Small Pelagic Fishery

Chapter 7: Small Pelagic Fishery

N Marton and AH Steven

FIGURE 7.1 Area fished in the Small Pelagic Fishery, 2018–19

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

Table 7.1 Status of the Small Pelagic Fishery
 20172018Comments
Status Biological statusFishing
mortality
BiomassFishing
mortality
Biomass
Australian sardine
(Sardinops sagax)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfished

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, east
(Scomber
australasicus
)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfished

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 overfished

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.

Jack mackerel, east
(Trachurus declivis)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfished

Recent 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 overfished

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.

Redbait, east
(Emmelichthys nitidus)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfished

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.

Redbait, west
(Emmelichthys nitidus)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfished

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.

Economic statusEstimates of NER are not available for the SPF, although the high degree of latency in the fishery suggests that NER are likely low. An increase in the level of catch in 2017–18 suggests that gross value of production is likely to have increased in 2017–18. Trends 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 stock-level 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 exceptions are the western stocks of Australian sardine, which are managed by Western Australia, South Australia and Victoria.

Stocks in the SPF are managed under 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 2017b), which adopts a target reference point of 0.5B0 (50% 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 stock. 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-based biomass estimate. 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 as to how well the DEPM-based biomass estimate 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 subsequent reduction in exploitation rate. Stocks without a DEPM-based biomass estimate have biomass estimated using the Atlantis ecosystem model developed for the SPF. These have a further reduced exploitation rate but are still classified as tier 3. When setting the RBCs for the 2018–19 season, redbait (west) was the only SPF stock without a DEPM-based biomass estimate. A DEPM-based biomass estimate was finalised for redbait west in 2019 (based on surveys in late 2017) to support management in 2019–20. Consequently, the Atlantis-derived biomass estimate and associated exploitation rate are no longer used.

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 sardine20510552014
Blue mackerel, east1557.553.752015
Blue mackerel, west1557.553.752005
Jack mackerel, east12561032014
Jack mackerel, west12561032017
Redbait, east1055102.52006
Redbait, west b1055102.52017

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 up to the 2018-19 season because there is no DEPM biomass estimate. A DEPM biomass estimate has since been generated.
Note: DEPM Daily egg production method.

Biomass is difficult to estimate for small pelagic species that exhibit high interannual variability. Where DEPM-based biomass estimates are available, a key assumption for assessing small pelagic stocks is that these estimates are a reliable indicator of population size. However, outputs from DEPM surveys can have large confidence intervals (CIs). In this chapter, spawning biomass estimates are generally presented with the 95% CI of the range of possible estimates.

Fishing effort

Most historical fishing effort occurred off the east and west coasts of Tasmania. Effort in the SPF increased in 2014–15, 2015–16 and 2016–17 with the operation of a factory freezer trawler. This vessel has since left Australian waters (AFMA 2016), but a different midwater trawler entered the fishery in 2017.

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 SPF have reflected a lack of markets and processing facilities. The operation of a factory freezer trawler in the 2014–15, 2015–16 and 2016–17 fishing seasons led to increased catches, reaching a peak of around 12,000 t in 2015–16. After the factory freezer trawler left the fishery during the 2016–17 season (AFMA 2016), total catch decreased. Since then, catch has increased to over 9,000 t in 2018–19, due to increasing catches of eastern blue mackerel and eastern jack mackerel by a smaller vessel that entered the fishery in late 2017.

TABLE 7.3 Main features and statistics for the SPF

Fishery statistics a

2017–18 fishing season

2018–19 fishing season

Stock name

TAC
(t)

Catch
(t)

GVP

(2017–18)

TAC
(t)

Catch
(t)

Australian sardine

9,550

97

Confidential

9,510

132

Blue mackerel, east

12,090

2,858

Confidential

12,090

3,811

Blue mackerel, west

3,230

Confidential

3,230

Jack mackerel, east

18,880

2,748

Confidential

18,890

4,942

Jack mackerel, west

920

Confidential

4,190

Redbait, east

3,410

10

Confidential

3,420

539

Redbait, west

820

Confidential

820

Total fishery

48,900

5,713

Confidential

52,150

9,424

Fishery-level statistics

Effort

Purse seine: 152 search-hours
Midwater trawl: 223 shots

Purse seine: 208 search-hours
Midwater trawl: 216 shots

Fishing permits

29 entities held quota SFRs in 2017–18

31 entities held quota SFRs in 2018–19

Active vessels

Purse seine: 2
Midwater trawl: 1

Purse seine: 3
Midwater trawl: 1

Observer coverage

Purse seine: 0%
Midwater trawl: 36%

Purse seine: 21%
Midwater trawl: 18%

Fishing methods

Purse seine, midwater trawl

Primary landing ports

Iluka, Ulladulla (New South Wales)

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 – 30 April. Value statistics are by financial year and are not available for 2018–19.
Notes: GVP Gross value of production. ITQ Individual transferable quota. SFR Statutory fishing right. TAC Total allowable catch. – Not applicable.

7.2 Biological status

Australian sardine (Sardinops sagax)

Australian sardine (Sardinops sagax)

Line drawing: FAO

Stock structure

Several studies have 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 integrated assessment that included 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 in 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, before decreasing to 894 t in 2014–15—its lowest level since 2001–02. Total catch increased to 2,887 t in 2016–17, primarily driven by increased catches by the Victorian fleet. The total combined catch (state and Commonwealth, excluding Victorian catches because they were confidential) for 2017–18 was 427 t, comprising 97 t of Commonwealth catch and 330 t of state catch. Commonwealth catch for 2018–19 was 132 t (Figure 7.2); state catches are not yet available.

FIGURE 7.2 Commonwealth Australian sardine catch and TAC in the SPF, 2003–04 to 2018–19

Note: TAC Total allowable catch.

Stock assessment

Egg surveys for the east coast stock of Australian sardine (undertaken in association with eastern blue mackerel egg surveys) were last conducted in August–September 2014. Spawning biomass was estimated using the DEPM at 49,600 t (95% CI 24,200–213,300 t) (Ward et al. 2015a).

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 an RBC for 2017–18.

The 2015 MSE suggested linking harvest strategy settings to the productivity of the species (Smith et al. 2015). For Australian sardine, Smith et al. (2015) suggested that tier 1 harvest rates could be increased from 15% to 33%, that tier 2 harvest rates should be set at 50% of tier 1, and that neither should be applied for longer than five years. A tier 1 harvest rate of 20% was formally adopted in the 2017 SPF harvest strategy. This lower harvest rate reflects uncertainty in some of the life-history characteristics of the eastern Australian sardine stock and differences from the rate applied for the South Australian Sardine Fishery (25%) (AFMA 2015a). Also, adopting a 33% harvest rate would have been a considerable increase on the rate at the time (AFMA 2015a). 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.

Because of the age of the DEPM estimate, the 2018–19 season was treated as season three of five at tier 1, despite it only being the second season that tier 1 had been used. The tier 1 exploitation rate of 20% equates to an RBC of 9,915 t. After factoring in state catches, the Australian Fisheries Management Authority (AFMA) Commission agreed to a TAC of 9,510 t.

The most recent year that catch data for all states (including Victoria) and the Commonwealth are available is 2016–17, when the total catch was 2,887 t. This is below the RBC calculated using an MSE-tested harvest strategy. Commonwealth catch for 2017–18 and 2018–19 was also below the RBC.

Stock status determination

Recent catches have been below the RBC calculated using an MSE-tested harvest strategy and are a small proportion of the most recent estimate of biomass. This level of fishing mortality is unlikely to have substantially reduced spawning biomass. On this basis, the Australian sardine stock is classified as not overfished and 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 subdivisions. 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 began exceeding state catch in 2015–16 and continues to be higher. Total combined catch in 2017–18 was 3,119 t, comprising 2,858 t from the Commonwealth and 261 t from state fisheries. The highest reported catches were in 2018–19 when Commonwealth catch was 3,811 t (Figure 7.3). State catches for the season are not yet available.

FIGURE 7.3 Commonwealth eastern blue mackerel catch and TAC, 2003–04 to 2018–19

Note: TAC Total allowable catch.

Stock assessment

Egg surveys for the eastern stock of blue mackerel (and Australian sardine) were conducted in August–September 2014. For eastern blue mackerel, the DEPM-based estimate of spawning biomass was 83,300 t (95% CI 35,100–165,000 t) (Ward et al. 2015a). 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. (2015a) therefore suggest that their estimate of spawning biomass be treated with caution.

As for Australian sardine, although the 2014 DEPM-based biomass estimate was available for use for both the 2015–16 and 2016–17 seasons, results from the previous DEPM-based biomass 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 an RBC.

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% to 23%, that tier 2 harvest rates should be set at 50% 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. There was also some concern about 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% was formally retained in the 2017 SPF harvest strategy.

Because of the age of the DEPM-based biomass estimate, the 2018–19 season was treated as season three of five at tier 1, despite it only being the second season that tier 1 had been used. The tier 1 exploitation rate of 15% equates to an RBC of 12,495 t. After factoring in state catches, the AFMA Commission agreed to a TAC of 12,090 t.

The most recent year that both state and Commonwealth catch data are available is 2017–18, when the total catch was 3,119 t. This is below the RBC calculated using the MSE-tested harvest strategy. Commonwealth catch for 2018–19 was also below the RBC.

Stock status determination

Recent catches have been below the RBC calculated using an MSE-tested harvest strategy and are a small proportion of the most recent estimate of biomass (3.7% in 2017–18, including state catches, and 4.6% in 2018–19, which does not include state catches). This level of fishing mortality is unlikely to have substantially reduced spawning biomass. On this basis, the eastern blue mackerel stock is classified as not overfished and 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, peaked in 2008–09 at 2,164 t and decreased steadily thereafter. Catch was negligible between 2011–12 and 2014–15 in both the state and Commonwealth fisheries. No Commonwealth catch was reported in 2017–18 or 2018–19 (Figure 7.4), and state catches have been either negligible or confidential in recent years. State catches are not available for 2018–19.

FIGURE 7.4 Commonwealth western blue mackerel catch and TAC, 2003–04 to 2018–19

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% 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%, that tier 2 harvest rates should be set at 50% 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% for tier 1) in the 2017 SPF harvest strategy.

Tier 3 of the 2017 harvest strategy (a harvest rate of 50% of tier 2) was used to recommend a 2018–19 RBC of 3,243 t. This was the second 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.

The most recent year that both state and Commonwealth catch data are available is 2017–18, when the total catch was less than 1 t. This is below the RBC calculated using an MSE-tested harvest strategy. There was no Commonwealth catch in 2018–19.

Stock status determination

Recent catches have been below the RBC calculated using an MSE-tested harvest strategy and are a small proportion of the most recent estimate of biomass (peaking at approximately 4% in 2008–09). Although the 2005 biomass estimate is dated, the level of fishing mortality in any year is unlikely to have substantially reduced spawning biomass. On this basis, the western blue mackerel stock is classified as not overfished and not subject to overfishing.

Small pelagic purse-seine net
AFMA

Jack mackerel, east (Trachurus declivis)

Jack mackerel, east (Trachurus declivis)

Line drawing: FAO

Stock structure

The stock structure of jack mackerel is unclear. 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 2017d). 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 in 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. State catches have been negligible in recent years; however, Commonwealth catch has increased, reaching 6,316 t in 2015–16 before decreasing to 4,942 in 2018–19 (Figure 7.5). The total combined catch (state and Commonwealth) for 2017–18 was 2,751 t, comprising 2,748 t of Commonwealth catch and 3 t of state catch. Commonwealth catch for 2018–19 was 4,942 t (Figure 7.5). State catches are not yet available for 2018–19.

FIGURE 7.5 Commonwealth eastern jack mackerel catch and TAC, 2003–04 to 2018–19

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. 2015b), and a spawning biomass of 157,805 t (95% 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%, that tier 2 harvest rates should be set at 50% 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% was formally adopted in the 2017 SPF harvest strategy. The SPF Scientific Panel used the 2014 DEPM-based biomass estimate to recommend a 2018–19 RBC of 18,937 t, using tier 1 of the 2017 harvest strategy (AFMA 2017c). After factoring in state catches, the AFMA Commission agreed to a TAC of 18,890 t.

The most recent year that both state and Commonwealth catch data are available is 2017–18, when the total catch was 2,751 t. This is below the RBC calculated using an MSE-tested harvest strategy. Commonwealth catch in 2018–19 was also below the RBC.

Stock status determination

Recent catches have been below the RBC calculated using an MSE-tested harvest strategy and are a small proportion of the most recent estimate of biomass (peaking at 4% in 2015–16). This level of fishing mortality is unlikely to have substantially reduced spawning biomass. On this basis, the eastern jack mackerel stock is classified as not overfished and not subject to overfishing.

Jack mackerel, west (Trachurus declivis)

Stock structure

See jack mackerel, east.

Catch history

Total catch (state and Commonwealth) for western jack mackerel did not exceed 250 t before 2005–06. Commonwealth catch was zero or negligible from 2011–12 to 2014–15, and increased to 634 t in 2015–16 and 686 t in 2016–17. No Commonwealth catch was reported for 2017–18 or 2018–19 (Figure 7.6). State catches are not available for 2018–19 and have been confidential for the preceding three years.

FIGURE 7.6 Commonwealth western jack mackerel catch and TAC, 2003–04 to 2018–19

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 2017d) 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%, that tier 2 harvest rates should be set at 50% 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% was formally adopted in the 2017 SPF harvest strategy.

The SPF Scientific Panel recommended a 2018–19 RBC of 4,197 t, using the initial biomass estimate and tier 1 of the 2017 harvest strategy (AFMA 2017c). After factoring in state catches, the AFMA Commission agreed to a TAC of 4,190 t.

Stock status determination

In years when catches have been taken, they have been below the RBC calculated using an MSE-tested harvest strategy and are a small proportion of the most recent estimate of biomass (peaking at approximately 2.2% in 2016–17). This level of fishing mortality is unlikely to have substantially reduced spawning biomass. On this basis, the western jack mackerel stock is classified as not overfished and 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. Commonwealth catch for 2018–19 was 539 t (Figure 7.7). State catches have been negligible or confidential in recent years and are not available for 2018–19.

FIGURE 7.7 Commonwealth eastern redbait catch and TAC, 2003–04 to 2018–19

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 2018–19, using the tier 2 decision rule (AFMA 2017c). After factoring in state catches, the AFMA Commission agreed to a TAC of 3,420 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%, that tier 2 harvest rates should be set at 50% of tier 1, and that neither should be applied for longer than five years. A tier 1 harvest rate of 10% for a maximum of 5 years and a tier 2 harvest rate of 5% 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 2018–19 RBC.

Peak total (Commonwealth and state) catch in 2003–04 was 10% of the estimated spawning biomass average. Catch has consistently declined each year since then. Commonwealth catch in 2018–19 was less than 1% of the spawning biomass estimate, and 16% of the RBC.

Stock status determination

Recent catches have been below the RBC calculated using an MSE-tested harvest strategy and are a small proportion of the most recent estimate of biomass (8% in 2018–19). This level of fishing mortality is unlikely to have substantially reduced spawning biomass. On this basis, the redbait east stock is classified as not overfished and not subject to overfishing.

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 or 2018–19 (Figure 7.8). No state catches have been reported in recent years.

FIGURE 7.8 Commonwealth western redbait catch and TAC, 2003–04 to 2018–19

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%, that tier 2 harvest rates should be set at 50% of tier 1, and that neither should be applied for longer than five years. A harvest rate of 10% of the egg survey biomass estimate was formally adopted for tier 1 stocks in the 2017 SPF harvest strategy (AFMA 2017b), with tier 2 being half the tier 1 level and tier 3 being 1.25% of the Atlantis-SPF ecosystem modelling.

An RBC of 825 t was calculated based on the mean biomass estimate (66,000 t) from the Atlantis-SPF model in 2015 (Fulton 2015). State catches were deducted from the RBC to obtain the 2018–19 TAC of 820 t. 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, at the time there was little empirical evidence to corroborate the outputs of the modelling.

Biomass has since been estimated using the DEPM (Ward et al. 2019). The DEPM-based biomass was estimated at 66,787 t (95% CI 28,797–190,392 t). The RBC generated from these analyses was 6,678 t (AFMA 2018).

Stock status determination

Recent catches have been below the RBC calculated using an MSE-tested harvest strategy and are not expected to have reduced the stock to below the limit reference point. The stock is therefore classified as not overfished. No catch of western redbait was recorded in 2018–19. 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% 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. In 2007–08, attributed management costs were about 57% 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 2017–18. A decrease in the level of catch, from 13,210 t in the 2015–16 financial year, when a factory freezer trawler operated in the fishery, to 8,150 t in the 2017–18 financial year, suggests that GVP probably decreased, but this catch level is well above the five-year average to 2014–15.

Management arrangements

The fishery is managed largely with output controls, with TACs set for each stock. For the 2018–19 fishing season, 31 entities held statutory fishing rights. Of the combined TACs for small pelagic stocks that were available in 2017–18, 82% were uncaught.

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 (AFMA 2017b). However, economic targets have been estimated for the key species caught in the fishery in Pascoe and Hillary (2016) and Smith et al. (2015). These studies suggest that MEY for the key species caught can approximate maximum sustainable yield (MSY) under certain assumptions and range from around B30 to B36 for the target species (Smith et al. 2015). Given the uncertainty in these estimates, the Harvest Strategy Policy (HSP) proxy of 1.2BMSY is applied, with an additional level of precaution, recognising that small pelagic fish have some level of ecological function in the ecosystem. This results in targets of B50 for target species, slightly above the default B48 target given in the HSP.

The exit from the fishery of a factory freezer trawler part-way through the 2016–17 season resulted in higher quota latency than in the previous season, indicating that economic performance of the fishery may have declined. Some of this latency has dissipated with the subsequent entry of a new vessel to the fishery following the departure of the factory trawler. Trends in NER are uncertain because of the lack of information about changes in cost structures of the industry as a result of structural change in the fishing fleet in recent years. The high level of latency in the fishery suggests that NER are low.

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 21 October 2018; this accreditation expires on 21 October 2023. 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% of days fished for purse-seine vessels and 20% 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, 185 species were assessed at level 1; none were deemed high risk, so none progressed to level 2, mainly because of limited historical and current fishing activity (Bulman et al. 2017). 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 to 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% 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 purse-seine code of practice for the SPF (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 (AFMA 2017a). 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 was reviewed in 2018–19, with an updated strategy due to be released in the third quarter of 2019.

AFMA publishes quarterly logbook reports of interactions with protected species on its website. Thirty-three interactions with protected species were reported in the SPF during 2018. These comprised 18 New Zealand fur seals (Arctocephalus forsteri; 3 alive and 15 dead); 5 Australian fur seals (A. pusillus; dead); 3 unidentified seals (dead); 3 common dolphins (Delphinus sp.); 2 shy albatross (Thalassarche cauta; alive); 1 unidentified albatross (alive); and 1 prion, petrel or shearwater (alive).

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 minute, 12 February 2015, AFMA, Canberra.

—— 2016, ‘Small Pelagic Fishery Scientific Panel meeting 1, minutes, 14 December 2015’, AFMA, Canberra.

—— 2017a, Small Pelagic Fishery dolphin strategy, AFMA, Canberra.

—— 2017b, Small Pelagic Fishery harvest strategy, June 2008, last revised April 2017, AFMA, Canberra.

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

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

—— 2018, ‘Small Pelagic Fishery Scientific Panel (the Panel) meeting 10, minutes, 26 November 2018’, AFMA, Canberra.

Bulman, C, Sporcic, M, Fuller, M & Hobday, A 2017, Ecological risk assessment for effects of fishing: report for the midwater trawl sub-fishery of the Small Pelagic Fishery, CSIRO, Hobart.

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.

Fulton, EA 2015, Stocks sizes of Small Pelagic Fishery species in Atlantis-SPF, CSIRO, Hobart.

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.

——, Grammer, G, Ivey, A, Carroll, J, Keane, J, Stewart, J & Litherland, L 2015a, 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 Aquatic Sciences, Adelaide.

——, Burnell, O, Ivey, A, Carroll, J, Keane, J, Lyle, J & Sexton, S 2015b, 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, 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.

——, Grammer, GL, Ivey, AR, & Keane, JP 2019, Spawning biomass of redbait (Emmelichthys nitidus) between western Kangaroo Island, South Australia and south-western Tasmania in October 2017, report to AFMA, SARDI publication F2019/000053-1, Research Report Series 1011, 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.




Last reviewed: 4 November 2019
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