Western Tuna and Billfish Fishery

Chapter 24: Western Tuna and Billfish Fishery

A Williams, H Patterson and D Mobsby

FIGURE 24.1 Area fished in the Western Tuna and Billfish Fishery, 2018

TABLE 24.1 Status of the Western Tuna and Billfish Fishery
Status20172018Comments
Biological status a Fishing mortality BiomassFishing mortalityBiomass
Striped marlin (Kajikia audax)Subject to overfishingUncertainSubject to overfishingOverfished

Most recent estimates of biomass (2018) indicate the stock is below the default Commonwealth limit reference point. Current fishing mortality rate exceeds that required to produce MSY.

Swordfish
(Xiphias gladius)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfished

Most recent estimate of spawning biomass (2017) is above the default Commonwealth limit reference point. Current fishing mortality rate is below that required to produce MSY.

Albacore
(Thunnus alalunga)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfished

Most recent estimate of spawning biomass (2016) is above the default Commonwealth limit reference point. Current fishing mortality rate is below that required to produce MSY.

Bigeye tuna
(Thunnus obesus)
Not subject to overfishingNot overfishedNot subject to overfishingNot overfished

Most recent estimate of spawning biomass (2016) is above the default Commonwealth limit reference point. Current fishing mortality rate is below that required to produce MSY.

Yellowfin tuna
(Thunnus albacares)
Subject to overfishingNot overfishedSubject to overfishingNot overfished

Most recent estimate of spawning biomass (2018) is above the default Commonwealth limit reference point. Current fishing mortality rate is above that required to produce MSY.

Economic statusParticipation rate was low and latency remained high in 2018, suggesting little economic incentives to fish and relatively small net economic returns.

a Ocean-wide assessments and the default limit reference points from the Commonwealth Fisheries Harvest Strategy Policy (Department of Agriculture and Water Resources 2018) are used as the basis for status determination.
Notes: MSY Maximum sustainable yield. NER Net economic returns. TACC Total allowable commercial catch.

[expand all]

24.1 Description of the fishery

Area fished

The Western Tuna and Billfish Fishery (WTBF) operates in Australia’s Exclusive Economic Zone and high seas of the Indian Ocean (Figure 24.1). In recent years, fishing effort has concentrated off south-west Western Australia, with occasional activity off South Australia. Domestic management arrangements for the WTBF reflect Australia’s commitment to the Indian Ocean Tuna Commission (IOTC; see Chapter 20).

Fishing methods and key species

Key species in the WTBF are bigeye tuna (Thunnus obesus), yellowfin tuna (T. albacares), striped marlin (Kajikia audax) and swordfish (Xiphias gladius). Some albacore (Thunnus alalunga) is also taken. The main fishing gear in the WTBF is pelagic longline, with low levels of minor-line fishing (Table 24.2).

TABLE 24.2 Main features and statistics for the WTBF

Fishery statistics a

2017

2018

Stock

TACC
(t)

Catch
(t)

GVP
(2016–17)

TACC
(t)

Catch
(t)

GVP
(2017–18)

Striped marlin

125

1

Confidential

125

1

Confidential

Swordfish

3,000

166

Confidential

3,000

174

Confidential

Albacore

16

Confidential

12

Confidential

Bigeye tuna

2,000

67

Confidential

2,000

49

Confidential

Yellowfin tuna

5,000

72

Confidential

5,000

42

Confidential

Total

10,125

322

Confidential

10,125

278

Confidential

Fishery-level statistics

Effort

Pelagic longline: 417,997 hooks
Minor line: na

Pelagic longline: 404,880 hooks
Minor line: na

Fishing permits

95 boat SFRs

94 boat SFRs

Active vessels

Pelagic longline: 3
Minor line: 1

Pelagic longline: 2
Minor line: 1

Observer coverage

11.7% b

13.0% b

Fishing methods

Pelagic longline (monofilament mainline), minor line (handline, rod and reel, troll and poling), purse seine

Primary landing ports

Fremantle and Geraldton (Western Australia)

Management methods

Input controls: limited entry, gear and area restrictions

Output controls: TACCs, ITQs, byproduct restrictions

Primary markets

International: Japan, United States—fresh, frozen

Domestic: fresh, frozen

Management plan

Western Tuna and Billfish Management Plan 2005 (amended 2016); SFRs issued 2010

a Fishery statistics are provided by calendar year to align with international reporting requirements. Value statistics are by financial year. b From 1 July 2015, e-monitoring became mandatory for all full-time pelagic longline vessels in the WTBF. At least 10% of video footage of all hauls is reviewed to verify the accuracy of logbooks, which are required to be completed for 100% of shots.
Notes: GVP Gross value of production. ITQ Individual transferable quota. na Not available. SFR Statutory fishing right. TACC Total allowable commercial catch. – Not applicable.

Management methods

The management plan for the fishery began in 2005, although the Australian Fisheries Management Authority (AFMA) first granted statutory fishing rights in 2010. Under the management plan, output controls have been implemented in the fishery through individual transferable quotas (ITQs) for the four key commercial species (excluding striped marlin) (Table 24.2). Determinations of total allowable commercial catch (TACC) are made in accordance with Australia’s domestic policies, and apply to the Australian Fishing Zone and the high-seas area of the IOTC area of competence. A harvest strategy framework has been developed for the WTBF (Davies et al. 2008), with the intention that it be implemented if fishing effort increases in the fishery and sufficient data are available for use in the strategy. The framework includes a decision tree that defines rules and subsequent adjustments to the recommended biological catch (or level of fishing mortality) in response to standardised size-based catch rates.

The default limit reference points in the Commonwealth Fisheries Harvest Strategy Policy (Department of Agriculture and Water Resources 2018) are used to determine stock status in the WTBF. The limit reference point for biomass is 20% of the unfished biomass (0.2B0). For fishing mortality, the limit reference point is the fishing mortality that would achieve maximum sustainable yield (FMSY). The IOTC determines stock status relative to target reference points, not limit reference points, resulting in a different stock status reported by the IOTC for some stocks.

Electronic monitoring (e-monitoring) became mandatory for all full-time pelagic longline vessels in the Eastern Tuna and Billfish Fishery and the WTBF from 1 July 2015. At least 10% of video footage of all longline sets is reviewed to verify the accuracy of logbooks, which are required to be completed for 100% of sets.

Fishing effort

Effort in the WTBF was relatively low (<20 vessels) from the mid 1980s to the mid 1990s (Figure 24.2). Effort increased in the late 1990s, peaking at 50 active vessels in 2000, but then declined rapidly. Since 2005, fewer than five vessels have been active in the fishery each year.

FIGURE 24.2 Longline fishing effort, boat statutory fishing rights and active vessels in the WTBF, 1986–2018

Note: SFR Statutory fishing right.
Source: AFMA

Catch

Swordfish is the main target species in the WTBF, with annual catches peaking at more than 2,000 t in 2001 (Figure 24.3) and declining to a few hundred tonnes in recent years. Bigeye and yellowfin tuna are also valuable target species, although catches of these species have never been as high as for swordfish and have been more variable.

FIGURE 24.3 Total annual catch, by species, in the WTBF, 1986–2018

Source: AFMA

24.2 Biological status

Striped marlin (Kajikia audax)

Striped marlin (Kajikia audax)

Line drawing: FAO

Stock structure

Mamoozadeh, McDowell & Graves (2018) evaluated genetic variation in striped marlin populations sampled from the eastern and western Indian Ocean, and across the Pacific Ocean. Their results suggest that there could be genetically distinct east and west stocks of striped marlin in the Indian Ocean. However, the sample size from the eastern Indian ocean was small (eight fish), and no samples were collected from the central Indian Ocean, making it difficult to delineate a border between potential stocks. Therefore, striped marlin is currently considered to be a single distinct biological stock for assessments in the Indian Ocean.

Catch history

Catches of striped marlin in the WTBF have been relatively low (<50 t) since the mid 1980s and very low (<5 t) since 2000, with less than 1 t taken in 2018 (Figure 24.4). Total international catches in the IOTC area of competence declined from around 6,000 t in 1995 to around 2,000 t in 2009 (Figure 24.5). Annual catches increased from 2009, but declined in 2017 to 3,082 t, which is below the estimated MSY (4,730 t).

FIGURE 24.4 Striped marlin catch and TACC in the WTBF, 1983–2018

Note: TACC Total allowable commercial catch; initial TACC for 19 months.
Source: AFMA

FIGURE 24.5 Striped marlin catch in the IOTC area, 1970–2017

Source: IOTC

Stock assessment

A new stock assessment in 2018 used two assessment models: JABBA, a Bayesian state-space production model, and Stock Synthesis 3 (SS3) (IOTC 2018). The 2017 spawning biomass for the Indian Ocean–wide stock was estimated to be 13% of unfished (1950) biomass (SS3: SB2017/SB1950 = 0.13; range 0.09–0.14) and below the level that supports MSY (JABBA: SB2017/SBMSY = 0.33; no range available) (IOTC 2018). Fishing mortality was estimated to be above FMSY (JABBA: F2017/FMSY = 1.99; 95% confidence interval [CI] 1.21–3.62). Retrospective analysis for both the JABBA and SS3 models produced consistent stock status estimates, thus providing a degree of confidence in the predictive capabilities of the assessments.

Stock status determination

Both models indicate that the stock has been heavily depleted and is below the Commonwealth’s biomass limit reference point (0.2B0). The stock is therefore classified as overfished. Fishing mortality was estimated to be well above FMSY, so the stock is classified as subject to overfishing.

Swordfish (Xiphias gladius)

Swordfish (Xiphias gladius)

Line drawing: Gavin Ryan

Stock structure

Swordfish in the Indian Ocean is considered to be a single distinct biological stock. The possibility of a separate south-west Indian Ocean stock was examined in the Indian Ocean Swordfish Stock Structure project—a genetic study focused on the links between the south-west and other regions (Muths et al. 2013). The study found that genetic markers were consistent with a single stock in the Indian Ocean.

Catch history

Annual swordfish catch in the WTBF peaked at around 2,000 t in the early 2000s but has declined to below 350 t since 2005. In 2018, the annual catch was 174 t, a slight increase from 2017 (Figure 24.6). Total international catches of swordfish in the IOTC area of competence peaked in 2004 at more than 40,000 t, but declined to around 22,000 t in 2011 (Figure 24.7), likely as a result of the effects of piracy in the western Indian Ocean. Annual catches in the IOTC area of competence have increased since 2011, reaching 34,782 t in 2017, which is above the 2017 estimate of MSY (31,590 t).

FIGURE 24.6 Swordfish catch and TACC in the WTBF, 1983–2018

Note: TACC Total allowable commercial catch; initial TACC for 19 months.
Source: AFMA

FIGURE 24.7 Swordfish catch in the IOTC area, 1970–2017

Source: IOTC

Stock assessment

In 2017, the Indian Ocean swordfish assessment was updated using SS3 with data up to 2015 (IOTC 2017). The SS3 model was spatially disaggregated, sex explicit and age structured. The 2015 spawning biomass for the Indian Ocean–wide stock was estimated to be 31% of unfished (1950) biomass (SB2015/SB1950 = 0.31; range 0.26–0.43) and above the level that supports MSY (SB2015/SBMSY = 1.50; 80% CI 1.05–2.45) (IOTC 2017). Fishing mortality was estimated to be below FMSY (F2015/FMSY = 0.76; 80% CI 0.41–1.04).

Stock status determination

Assessments of the ocean-wide stock indicate that swordfish biomass is above the Commonwealth’s biomass limit reference point (0.2B0) and that fishing mortality is below FMSY. As a result, the stock is classified as not overfished and not subject to overfishing.

Albacore (Thunnus alalunga)

Albacore (Thunnus alalunga)

Line drawing: FAO

Stock structure

The stock structure of albacore in the Indian Ocean is uncertain, but the species is assumed to be a single biological stock for assessments. A global genetics study of albacore found that the Atlantic Ocean and Indian Ocean populations were not genetically distinguishable, and found no evidence of genetic heterogeneity within the Indian Ocean (Montes et al. 2012). However, the study was based on relatively small sample sizes, and samples were not collected across the entire distribution of albacore in the Indian Ocean. Two distinct stocks of albacore occur in the Atlantic and Pacific oceans, associated with distinct northern and southern ocean gyres. There is no northern gyre in the Indian Ocean, supporting the assumption of a single Indian Ocean albacore stock (IOTC 2014).

Catch history

Historically, albacore catches in the WTBF have been low, peaking at 115 t in 1994 and again at 94 t in 2001 (Figure 24.8). Since 2004, annual catches have been below 30 t, and were approximately 12 t in 2018. Total international catches in the IOTC area of competence peaked at more than 43,000 t in 2010, and have fluctuated between 30,000 t and 41,000 t since 2011 (Figure 24.9). The average annual catch during the past five years (2013–2017) was approximately 36,000 t, which is lower than the 2016 estimate of MSY (38,800 t) (IOTC 2018).

FIGURE 24.8 Albacore catch in the WTBF, 1983–2018

Source: AFMA

FIGURE 24.9 Albacore catch in the IOTC area, 1970–2017

Source: IOTC

Stock assessment

In 2016, five assessment models were used to assess the Indian Ocean albacore stock: SS3, ASPIC, a statistical catch-at-age model (SCAA), a Bayesian state-space production model (BSPM) and a Bayesian biomass dynamic model (BBDM). The results from the SS3 model were used to determine the current status of albacore and provide management advice (IOTC 2018), although the results from all the models were generally consistent. Considerable uncertainty exists in the SS3 model results because of uncertainty in catch-per-unit-effort data and length composition data, and a lack of biological information for albacore stocks in the Indian Ocean (IOTC 2018).

The result of the SS3 model indicated that the current (2014) biomass was above the limit reference point (SB2014/SB1950 = 0.37; 80% CI 0.28–0.46) and above the level that supports MSY (SB2014/SBMSY = 1.80; 80% CI 1.38–2.23). Fishing mortality was estimated to be below the level that supports MSY (F2014/FMSY = 0.85; 80% CI 0.57–1.12) (IOTC 2018).

Stock status determination

The assessment indicates that the spawning biomass is above the Commonwealth’s biomass limit reference point (0.2B0), and so the stock is classified as not overfished. Fishing mortality in the IOTC area is below FMSY, and so the stock is classified as not subject to overfishing.

Bigeye tuna (Thunnus obesus)

Bigeye tuna (Thunnus obesus)

Line drawing: FAO

Stock structure

The stock structure of bigeye tuna in the Indian Ocean is uncertain, but the species is considered to be a single distinct biological stock for assessments. The assumption of a single stock is based on a genetic study (Chiang et al. 2008) that indicated no genetic differentiation within the Indian Ocean, and tagging studies that have demonstrated large-scale movements of bigeye tuna within the Indian Ocean (IOTC 2014).

Catch history

Annual catches of bigeye tuna in the WTBF varied widely between 1983 and 2004, with the highest catch of more than 900 t in 1987 and the lowest catch of less than 22 t in 1991 (Figure 24.10). Catches have been more stable since 2004, and have not exceeded 200 t; catches over the past three years are below 100 t. Total international catches in the IOTC area of competence have declined from a peak of more than 160,000 t in 1999 to less than 100,000 t in recent years (Figure 24.11). Bigeye catch was 90,050 t in 2017 and averaged 95,997 t over the past five years, both of which are below the 2016 MSY estimate of 104,000 t.

FIGURE 24.10 Bigeye tuna catch and TACC in the WTBF, 1983–2018

Note: TACC Total allowable commercial catch; initial TACC for 19 months.
Source: AFMA

FIGURE 24.11 Bigeye tuna catch in the IOTC area, 1970–2017

Source: IOTC

Stock assessment

Six assessment models were used to assess the Indian Ocean bigeye stock in 2016: SS3, ASPIC, SCAA, an Age Structured Assessment Program (ASAP), a BBDM and a BSPM (IOTC 2017). The SS3 assessment was used to provide management advice, and it captured uncertainty in the stock–recruitment relationship, as well as the influence of tagging data on the model outcomes. Current (2015) spawning stock biomass was estimated to be above the level that would produce MSY (SB2015/SBMSY = 1.29; 80% CI 1.07–1.51). Similarly, the assessment indicated that spawning biomass was above 20% of the initial unfished level (SB2015/SB0 = 0.38; 80% CI not available). Fishing mortality was below the level associated with MSY (F2015/FMSY = 0.76; 80% CI 0.49–1.03).

Stock status determination

The SS3 assessment indicates that bigeye tuna spawning stock biomass is above the Commonwealth’s biomass limit reference point (0.2B0). As a result, the Indian Ocean bigeye tuna stock is classified as not overfished.Since the current spawning biomass is above the level that would produce MSY, and fishing mortality is below FMSY, the stock is classified as not subject to overfishing.

Yellowfin tuna (Thunnus albacares)

Yellowfin tuna (Thunnus albacares)

Line drawing: FAO

Stock structure

The stock structure of yellowfin tuna in the Indian Ocean is uncertain, but the species is considered to be a single biological stock for assessments. There have been no ocean-wide genetic studies of yellowfin tuna in the Indian Ocean, but tagging studies have demonstrated large-scale movements of yellowfin tuna, which is consistent with the assumption of a single stock (Langley, Herrera & Million 2012).

Catch history

Historical catches of yellowfin tuna in the WTBF have varied widely, from peaks of around 800 t in 1984 and 1995 to less than 15 t in 1991 and 1992 (Figure 24.12). Since the early 2000s, declining effort in the WTBF has resulted in reduced catches of yellowfin tuna. Catches have not exceeded 100 t since 2004 (Figure 24.12). Total international catches in the IOTC area of competence (Figure 24.13) peaked at more than 500,000 t in 2004, then declined for several years (2007–2011) because of the effects of piracy in the north-west Indian Ocean. From 2012 to 2015, catches remained relatively stable at around 400,000 t. Catches increased to 421,910 t in 2016, which is close to the 2016 MSY estimate of 422,000 t, but declined to 409,567 t in 2017.

FIGURE 24.12 Yellowfin tuna catch and TACC in the WTBF, 1983–2018

Note: TACC Total allowable commercial catch; initial TACC for 19 months.
Source: AFMA

FIGURE 24.13 Yellowfin tuna catch in the IOTC area, 1970–2017

Source: IOTC

Stock assessment

In 2018, the 2016 yellowfin tuna assessment was updated using SS3 and incorporating catch data, size, frequency data, tagging data and longline catch-per-unit-effort series (IOTC 2018). The results were largely similar to previous assessments, and indicate that 2017 levels of fishing mortality were above the level that would achieve MSY (F2017/FMSY = 1.20; 80% CI 1.00–1.71). Current spawning biomass was estimated to be below the level associated with MSY (SB2017/SBMSY = 0.83; 80% CI 0.74–0.97) but above the Commonwealth’s biomass limit reference point (SB2017/SB0 = 0.30; 80% CI 0.27–0.33).

Stock status determination

The assessments indicate that fishing mortality is above the level associated with MSY. As a result, the yellowfin tuna stock is classified as subject to overfishing.The biomass is above the default limit reference point (0.2B0), and, as a result, the stock is classified as not overfished.

24.3 Economic status

Key economic trends

Economic surveys have not been conducted in the WTBF since 2001–02 because of the low level of fishing activity. During 2017 and 2018, 95 and 94 fishing permits were issued in the fishery, respectively. A small number of vessels were operational in the fishery in those years (Table 24.2): four vessels (three pelagic longline and one minor line) in the 2017 fishing season and three vessels (two pelagic longline and one minor line) in the 2018 season. Total effort in the fishery decreased from 417,997 hooks in 2017 to 404,880 hooks in 2018, but the average number of hooks per active vessel increased. Total catch for quota species fell 14% in 2018 to 278 t, reflecting that the significant declines in the volumes of bigeye tuna and yellowfin tuna catch more than offset an increase in swordfish catch (Table 24.2).

As in previous years, landed catch in the fishery was a small proportion of the TACC during 2018. This high level of latent quota (the extent to which the TACC is not fully caught) and a relatively low participation rate indicate that permit holders expect low profitability from operating in the fishery.

Management arrangements

Before 2010, the WTBF was managed solely under an input control regime in which entry was limited, and gear and operating areas were restricted. In 2010, output controls were introduced in the form of species-specific TACCs, allocated as ITQs. The effect of the move to ITQs has not been measured because of the low participation in the WTBF in recent years. In general, ITQs allow fishers to use input combinations that are more efficient, particularly after input controls are relaxed. The transferability of fishing rights between fishers can also allow more efficient allocation of fishing rights so that catch is taken by the most efficient operators in the fishery. However, the very low levels of catch relative to the TACC in the WTBF are unlikely to provide any incentive for such trade to occur, minimising any efficiency gains.

Performance against economic objective

Although a harvest strategy has not been implemented because of low levels of effort in the fishery, the current management arrangements are unlikely to be constraining fishers’ ability to operate profitably. The high levels of latency experienced in the fishery are more likely to arise from market factors that affect business input costs and international tuna prices. Furthermore, since the WTBF accesses a relatively small component of broader, internationally managed ocean-wide stocks, domestic management actions to control catch are likely to have limited impact on the biomass of these stocks and, therefore, on fishers’ ability to access the resource for profitable operations. Hence, the economic objective of maximising net economic returns is likely being met for the fishery, as constraints to further fishing appear to be market related rather than arising from management arrangements.

24.4 Environmental status

The WTBF has been granted continued export approval under the Environment Protection and Biodiversity Conservation Act 1999, expiring on 28 November 2019. Conditions of export approval include a requirement to develop and implement a harvest strategy in the WTBF. Because of the very low effort in the fishery, the harvest strategy has not been implemented.

AFMA’s ecological risk assessment examined 187 fish species in the WTBF (38 chondrichthyans and 149 teleosts), all of which were classified as being at low risk of potential overfishing, based on the level 3 Sustainability Assessment for Fishing Effects analysis (Zhou, Smith & Fuller 2009). Although no shark species were identified as high risk, an increase in effort could move some species to a higher-risk category. A priority action identified in the WTBF ecological risk management report is to monitor the catch of, and level of interaction with, sharks. Management of shark interactions in this fishery will be reviewed if the landed amount of any one shark species exceeds 50 t within a year (AFMA 2010). Trip limits on sharks apply, depending on species.

AFMA publishes quarterly logbook reports of interactions with protected species on its website. In 2018, 258 shortfin mako sharks (Isurus oxyrinchus) were hooked in the WTBF; 1 was dead, and 257 were released in an unknown condition. Five porbeagles (Lamna nasus) were also released in unknown condition. Twelve leatherback turtles (Dermochelys coriacea) were also hooked and released alive, as were 10 loggerhead turtles (Caretta caretta). Six olive ridley turtles (Lepidochelys olivacea) were hooked, with four alive and two dead. Three flesh-footed shearwaters (Ardenna carneipes) and one unidentified albatross were all dead after being hooked. Finally, two long-finned pilot whales (Globicephala melas) were hooked, with one released alive and one dead, and one Cuvier’s beaked whale (Ziphius cavirostris) was released alive.

24.5 References

AFMA 2010, Ecological risk management: report for the Western Tuna and Billfish Fishery, Australian Fisheries Management Authority, Canberra.

Chiang, H-C, Hsu, C-C, Wu, GC-C, Chang, S-K & Yang, H-Y 2008, ‘Population structure of bigeye tuna (Thunnus obesus) in the Indian Ocean inferred from mitochondrial DNA’, Fisheries Research, vol. 90, pp. 305–12.

Davies, C, Campbell, R, Prince, J, Dowling, N, Kolody, D, Basson, M, McLoughlin, K, Ward, P, Freeman, I & Bodsworth, A 2008, Development and preliminary testing of the harvest strategy framework for the Western Tuna and Billfish Fishery, CSIRO, Hobart.

Department of Agriculture and Water Resources 2018, Commonwealth Fisheries Harvest Strategy Policy, Department of Agriculture and Water Resources, Canberra.

IOTC 2014, Report of the seventeenth session of the Scientific Committee, Seychelles, 8–12 December 2014, IOTC-2014-SC-R[E], Indian Ocean Tuna Commission, Victoria, Seychelles.

—— 2017, Report of the twentieth session of the Scientific Committee, Seychelles, 30 November – 4 December 2017, IOTC-2017-SC-R[E], IOTC, Victoria, Seychelles.

—— 2018, Report of the twenty-first session of the Scientific Committee, Seychelles, 3–7 December 2018, IOTC-2018-SC-R[E], IOTC, Victoria, Seychelles.

Langley, A, Herrera, M & Million, J 2012, ‘Stock assessment of yellowfin tuna in the Indian Ocean using MULTIFAN-CL’, paper presented at the 14th session of the IOTC Working Party on Tropical Tunas, Mauritius, 24–29 October 2012, IOTC-2012-WTT14-38_Rev 1, IOTC, Victoria, Seychelles.

Mamoozadeh, NR, McDowell, JR & Graves, JE 2018, ‘Genetic population structure of striped marlin (Kajikia audax) in the Indian Ocean’, paper presented at the 16th session of the IOTC Working Party on Billfish, Cape Town, South Africa, 4–8 September 2018, IOTC-2018-WPB16-20, IOTC, Victoria, Seychelles.

Montes, I, Iriondo, M, Manzano, C, Arrizabalaga, H, Jiménez, E, Angel Pardo, M, Goni, N, Davies, CA & Estonba, A 2012, ‘Worldwide genetic structure of albacore Thunnus alalunga revealed by microsatellite DNA markers’, Marine Ecology Progress Series, vol. 471, pp. 183–91.

Muths, D, LeCouls, S, Evano, H, Grewe, P & Bourjea, J 2013, ‘Multi-genetic marker approach and spatio-temporal analysis suggest there is a single panmictic population of swordfish Xiphias gladius in the Indian Ocean’, PLoS One, vol. 8, e63558.

Zhou, S, Smith, T & Fuller, M 2009, Rapid quantitative risk assessment for fish species in major Commonwealth fisheries, report to AFMA, Canberra.

AFMA officer
Dylan Maskey, AFMA



Last reviewed: 4 November 2019
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