery

N Marton and D Mobsby.

Figure 7.1 Area fished in the Small Pelagic Fishery, 2017–18

Note: Some effort data are not shown on this map for confidentiality reasons.

Table 7.1 Status of the Small Pelagic Fishery
 2016 2017Comments
Status Biological statusFishing
mortality
BiomassFishing
mortality
Biomass 
Australian sardine
(Sardinops sagax)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfishedRecent catches have been below the RBC. Historical catches have been low and are not likely to have reduced biomass below the limit reference point.
Blue mackerel, east
(Scomber
australasicus
)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfishedMost recent catches have been below the RBC. Historical catches have been low and are not likely to have reduced biomass below the limit reference point.
Blue mackerel, west
(Scomber
australasicus
)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfishedRecent catches have been below the RBC. Historical catches have been low and are not likely to have reduced biomass below the limit reference point.
Jack mackerel, east
(Trachurus declivis)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfishedRecent catches have been below the RBC. Recent historical catches have been low and are not likely to have reduced biomass below the limit reference point.
Jack mackerel, west
(Trachurus declivis)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfishedRecent catches have been below the RBC. Historical catches have been low and are not likely to have reduced biomass below the limit reference point.
Redbait, east
(Emmelichthys nitidus)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfishedRecent catches have been below the RBC. Historical catches have been low and are not likely to have reduced biomass below the limit reference point.
Redbait, west
(Emmelichthys nitidus)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfishedRecent catches have been below the RBC. Historical catches have been low and are not likely to have reduced biomass below the limit reference point.
Economic statusEstimates of NER are not available for 2016–17. A decrease in the level of catch in 2016–17 compared with the very high level of catch in 2015–16 suggests that gross value of production is likely to have declined in 2016–17. Changes in NER are uncertain because of a lack of information about changes in cost structures of the industry.

Notes: NER Net economic returns. RBC Recommended biological catch.

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7.1 Description of the fishery

Area fished

The Small Pelagic Fishery (SPF) extends from southern Queensland to southern Western Australia (Figure 7.1). The fishery has three subareas, each with its own total allowable catch (TAC).

Fishing methods and key species

The fishery includes purse-seine and midwater trawl fishing vessels. The key target species for the purse-seine vessels are Australian sardine (Sardinops sagax),blue mackerel (Scomber australasicus)and jack mackerel (Trachurus declivis)The key target species for the midwater trawl fishery are blue mackerel,jack mackerel and redbait (Emmelichthys nitidus).

Management methods

Almost all small pelagic stocks are multijurisdictional (that is, managed by both the Australian and state governments) under Offshore Constitutional Settlement arrangements. The exception is the western stock of Australian sardine, which is managed by South Australia and Victoria.

Management of the SPF is operationalised through a harvest strategy that has been revised several times in recent years. The review of the 2014 harvest strategy (AFMA 2014) included ecosystem and population modelling (Smith et al. 2015). Recommendations from the review were incorporated into the current harvest strategy (AFMA 2017a), which adopts a target reference point of 0.5B0 (50 per cent of the unfished biomass) and a limit reference point of 0.2B0.

The harvest strategy has three tiers, with static exploitation rates for each tier and species. Operating at tier 1 requires a recent egg survey and a biomass estimate based on the daily egg production method (DEPM). Tier 1 allows for the highest exploitation rates (Table 7.2). A tier 1 recommended biological catch (RBC) can be set for a maximum of five seasons after the egg survey and DEPM biomass estimate, and, if an updated survey is not conducted, the harvest strategy steps down to tier 2. Tier 2 has reduced exploitation rates in acknowledgement of the increasing uncertainty over time of how well the DEPM reflects current biomass. Similarly, the harvest strategy steps down from tier 2 to tier 3 after a further 5 or 10 years (depending on the species), with a further reduced exploitation rate. Stocks without a DEPM-based biomass estimate have a further reduced exploitation rate but are still classified as tier 3. Redbait (west) is now the only SPF stock without a DEPM-based biomass estimate; biomass is instead estimated using the Atlantis-SPF ecosystem model.

Table 7.2 SPF harvest strategy tier levels when stocks have a DEPM-based biomass estimate
StockTier 1Tier 2Tier 3 aYear of 
most
recent egg survey
Max. 
exploitation rate (%)
Max. timeat rate(seasonsMax. 
exploitation
rate (%)
Max. time at rate (seasons)Max.
exploitation 
rate (%)
Australian sardine 20 5 10 5 5 2014
Blue mackerel, east 15 5 7.5 5 3.75 2015
Blue mackerel, west 15 5 7.5 5 3.75 2005
Jack mackerel, east 12 5 6 10 3 2014
Jack mackerel, west 12 5 6 10 3 2016
Redbait, east 10 5 5 10 2.5 2006
Redbait, west b10 5 5 10 2.5 None

a No time limit applies for a stock at tier 3. b Maximum exploitation rate is currently 1.25% of the Atlantis-SPF
ecosystem-based biomass estimate because there is no DEPM biomass estimate.
Note: DEPM Daily egg production method.

Biomass is difficult to estimate for small pelagic species that exhibit high interannual variability. Where DEPM biomass estimates are available, a key assumption for assessing small pelagic stocks is that these estimates are a reliable indicator of abundance. However, outputs from DEPM surveys can have large confidence intervals (CIs). In this chapter, spawning biomass estimates are generally presented with the 95 per cent CI of the range of possible estimates. Because these ranges are often broad and there is a possibility that spawning biomass might be outside these ranges, great caution needs to be taken when interpreting fishing mortality and biomass against specified limit and target reference points. If fishing mortality approaches RBCs, it may be necessary to consider alternative scenarios of estimated spawning biomass to assess risks to small pelagic stocks.

Fishing effort

Most historical fishing effort occurred off the east and west coasts of Tasmania. Purse seining was the main method, but has been replaced by midwater trawling since 2002. Effort in the SPF increased in 2014–15, 2015–16 and 2016–17 with the operation of a factory trawler. This vessel has since left Australian waters (AFMA 2016a).

Catch

Small pelagic fish are generally caught during targeted fishing for a single species. They are also caught in small quantities in other Commonwealth- and state-managed fisheries, including the Southern and Eastern Scalefish and Shark Fishery, the Eastern Tuna and Billfish Fishery, the Western Tuna and Billfish Fishery, and the New South Wales Ocean Hauling Fishery.

Catch in the SPF increased from around 6,000 t in 1984–85 to a peak of almost 42,000 t in 1986–87. Average catches of around 12,000 t per year were also taken in the early 1990s, comprising mostly redbait. Until recently, minimal catch and effort in the Commonwealth SPF have reflected a lack of markets and processing facilities. The operation of a factory trawler in the 2014–15, 2015–16 and 2016–17 seasons led to increased catches. After the factory trawler left the fishery during the 2016–17 season (AFMA 2016a), catches decreased.

Table 7.3 Main features and statistics for the SPF
Fishery statistics a

2016–17 fishing season

2017–18 fishing season
Stock nameTAC 
(t)
Catch 
(t)
Real value (2016–17)TAC 
(t)
Catch 
(t) b
Australian sardine 1,880 131 Confidential 9,550 97
Blue mackerel, east 2,630 1,248 Confidential 12,090 2,858
Blue mackerel, west 6,200 766 Confidential 3,230
Jack mackerel, east 18,670 3,966 Confidential 18,880 2,748
Jack mackerel, west 3,600 686 Confidential 920
Redbait, east 3,310 101 Confidential 3,410 10
Redbait, west 2,880 1,140 Confidential 820
Total fishery 39,170 8,038 Confidential 48,900 5,713

Fishery-level statistics

Effort Purse seine: 133 search-hours

Midwater trawl: 184 shots

Purse seine: 152 search-hours

Midwater trawl: 223 shots

Fishing permits 32 entities held quota SFRs in 2016–17

30 entities held quota SFRs in 2017–18

Active vessels Purse seine: 2

Midwater trawl: 1

Purse seine: 2

Midwater trawl: 1

Observer coverage Purse seine: 0%

Midwater trawl: 100%

Purse seine: 0%

Midwater trawl: 36%

Fishing methods Purse seine, midwater trawl
Primary landing ports

Iluka, Ulladulla (New South Wales); Geelong, Melbourne (Victoria)

Management methods

Input controls: limited entry, gear restrictions

Output controls: TACs, with ITQs implemented from 1 May 2012

Primary markets

Domestic: fishmeal, bait and human consumption

International: human consumption

Management plan

Small Pelagic Fishery Management Plan 2009

a Fishery statistics are provided by fishing season, unless otherwise indicated. Fishing season is 1 May to 30 April. Real-value statistics are by financial year and are not available for 2017–18.
Notes: ITQ Individual transferable quota. SFR Statutory fishing right. TAC Total allowable catch.

7.2 Biological status

Australian sardine (Sardinops sagax)

Australian sardine (Sardinops sagax)

Line drawing: FAO

Stock structure

Several studies found evidence of stock structuring of Australian sardine across southern Australia (Dixon, Worland & Chan 1993; Izzo, Gillanders & Ward 2012; Yardin et al. 1998); however, the boundaries were not conclusively defined. Izzo et al. (2017), using an integrative assessment including genetic, morphological, otolith, growth, reproductive and fishery data, found evidence for at least four isolated stocks (south-west coast of Western Australia, Great Australian Bight and Spencer Gulf, Bass Strait and Port Phillip Bay, and eastern Australia). Since the sardine subarea (off eastern Australia; Figure 7.1) is the only area of the SPF that is fished, Australian sardine in the SPF is assessed and managed as a single east coast stock.

Catch history

State catches of Australian sardine comprise most of the total catch. Unlike in the Commonwealth fishery, state catches are not constrained by catch limits. State catches increased substantially from 2001–02 to 2009–10, contributing to reductions to the Commonwealth TAC. Total sardine catch from Commonwealth and state fisheries (other than that taken in South Australia) peaked in 2007–08 at 4,619 t and decreased to 894 t in 2014–15—its lowest level since 2001–02. Catch increased to 2,887 t in 2016–17, primarily driven by increased catches by the Victorian fleet. The Commonwealth catch for 2017–18 was 97 t (Figure 7.2); state catches are not available for 2017–18.

Figure 7.2 Commonwealth Australian sardine catch and TAC in the SPF, 2003–04 to 2017–18
Note: TAC Total allowable catch.
Stock assessment

Egg surveys for the east coast stock of Australian sardine and eastern blue mackerel were conducted concurrently in August–September 2014. For Australian sardine, a spawning biomass of 49,600 t (95 per cent CI 24,200–213,300 t) was estimated with the DEPM (Ward et al. 2015b).

Although the 2014 DEPM result was available for use for both the 2015–16 and 2016–17 seasons, results from the previous DEPM estimate (Ward et al. 2007) were used. This was to allow for additional testing (including a management strategy evaluation [MSE]) on the SPF harvest strategy in use at that time. The SPF Scientific Panel used the 2014 DEPM estimate for the first time in 2017 to recommend a 2017–18 RBC of 9,915 t, using tier 1 of the 2017 harvest strategy. After factoring in state catches, the Australian Fisheries Management Authority (AFMA) Commission agreed to a TAC of 9,550 t.

The 2015 MSE suggested linking harvest strategy settings to the productivity of the species (Smith et al. 2015). For Australian sardine, it was suggested that tier 1 harvest rates could be increased from 15 per cent to 33 per cent, that tier 2 harvest rates should be set at 50 per cent of tier 1, and that neither should be applied for longer than five years (Smith et al. 2015). A tier 1 harvest rate of 20 per cent was formally adopted in the 2017 SPF harvest strategy. This lower harvest rate reflects uncertainty in some of the life-history characteristics for the eastern Australian sardine stock and differences from the rate applied for the South Australian Sardine Fishery (25 per cent) (AFMA 2015a). Also, adopting a 33 per cent harvest rate would have been a considerable increase on the rate at the time (AFMA 2015a). Additionally, Smith et al. (2015) noted that there was some concern around the level of risk for breaching the B20 limit reference point if regular egg surveys were not conducted.

The most recent available state catch data are for 2016–17, when the total catch (state and Commonwealth) was 2,887 t. This equates to 5.8 per cent of the 2014 biomass estimate (Ward et al. 2015b). Total Commonwealth catch (that is, excluding state catch) in 2017–18 was 97 t, which equates to 0.2 per cent of the 2014 biomass estimate.

Stock status determination

The peak historical catch from this stock was 9.3 per cent of the 2014 spawning biomass estimate and was taken in 2007–08. Catches have remained low as a proportion of estimated spawning biomass. This level of fishing mortality is unlikely to have substantially reduced spawning biomass. Australian sardine is therefore classified as not overfished. Fishing mortality remains a small proportion of estimated biomass, and was below the 2017–18 RBC and TAC.The stock is therefore classified as not subject to overfishing.

Blue mackerel, east (Scomber australasicus)

Blue mackerel, east (Scomber australasicus)

Line drawing: FAO

Stock structure

The stock structure of blue mackerel is uncertain. Genetic analysis of samples from southern Queensland, Western Australia and New Zealand indicates population subdivision. Genetic differences were detected between Western Australia and Queensland, and between Western Australia and New Zealand, but not between Queensland and New Zealand (Schmarr et al. 2007; Whittington, Ovenden & Ward 2012). No finer-scale analyses of blue mackerel have been undertaken to further define stock structure. Blue mackerel within the SPF is assessed and managed as separate stocks in the eastern and western subareas (Figure 7.1).

Catch history

Most of the eastern blue mackerel catch has historically been taken in state fisheries. However, Commonwealth catch exceeded state catch while the factory trawler was operating and continues to be higher. Commonwealth catch has been variable in recent years, but peaked at 2,858 t in 2017–18 (Figure 7.3). Total state and Commonwealth catch peaked at 2,368 t in 2015–16, which is below the 2017–18 Commonwealth catch. State catch is not available for 2017–18. Most eastern blue mackerel catch comes from the Commonwealth fleet.

Figure 7.3 Commonwealth eastern blue mackerel catch and TAC, 2003–04 to 2017–18
Note: TAC Total allowable catch.
Stock assessment

Egg surveys for the eastern stock of blue mackerel and Australian sardine were conducted concurrently in August–September 2014. For eastern blue mackerel, the DEPM estimated a spawning biomass of 83,300 t (95 per cent CI 35,100–165,000 t) (Ward et al. 2015b). However, because samples of adult blue mackerel were not collected during the egg survey, reproductive parameters of adult blue mackerel taken from previous egg surveys off southern Australia between 2001 and 2006 were used. Ward et al. (2015b) therefore suggest that their estimate of spawning biomass be treated with caution.

As for Australian sardine, although the 2014 DEPM estimate was available for use for both the 2015–16 and 2016–17 seasons, results from the previous DEPM estimate (Ward et al. 2007) were used. This was to allow for additional testing (including MSE) of the SPF harvest strategy in use at that time (Pascoe & Hillary 2016; Punt, Little & Hillary 2016). The SPF Scientific Panel used the 2014 DEPM estimate for the first time in 2017 to recommend a 2017–18 RBC of 12,495 t, using tier 1 of the 2017 harvest strategy. After factoring in state catches, the AFMA Commission agreed to a TAC of 12,090 t.

While additional MSE work was conducted for both eastern blue mackerel and eastern jack mackerel, the SPF Scientific Panel recommended retaining the results from the 2015 MSE (AFMA 2016b). The 2015 MSE suggested linking harvest strategy settings to the productivity of the species (Smith et al. 2015). For blue mackerel, it was suggested that tier 1 harvest rates could be increased from 15 per cent to 23 per cent, that tier 2 harvest rates should be set at 50 per cent of tier 1, and that neither should be applied for longer than five years. Smith et al. (2015) noted that there was some concern around the level of risk for breaching the B20 limit reference point if regular egg surveys were not conducted. Additionally, there was some concern around the age structure and reproductive biology parameters available for use in the MSE (AFMA 2015b). As a result, a tier 1 harvest rate of 15 per cent was formally retained in the 2017 SPF harvest strategy.

The most recent year that both state and Commonwealth catch data are available is 2016–17, when the total catch was 1,529 t. This equates to 1.8 per cent of the 2014 biomass estimate (Ward et al. 2015b). Total Commonwealth catch (that is, excluding state catch) in 2017–18 was 2,858 t, which equates to 3.4 per cent of the 2014 biomass estimate.

Stock status determination

Catches have been low as a proportion of the most recent estimated biomass, peaking at 3.4 per cent of the 2014 estimated biomass. This level of fishing mortality is unlikely to have substantially reduced spawning biomass. The eastern blue mackerel stock is therefore classified as not overfished. Fishing mortality remains a small proportion of estimated biomass and was below the 2017–18 RBC and TAC. The stock is therefore classified as not subject to overfishing.

Blue mackerel, west (Scomber australasicus)

Stock structure

See blue mackerel (east).

Catch history

Very little western blue mackerel was caught before 2004–05. Total Commonwealth-landed catch increased in 2005–06, peaking in 2008–09 at 2,164 t and decreasing steadily thereafter. Catch was negligible between 2011–12 and 2013–14 in both the state and Commonwealth fisheries. No Commonwealth catch was reported in 2017–18 (Figure 7.4), and state catches are not available for 2017–18.

Figure 7.4 Commonwealth western blue mackerel catch and TAC, 2004–05 to 2017–18
Note: TAC Total allowable catch.
Stock assessment

An egg survey for western blue mackerel was conducted in 2005 and a spawning biomass of 56,228 t (95 per cent CI 10,993–293,456 t) was estimated using the DEPM (Ward & Rogers 2007). However, the SPF Resource Assessment Group considered this to be too low and adjusted the estimate to 86,500 t.

The 2015 MSE suggested linking harvest strategy settings to the productivity of the species (Smith et al. 2015). For western blue mackerel, it was suggested that tier 1 harvest rates should be set at 23 per cent, that tier 2 harvest rates should be set at 50 per cent of tier 1, and that neither should be applied for longer than five years. Smith et al. (2015) noted that there was some concern around the level of risk for breaching the B20 limit reference point if regular egg surveys were not conducted, and so lower harvest rates were adopted (starting at 15 per cent for tier 1) in the 2017 SPF harvest strategy.

Tier 3 of the 2017 harvest strategy was used to recommend a 2017–18 RBC of 3,243 t. This was the first season that tier 3 was used to set an RBC for western blue mackerel. After factoring in state catches, the AFMA Commission agreed to a TAC of 3,230 t.

Stock status determination

The peak harvest from this stock was approximately 4 per cent of the 2005 spawning biomass estimate (taken in 2008–09), and catches have remained low as a proportion of estimated spawning biomass. Although the 2005 biomass estimate is dated, the level of fishing mortality in any year is unlikely to have substantially reduced spawning biomass. As a result, western blue mackerel is classified as not overfished. Current fishing mortality remains a small proportion of estimated biomass, with no catch in the Commonwealth fishery in 2017–18. The stock is therefore classified as not subject to overfishing.

AFMA

Jack mackerel, east (Trachurus declivis)

Jack mackerel, east (Trachurus declivis)

Line drawing: FAO

Stock structure

The stock structure of jack mackerel is unclear. A study by Richardson (1982) found evidence of population subdivision between Western Australia, including the Great Australia Bight, and eastern Australia. Similarly, a DEPM estimate for western jack mackerel appears to show some stock structuring around the Bonney Coast west of Bass Strait (AFMA 2017c). Richardson (1982) also found evidence of a Wahlund effect (where multiple populations are detected in a single sample) in east coast samples, suggesting some additional structuring. Smolenski, Ovenden & White (1994) found evidence of structuring between New South Wales and south-eastern Tasmania, although the differences appeared not to be temporally consistent. These studies suggest that further investigation of stock structure in jack mackerel on the east coast is warranted. Currently, jack mackerel within the SPF is assessed and managed as separate stocks in the eastern and western subareas (Figure 7.1).

Catch history

The jack mackerel purse-seine fishery was established off Tasmania in the mid 1980s, with initial catches exceeding 40,000 t (Kailola et al. 1993). Catches then declined as a result of an absence of surface schools of jack mackerel, and the purse-seine fishery ceased in 2000 (Ward et al. 2011). Commonwealth catch increased to 9,873 t in 1997–98, fluctuated markedly to 2003–04 and then declined as a result of decreasing effort in the fishery. In recent years, most catch has come from the Commonwealth fleet. Commonwealth catch reached 6,316 t in 2015–16 before decreasing to 2,748 t in 2017–18 (Figure 7.5). State catches are not available for 2017–18.

Figure 7.5 Commonwealth eastern jack mackerel catch and TAC, 2003–04 to 2017–18
Note: TAC Total allowable catch.
Stock assessment

The most recent egg survey for eastern jack mackerel was conducted off eastern Australia in January 2014 (Ward et al. 2015a), and a spawning biomass of 157,805 t (95 per cent CI 59,570–358,731 t) was estimated using the DEPM.

An MSE in 2015 suggested linking harvest strategy settings to the productivity of the species (Smith et al. 2015). For eastern jack mackerel, it was suggested that tier 1 harvest rates should be set at 12 per cent, that tier 2 harvest rates should be set at 50 per cent of tier 1, and that neither should be applied for longer than five years. Additional testing in 2016 was also used to assess harvest rates and target reference points (Pascoe & Hillary 2016; Punt, Little & Hillary 2016). A tier 1 harvest rate of 12 per cent was formally adopted in the 2017 SPF harvest strategy.

The SPF Scientific Panel used the 2014 DEPM estimate to recommend a 2017–18 RBC of 18,937 t, using tier 1 of the 2017 harvest strategy (AFMA 2017b). After factoring in state catches, the AFMA Commission agreed to a TAC of 18,880 t.

The most recent year that state and Commonwealth catch data are available is 2016–17, when the total catch was 3,966 t. This equates to 2.5 per cent of the 2014 biomass estimate (Ward et al. 2015a). Total Commonwealth catch (that is, excluding state catch) in 2017–18 was 2,748 t, which equates to 1.7 per cent of the 2014 biomass estimate.

Stock status determination

The peak catch in this fishery over the past 30 years was 4 per cent of the spawning biomass estimate, with catches in most years being far below this level. This level of fishing mortality is unlikely to have substantially reduced spawning biomass. As a result, eastern jack mackerel is classified as not overfished. Current fishing mortality remains a small proportion of biomass, and below the RBC. The stock is therefore classified as not subject to overfishing.

Jack mackerel, west (Trachurus declivis)

Stock structure

See jack mackerel (east).

Catch history

Total catch (state and Commonwealth) for jack mackerel (west) did not exceed 250 t before 2005–06. Commonwealth catch was zero or negligible from 2011–12 to 2014–15, and increased to 613 t in 2015–16 and 686 t in 2016–17 (Figure 7.6). State catches have been negligible for the past decade.

Figure 7.6 Commonwealth western jack mackerel catch and TAC, 2003–04 to 2017–18
Note: TAC Total allowable catch.
Stock assessment

Between December 2016 and February 2017, western jack mackerel was surveyed to estimate biomass using the DEPM (Ward et al. 2018). Biomass was estimated in a core area and an extended area (into Bass Strait) after opportunistic sampling. Because the extended area showed extensive spawning in Bass Strait it was included in the biomass estimate, but with a caveat that it is underestimated because the area was not extensively sampled. Biomass was initially estimated at 34,978 t (AFMA 2017c) but was revised down to 31,069 t (Ward et al. 2018).

The 2015 MSE suggested linking harvest strategy settings to the productivity of the species (Smith et al. 2015). For western jack mackerel, it was suggested that tier 1 harvest rates should be set at 12 per cent, that tier 2 harvest rates should be set at 50 per cent of tier 1, and that neither should be applied for longer than five years. Because information on life history and productivity for western jack mackerel is limited, data from eastern jack mackerel were used in the MSE instead, which may compromise the model outputs for the stock. A tier 1 harvest rate of 12 per cent was formally adopted in the 2017 SPF harvest strategy.

When the 2017–18 RBC was set, results from the DEPM survey were not available. Instead, tier 3 of the 2017 harvest strategy and the biomass estimate from Atlantis modelling (62,000 t) were used to recommend an RBC of 930 t.

Stock status determination

The peak harvest from this fishery (2016–17) was 2.2 per cent of the 2018 biomass estimate and 1.1 per cent of the biomass estimated using the Atlantis-SPF model. Catches have remained a low proportion of estimated biomass in the years catches were taken. This level of fishing mortality is unlikely to have substantially reduced spawning biomass. As a result, western jack mackerel is classified as not overfished. No catch was taken in the Commonwealth fishery in 2017–18. The stock is therefore classified as not subject to overfishing.

Redbait, east (Emmelichthys nitidus)

Redbait, east (Emmelichthys nitidus)

Line drawing: FAO

Stock structure

The stock structure of redbait in Australia has not been studied. Redbait within the SPF is assessed and managed as separate stocks in the eastern and western subareas (Figure 7.1).

Catch history

The redbait fishery started in the early 1980s. Total landings (Commonwealth and state) were less than 2,000 t per year between 1984–85 and 2000–01, but increased in 2001–02 and subsequent years, peaking at 7,450 t in 2003–04. Annual catches decreased steadily thereafter. The Commonwealth catch was 10 t in 2017–18 (Figure 7.7). State catches have been negligible since 2010–11.

Figure 7.7 Commonwealth eastern redbait catch and TAC, 2003–04 to 2017–18
Note: TAC Total allowable catch.
Stock assessment

The most recent DEPM surveys for eastern redbait—in 2005 and 2006 (Neira et al. 2008)—provided spawning biomass estimates of 86,990 t (coefficient of variation [CV] 0.37) and 50,782 t (CV 0.19), respectively. The average of these two estimates (68,886 t) was used to generate an RBC of 3,444 t for 2017–18, using the tier 2 decision rule (AFMA 2017b). After factoring in state catches, the AFMA Commission agreed to a TAC of 3,410 t.

An MSE in 2015 suggested linking harvest strategy settings to the productivity of the species (Smith et al. 2015). For eastern redbait, it was suggested that tier 1 harvest rates should be set at 9 per cent, that tier 2 harvest rates should be set at 50 per cent of tier 1, and that neither should be applied for longer than five years. A tier 1 harvest rate of 10 per cent for a maximum of five years and a tier 2 harvest rate of 5 per cent for a maximum of 10 years were adopted by the AFMA Commission for eastern redbait. Given the age of the DEPM estimate, the tier 2 harvest control rule was used as the basis for the 2017–18 RBC.

Peak total (Commonwealth and state) catch in 2003–04 was 10 per cent of the estimated spawning biomass average. Catch has consistently declined each year since then. Commonwealth catch in 2017–18 was less than 1 per cent of the spawning biomass estimate, and less than 1 per cent of the RBC.

Stock status determination

The peak catch from this fishery was 10 per cent of the spawning biomass estimate. Catches since then have remained low as a proportion of estimated biomass. Although the biomass estimate is dated, this level of fishing mortality is unlikely to have substantially reduced spawning biomass. As a result, eastern redbait is classified as not overfished.Fishing mortality is low as a proportion of estimated biomass, and below the 2017–18 RBC. The stock is therefore classified as not subject to overfishing.

Purse seine
AFMA

Redbait, west (Emmelichthys nitidus)

Stock structure

See redbait (east).

Catch history

No catches of western redbait were reported before 2001–02. Commonwealth catches increased from 1,100 t in 2001–02 to a peak of 3,228 t in 2006–07, and decreased steadily thereafter, with no reported catch between 2010–11 and 2014–15. Commonwealth catches were taken again in 2015–16 (1,157 t) and 2016–17 (1,140 t), but no catch was reported in 2017–18 (Figure 7.8). State catches have been negligible.

Figure 7.8 Commonwealth western redbait catch and TAC, 2003–04 to 2017–18
Note: TAC Total allowable catch.
Stock assessment

An MSE in 2015 suggested linking harvest strategy settings to the productivity of each species (Smith et al. 2015). For western redbait, it was suggested that tier 1 harvest rates should be set at 10 per cent, that tier 2 harvest rates should be set at 50 per cent of tier 1, and that neither should be applied for longer than five years. A harvest rate of 10 per cent of the egg survey biomass estimate was formally adopted for tier 1 stocks in the 2017 SPF harvest strategy (AFMA 2017a), with tier 2 being half the tier 1 level and tier 3 being 1.25 per cent of the Atlantis-SPF ecosystem modelling.

No egg survey has been undertaken for western redbait. As a result, an RBC of 825 t was calculated based on the mean biomass estimate (66,000 t) from the Atlantis-SPF model. This RBC is a substantial decrease from the value generated by the previous harvest strategy (2,900 t), which applied up to and including the 2016–17 season. The spawning biomass of western redbait estimated by the Atlantis-SPF model is consistent with spawning biomass estimates for other similar stocks; however, there is little empirical evidence to corroborate the outputs of the modelling. State catches were deducted from the RBC to obtain the 2017–18 TAC of 820 t.

Stock status determination

Catches in 2015–16 and 2016–17 were slightly more than what is now considered an appropriate catch level under the Commonwealth harvest strategy policy, given the information available. However, these catches are not expected to have reduced the stock to below the limit reference point. The stock is therefore classified as not overfished. There was no catch of western redbait in 2017–18. The stock is therefore classified as not subject to overfishing.

7.3 Economic status

Key economic trends

The gross value of production (GVP) in the SPF was estimated to be $1.3 million in 2007–08 (2016–17 dollars). This was 65 per cent lower than the estimate for 2005–06 ($3.8 million in 2016–17 dollars), primarily as a result of a rapid decline in prices and production (Figure 7.9). In 2007–08, attributed management costs were about 57 per cent of GVP. This indicates that net economic returns (NER) were likely to have been low in that year, even before fishing costs are considered. The GVP has been confidential since 2007–08 because fewer than five vessels have operated in the fishery. The number of vessels remained steady at three in 2016–17. However, fishing effort declined, reflecting the exit from the fishery of a factory trawler during the 2016–17 season. A decrease in the level of catch, from 13,210 t in the 2015–16 financial year to 6,096 t in the 2016–17 financial year, suggests that GVP probably decreased, but is still above the five-year average to 2014–15.

Figure 7.9 Real GVP for the SPF, 2006–07 to 2016–17
Note: GVP Gross value of production.

Management arrangements

The fishery is managed largely with output controls, with TACs set for each target species. For the 2017–18 fishing season, 30 entities held statutory fishing rights. Of the combined TACs for small pelagic species that were available in 2016–17, 80 per cent were uncaught. However, the percentage of TACs uncaught increased by 8 percentage points in the 2017–18 fishing season, to 88 per cent. Increased latency in 2017–18 was largely the result of lower catches of eastern jack mackerel.

Performance against economic objective

A meaningful biomass target to provide maximum economic yield (MEY) is difficult to determine for the SPF because of the high interannual variability in biomass levels (Small Pelagic Fishery Management Plan 2009). The absence of an explicit economic target makes it difficult to determine how effectively the fishery’s harvest strategy is delivering maximum NER to the Australian community. Pascoe and Hillary (2016) suggest that, for fisheries that target schooling species where there is no relationship between catch-per-unit-effort and biomass, such as jack mackerel in the eastern subarea of the SPF, maximum sustainable yield could be used as a proxy reference target for MEY. It is apparent from the low volume of catch relative to the TAC that this fishery has not been achieving its MEY over recent years. The exit from the fishery of a factory trawler part way through the 2016–17 season resulted in higher quota latency compared with the previous season, indicating that economic performance of the fishery may have declined. Despite higher latency, changes in NER are uncertain because of the lack of information about changes in cost structures of the industry as a result of introduction of the factory trawler in the latter part of the 2014–15 financial year and its subsequent departure in 2016–17.

7.4 Environmental status

The management plan for the SPF was most recently accredited under part 13 of the Environment Protection and Biodiversity Conservation Act 1999 on 26 October 2015; this accreditation expires on 26 October 2018. Two conditions were placed on the accreditation: that, before fishing, midwater trawl vessels have mitigation devices in place for dolphins, seals and seabirds; and that new midwater trawl vessels carry one observer for the first 10 trips, with additional observers or monitoring to be implemented after scientific assessment. Minimum levels for observer coverage in the SPF are 10 per cent of days fished for purse-seine vessels and 20 per cent of days fished for midwater trawl vessels.

Recent research by CSIRO (Smith et al. 2015) found that depletion of the four main target species in the SPF (jack mackerel, redbait, blue mackerel and Australian sardine) has only minor impacts on other parts of the ecosystem. The research suggested that, unlike other areas that show higher levels of dependence on similar species, such as in Peru (Smith et al. 2011), the food web in southern and eastern Australia does not appear to be highly dependent on SPF target species, and none of the higher trophic–level predators, including tunas, seals and penguins, has a high dietary dependence on the species.

Separate ecological risk assessments have been done for the midwater trawl and purse-seine fishing methods used in the fishery. For purse seine, 235 species were assessed at level 2; of these, 108 were assessed as being at high risk (Daley et al. 2007), with 29 remaining at high risk after applying AFMA’s residual risk guidelines (AFMA 2010). The ecological risk management plan identifies 3 seal species and 26 whale and dolphin species as being at high risk in the SPF. For midwater trawl, 235 species were assessed at level 2, with 26 of these assessed as being at high risk (Daley et al. 2007). No finfish species were assessed as being at high risk from either purse-seine or midwater trawl operations. The Ecological Risk Assessment for the mid-water trawl sector of the SPF was updated during 2017–18 and is expected to be published in late 2018. The report by CSIRO applied a revised methodology for conducting ecological risk assessments for Commonwealth fisheries. The results of this assessment will be used to inform the management of bycatch in this fishery.

Interactions with marine mammals are a key environmental concern for the midwater trawl fishery. A study commissioned by AFMA (January 2005 – February 2006) to quantify the nature and extent of interactions, and to evaluate potential mitigation strategies, found that fur seals entered the net in more than 50 per cent of midwater trawl operations during the study. The observed mortality rate was 0.12 seals per shot, using bottom-opening seal excluder devices (Lyle & Willcox 2008). The study concluded that effective, upward-opening seal excluder devices are needed when this type of gear is used. No dolphin interactions were recorded during the study.

In response to these results, AFMA requires all midwater trawlers to have an AFMA-approved, upward-opening seal excluder device before starting to fish. The Commonwealth SPF industry purse-seine code of practice (SPF Industry 2008) requires fishers to avoid interactions with species, where possible; implement mitigation measures, where necessary; release all captured protected species alive and in good condition; and report all interactions with protected species.

In May 2017, AFMA implemented the Small Pelagic Fishery Dolphin Strategy. The strategy aims to minimise dolphin interactions in the trawl sector of the fishery by creating incentives for fishers to innovate and adopt best practice to minimise interactions. The strategy will be reviewed throughout 2018, with results expected to be available in late 2018.

AFMA publishes quarterly logbook reports of interactions with protected species on its website. Six interactions with protected species were reported in the SPF during the 2017 calendar year: four were with bottlenose dolphins (Tursiops truncatus), which were dead;one was with an unidentified seal, which was dead; and one was with an Australian fur seal (Arctocephalus pusillus), which was dead.

7.5 References

AFMA 2010, Residual Risk Assessment of the level 2 ecological risk assessment species results report for the Small Pelagic Fishery—purse seine, Australian Fisheries Management Authority, Canberra.

—— 2014, Small Pelagic Fishery Harvest Strategy, June 2008, last revised April 2013, AFMA, Canberra.

—— 2015a, Small Pelagic Fishery Harvest Strategy, June 2008, last revised April 2015, AFMA, Canberra.

—— 2015b, ‘Small Pelagic Fishery Resource Assessment Group (SPFRAG) 20, minutes, 12 February 2015,’ AFMA, Canberra.

—— 2016a, ‘Small Pelagic Fishery Scientific Panel: meeting no. 1 minutes. 14 December 2015’, AFMA, Canberra.

—— 2016b, ‘Small Pelagic Fishery Scientific Panel: meeting no. 5 minutes. 15/16 December 2016’, AFMA, Canberra.

—— 2017a, Small Pelagic Fishery Harvest Strategy, June 2008, last revised April 2017, AFMA, Canberra.

—— 2017b, ‘Small Pelagic Fishery Scientific Panel (the Panel): meeting 6, minutes, 8 February 2017’, AFMA, Canberra.

—— 2017c, ‘Small Pelagic Fishery Scientific Panel (the Panel): meeting 8, minutes, 16 and 17 November 2017’, AFMA, Canberra.

Daley, R, Dowdney, J, Bulman, C, Sporcic, M, Fuller, M, Ling, S, Milton, D & Hobday, A 2007, Ecological risk assessment (ERA) for effects of fishing, Small Pelagic Fishery, AFMA, Canberra.

Dixon, PI, Worland, LJ & Chan, BHY 1993, Stock identification and discrimination of pilchards in Australian waters, using genetic criteria, Centre for Marine Studies, University of New South Wales, Sydney.

Izzo, C, Gillanders, BM & Ward, TM 2012, Movement patterns and stock structure of Australian sardine (Sardinops sagax) off South Australia and the east coast: implications for future stock assessment and management, final report, Fisheries Research and Development Corporation project 2009/021, South Australian Research and Development Institute publication F2011/000487-1, Research Report Series 611, SARDI Aquatic Sciences, Adelaide.

——, Ward, T, Ivey, A, Suthers, I, Stewart, J, Sexton, S & Gillanders, B 2017, ‘Integrated approach to determining stock structure: implications for fisheries management of sardine, Sardinops sagax, in Australian waters’, Reviews in Fish Biology and Fisheries, vol. 27, pp. 267–84.

Kailola, PJ, Williams, MJ, Stewart, PC, Reichelt, RE, McNee, A & Grieve, C 1993, Australian fisheries resources,Bureau of Rural Sciences & FRDC, Canberra.

Lyle, JM & Willcox, ST 2008, Dolphin and seal interactions with mid-water trawling in the Small Pelagic Fishery, including an assessment of bycatch mitigation strategies, Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, Hobart.

Neira, FI, Lyle, JM, Ewing, GP, Keane, JP & Tracey, SR 2008, Evaluation of egg production as a method of estimating spawning biomass of redbait off the east coast of Tasmania, final report, FRDC project 2004/039, TAFI, Hobart.

Pascoe, S & Hillary, R 2016, Bioeconomic target reference points for the Commonwealth Small Pelagics Fishery, report to AFMA, CSIRO, Hobart.

Punt, AE, Little, R & Hillary, R 2016, Updated management strategy evaluation for eastern jack and blue mackerel, report for AFMA, CSIRO Oceans and Atmosphere Flagship, Hobart.

Richardson, BJ 1982, ‘Geographical distribution of electrophoretically detected protein variation in Australian commercial fishes. I. Jack mackerel (Trachurus declivis [Jenyns])’, Australian Journal of Marine and Freshwater Research,vol. 33, pp. 917–26.

Schmarr, DW, Whittington, ID, Ovenden, JR & Ward, TM 2007, ‘Techniques for discriminating stocks of blue mackerel Scomber australasicus’, in TM Ward & PJ Rogers (eds), Development and evaluation of egg-based stock assessment methods for blue mackerel Scomber australasicus in southern Australia,final report, FRDC project 2002/061, SARDI Aquatic Sciences, Adelaide, pp. 53–83.

Smith, A, Brown, C, Bulman, C, Fulton, E, Johnson, P, Kaplan, I, Lozano-Montes, H, Mackinson, S, Marzloff, M, Shannon, L, Shin, Y & Tam, J 2011, ‘Impacts of fishing low-trophic level species on marine ecosystems’, Science,vol. 333, pp. 1147–50.

——, Ward, T, Hurtado, F, Klaer, N, Fulton, E & Punt, A 2015, Review and update of harvest strategy settings for the Commonwealth Small Pelagic Fishery: single species and ecosystem considerations,report for FRDC project 2013/028, CSIRO Oceans and Atmosphere Flagship, Hobart.

Smolenski, A, Ovenden, J & White, R 1994, ‘Preliminary investigation of mitochondrial DNA variation in jack mackerel (Trachurus declivis,Carangidae) from south-eastern Australian waters’, Australian Journal of Marine and Freshwater Research,vol. 45, pp. 495–505.

SPF Industry 2008, Commonwealth Small Pelagic Fishery voluntary code of practice, AFMA, Canberra.

Ward, TM & Rogers, PJ 2007, Evaluating the application of egg-based stock assessment methods for blue mackerel, Scomber australasicus, in southern Australia,final report to FRDC, Canberra.

——, Schmarr, DW, McLeay, DW, Rogers, L & Ivey, A 2007, A preliminary investigation of the spawning biomass of sardine (pilchard, Sardinops sagax) off eastern Australia, final report for New South Wales Department of Primary Industry, SARDI Aquatic Sciences, Adelaide.

——, Lyle, J, Keane, JP, Begg, G, Hobsbawn, P, Ivey, AR, Sakabe, R & Steer, MA 2011, Commonwealth Small Pelagic Fishery: status report 2010,report to AFMA, Canberra.

——, Burnell, O, Ivey, A, Carroll, J, Keane, J, Lyle, J & Sexton, S 2015a, Summer spawning patterns and preliminary daily egg production method survey of jack mackerel and Australian sardine off the east coast,final report, FRDC project 2013/053, SARDI Aquatic Sciences, Adelaide.

——, Grammer, G, Ivey, A, Carroll, J, Keane, J, Stewart, J & Litherland, L 2015b, Egg distribution, reproductive parameters and spawning biomass of blue mackerel, Australian sardine and tailor off the east coast during late winter and early spring, FRDC project 2014/033, FRDC & SARDI, West Beach.

——, Grammer, GL, Ivey, AR, Smart, JJ & Keane, JP 2018, Spawning biomass of jack mackerel (Trachurus declivis) and sardine (Sardinops sagax) between western Kangaroo Island, South Australia and south-western Tasmania, report to AFMA, SARDI publication F2018/000174-1, Research Report Series 983, SARDI Aquatic Sciences, Adelaide.

Whittington, ID, Ovenden, JR & Ward, TM 2012, ‘Discriminating stocks of blue mackerel using a holistic approach: a pilot study’, in JR McKenzie, B Parsons, AC Seitz, R Keller Kopf, M Mesa & Q Phelps (eds), Advances in fish tagging and marking technology,American Fisheries Society Symposium 76, pp. 397–417.

Yardin, MR, Dixon, PI, Coyle, T, Syahailatua, A & Avramidis, M 1998, ‘Stock discrimination of Sardinops sagax in south-eastern Australia’, in TM Ward, M Kinloch, GK Jones & FJ Neira (eds), A collaborative investigation of the usage and stock assessment of baitfish 76 in southern and eastern Australia with special reference to pilchards (Sardinops sagax), FRDC report 1994/024, FRDC, Canberra, pp. 85–174.

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Last reviewed:
22 Oct 2018