Chapter 26: Macquarie Island Toothfish Fishery
H Patterson and K Mazur
TABLE 26.1 Status of the Macquarie Island Toothfish Fishery
|Biological status|| Fishing mortality|| Biomass||Fishing mortality||Biomass|| |
|Patagonian toothfish (Dissostichus eleginoides)||Not subject to overfishing||Not overfished||Not subject to overfishing||Not overfished||TACs are set in accordance with a precautionary harvest strategy. Most recent estimate of biomass is above the limit reference point.|
|Economic status||Estimates of NER are not available but are likely positive for the 2016–17 and 2017–18 fishing seasons because the TAC latency for Patagonian toothfish was low for both seasons. NER in the 2017–18 fishing season are likely to be lower than in the previous season because loss of gear and difficult operating conditions increased fishing costs. Higher quota latency and a lower catch per longline day compared with the previous season also indicate lower NER.|
NER Net economic returns.
TAC Total allowable catch.
26.1 Description of the fishery
Macquarie Island is a subantarctic island about 1,500 km south of Tasmania (Figure 26.1). The island is a nature reserve in the Tasmanian reserve system and is included on the World Heritage List (UNESCO 1998). The waters within 3 nautical miles (nm) of the island are under Tasmanian jurisdiction, while waters between 3 nm and the 200 nm outer boundary of the Australian Fishing Zone are managed by the Australian Government. The south-eastern quadrant of the Macquarie Island region out to 200 nm is a marine reserve (Figure 26.1). The Macquarie Island Toothfish Fishery (MITF) is outside the area covered by the Convention on the Conservation of Antarctic Marine Living Resources; however, the ecosystem-based management approach used by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has been adopted for the fishery, including comprehensive observer coverage and precautionary harvest control rules.
Fishing methods and key species
Historically, trawling was the main fishing method used in the MITF. In 2011, longlining was added as an approved fishing method (AFMA 2010). This followed a longlining trial over four seasons (2007–2010) that demonstrated longlining as an effective method for targeting Patagonian toothfish (Dissostichus eleginoides)and showed that mitigation methods could be implemented to minimise seabird interactions with longline gear (AFMA 2010). Since the 2010–11 season, toothfish in the MITF have been solely taken using longline, with the exception of a trial of pots in the 2013–14 fishing season. Bycatch is generally low and is regulated by a 50 t limit for any one species. The bycatch, primarily grenadier (Macrourus spp.)and violet cod (Antimora rostrata), has never exceeded the 50 t limit for any one species in a season.
The harvest strategy for Patagonian toothfish is consistent with the precautionary approach of the CCAMLR and is considered more precautionary than the guidelines of the Commonwealth Fisheries Harvest Strategy Policy (HSP; DAFF 2007). For Patagonian toothfish, the reference points dictate that median escapement of the spawning biomass at the end of a 35-year projection period is 50 per cent of median pre-exploitation level and that the probability of the spawning biomass dropping below 20 per cent of its pre-exploitation median level is less than 10 per cent over the projection. The total allowable catch (TAC) was previously set separately for the two main areas (Aurora Trough and Macquarie Ridge). However, based on scientific advice that it is highly likely that there is a single stock of Patagonian toothfish around Macquarie Island (see ‘Stock structure’, below), the management plan was amended in January 2012 to merge the two areas, and a single TAC is now set for the entire fishery. The MITF was recertified as sustainable by the Marine Stewardship Council in July 2017.
The effort in the fishery has been consistent over time, with one or two vessels active in the fishery every year since the fishery began in 1994.
Table 26.2 Main features and statistics for the MITF
|Fishery statistics a||2016–17 fishing season||2017–18 fishing season|
|Real value (2015–16)||TAC|
|Real value (2016–17)|
|Effort (longline days)||92||112|
|Fishing permits||2 quota SFR holders||2 quota SFR holders|
|Observer coverage b||100% vessel coverage||100% vessel coverage|
|Fishing methods||Demersal longline, demersal trawl|
|Primary landing ports||Devonport and Hobart (Tasmania); Nelson (New Zealand)|
|Management methods||Input controls: limited entry, gear restrictions, closures|
Output controls: TACs, ITQs
|Primary markets||International: United States, Japan—frozen|
|Management plan||Macquarie Island Toothfish Fishery Management Plan 2006 (amended 2012)|
a Fishery statistics are provided by fishing season, unless otherwise indicated. The 2017–18 fishing season was 15 April 2017 – 14 April 2018. Real-value statistics are provided by financial year.
b All vessels carry two observers on each trip.
ITQ Individual transferable quota.
SFR Statutory fishing right.
TAC Total allowable catch.
26.2 Biological status
Patagonian toothfish (Dissostichus eleginoides)
Line drawing: FAO
The Patagonian toothfish stock at Macquarie Island is considered to be distinct from other regional toothfish populations in the Southern Ocean (Appleyard, Ward & Williams 2002). Genetic studies (for example, Appleyard, Ward & Williams 2002) and toothfish tagging programs (for example, Williams et al. 2002) indicate that a single stock exists in the MITF area.
The catch of Patagonian toothfish in the MITF (Figure 26.2) has been variable over time and generally below, but close to, the TAC. Initial catches in the fishery were relatively high but decreased from 1999 to 2003, when the Aurora Trough was effectively closed to commercial fishing, and only a single vessel was permitted to fish to maintain the tagging program and conduct experimental acoustic surveys. Catch in the 2017–18 season was 92 t below the TAC.
In 2017, Stock Synthesis 3 software was used to assess the Patagonian toothfish stock (Day & Hillary 2017). This integrated two-area assessment fits to tag–recapture, length composition and age-at-length data. The assessment assumes a single stock in the MITF but with spatial structuring of fishing and movement between two areas (northern and southern), with recruitment to both areas. Using this assessment, 2017 female spawning biomass was estimated at 69 per cent of unfished levels (SB0). Following the CCAMLR control rule (which uses a target of 0.50SB0 rather than 0.48SB0), a two-year TAC was calculated for the MITF for 2018–19 and 2019–20, which was robust to a wide array of catch distributions spread among the different fishing areas. The TAC for the 2016–17 and 2017–18 seasons was derived from a 2016 assessment (Day et al. 2016) and the CCAMLR control rule.
Stock status determination
The relatively high estimate of current female spawning biomass (0.69SB0) and the robust nature of the assessment result in the stock being classified as not overfished.The conservative TAC-setting process, based on the application of precautionary CCAMLR control rules, and the maintenance of catch generally below the TAC result in the stock being classified as not subject to overfishing.
26.3 Economic status
Key economic trends
Latency can be variable in this fishery. In the 2017–18 fishing season, the TAC was not fully caught (latency was 20 per cent), and higher effort (longline days) was expended for less catch compared with the previous season. Catch per longline day declined from 4.7 t in 2016–17 to 3.2 t in 2017–18. During the 2017–18 fishing season, there was some loss of gear and difficult operating conditions, which likely raised the daily cost of fishing.
The estimated biomass of 0.69SB0 in 2017 is well above the targeted level of 0.50SB0. This high abundance is likely to result in lower fishing costs and improved profitability. Given that only one operator has fished in the MITF in recent years, it is also likely that individual profit-maximising decisions are aligned with optimum use of the resource, within the constraints of the fishery’s precautionary objective.
The harvest strategy for this fishery is conservative, reflecting the CCAMLR ecosystem-based management approach. Therefore, catch limits aim to maintain stock biomass at levels that are higher than recommended target reference points for other Commonwealth fisheries managed under the HSP.
Average vessel economic performance is likely to have improved since longlining was approved in 2011. The initial demersal longline trial in 2007 found a number of benefits of longline fishing compared with trawl fishing, including increased access to Patagonian toothfish in deeper waters and reduced levels of bycatch (AFMA 2010). These benefits are likely to have improved vessel-level productivity, moderating the negative effects of rough sea conditions experienced in recent years.
26.4 Environmental status
The MITF is included on the List of Exempt Native Specimens under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and has export approval until 9 October 2026. No additional recommendations apply under this exemption, beyond standard recommendations pertaining to reporting.
The ecological risk assessment process was completed to level 3 (Sustainability Assessment for Fishing Effects) for trawling and demersal longline for sharks and scalefish. No species was at high risk from trawling in the MITF (Zhou, Fuller & Smith 2009). The level 3 assessment for demersal longlining used data from 2007 to 2010 and is considered preliminary (Zhou & Fuller 2011). Two species—southern lanternshark (Etmopterus baxteri)and southern sleeper shark (Somniosus antarcticus)—had mean fishing mortality estimated to be slightly higher than the rates corresponding to the maximum number of fish that can be removed in the long term. However, the authors suggested that the level 3 assessment tends to be overly precautionary, and it is likely that the mortality rate was overestimated. This is supported by the low recorded catch for the two species (two southern lantern sharks and nine southern sleeper sharks) over the three years. Further analyses should take place as data become available. The MITF ecological risk management reports for trawling and demersal longline both outline how the Australian Fisheries Management Authority (AFMA) will continue to monitor bycatch, and interactions with protected species under the EPBC Act, in a manner consistent with CCAMLR principles (AFMA 2009, 2011).
All the catch in the MITF is now taken by longline. No seabird or marine mammal interactions were observed in the longline trial. AFMA publishes quarterly logbook reports of interactions with species protected under the EPBC Act on its website. In 2017, no interactions with protected species were recorded.
AFMA 2009, Ecological risk management: report for the Macquarie Island Toothfish Fishery—demersal trawl sub-fishery, Australian Fisheries Management Authority, Canberra.
—— 2010, Assessment of longline fishing in the Macquarie Island Toothfish Fishery, AFMA, Canberra.
—— 2011, Ecological risk management: report for the Macquarie Island Toothfish Fishery—demersal longline sub-fishery, AFMA, Canberra.
Appleyard, SA, Ward, RD & Williams, R 2002, ‘Population structure of Patagonian toothfish around Heard, McDonald and Macquarie Islands’, Antarctic Science, vol. 14, pp. 364–73.
DAFF 2007, Commonwealth Fisheries Harvest Strategy: policy and guidelines, Australian Government Department of Agriculture, Fisheries and Forestry, Canberra.
Day, J & Hillary, R 2017, Stock assessment of the Macquarie Island fishery for Patagonian toothfish (Dissostichus eleginoides), using data up to and including August 2016, CSIRO Marine and Atmospheric Research, Hobart.
——, Wayte, S, Haddon, M & Hillary, R 2016, Stock assessment of the Macquarie Island fishery for Patagonian toothfish (Dissostichus eleginoides), using data up to and including August 2015, CSIRO Marine and Atmospheric Research, Hobart.
UNESCO 1998, Convention Concerning the Protection of the World Cultural and Natural Heritage, twenty-first session of the World Heritage Committee, 1–6 December 1997, United Nations Educational, Scientific and Cultural Organization, Naples, Italy.
Williams, R, Tuck, GN, Constable, AJ & Lamb, T 2002, ‘Movement, growth and available abundance to the fishery of Dissostichus eleginoides Smitt, 1898 at Heard Island, derived from tagging experiments’, CCAMLR Science, vol. 9, pp. 33–48.
Zhou, S & Fuller, M 2011, Sustainability assessment for fishing effects on fish bycatch species in the Macquarie Island Toothfish Longline Fishery: 2007–2010, report to AFMA, Canberra.
——, Fuller, M & Smith, T 2009, Rapid quantitative risk assessment for fish species in seven Commonwealth fisheries, report to AFMA, Canberra.