The Australian external territory of Heard Island and McDonald Islands (HIMI) is in the southern Indian Ocean (Figure 25.1), within the area covered by the Convention on the Conservation of Antarctic Marine Living Resources. The islands and their surrounding territorial waters (out to 12 nautical miles [nm]) are closed to fishing and regulated under the Environment Protection and Management Ordinance 1987, administered by the Australian Antarctic Division (AAD) of the Australian Government Department of the Environment and Energy. A 1 nm buffer zone around the territorial waters of HIMI extends the area closed to fishing to 13 nm. The HIMI Marine Reserve was declared in October 2002 and then expanded in March 2014 by proclamation after scientific assessment. The reserve now totals 71,200 km2. Waters between 12 and 200 nm from HIMI are part of the Australian Fishing Zone (AFZ). The Heard Island and McDonald Islands Marine Reserve management plan 2014–2024 (2014), made pursuant to the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), provides the management regime for the reserve.
Fishing methods and key species
The key target species are Patagonian toothfish (Dissostichus eleginoides) and mackerel icefish (Champsocephalus gunnari).The fishery also has catch limits for bycatch species, such as deep-sea skates (Rajidae) and grey rockcod (Lepidonotothen squamifrons), based on assessments of long-term annual yield (Constable, Williams & de la Mare 1998). The catch limits for unicorn icefish (Channichthys rhinoceratus) and grenadiers (Macrourus spp.), another group of bycatch species, were updated in 2015 based on assessments undertaken by the AAD (Dell et al. 2015; Maschette & Dell 2015). The catch limits are regularly reviewed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) Scientific Committee and the CCAMLR Commission, and are considered precautionary. Demersal longline is the main method used in the fishery, with some catch taken by demersal trawl. Trawl has declined rapidly in favour of longline as the main method used to target toothfish. Mackerel icefish are taken exclusively using demersal and midwater trawl.
The AAD, in collaboration with industry, regularly conducts fisheries-independent, random-stratified trawl surveys for target species (Patagonian toothfish and mackerel icefish) to collect relative abundance data, particularly of juvenile age classes. Harvest strategies for the target species are consistent with the precautionary approach implemented by the CCAMLR and have been used to set catch limits since the mid 1990s. The harvest strategies developed for the Heard Island and McDonald Islands Fishery (HIMIF) are considered more precautionary than the guidelines of the Commonwealth Fisheries Harvest Strategy Policy (DAFF 2007). For mackerel icefish, the reference point dictates that the spawning stock biomass be maintained at 75 per cent of the level that would occur in the absence of fishing at the end of a two-year model projection. 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 the 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 importance of the target species (especially mackerel icefish) as prey in the subantarctic ecosystem is taken into account, and catch limits must be sufficiently precautionary to ensure that the abundance of these species meets the ecological needs of dependent species (for example, seabirds and marine mammals). Mackerel icefish in the HIMIF was initially certified as sustainable by the Marine Stewardship Council (MSC) in March 2006 and was recertified in July 2016. Patagonian toothfish in the HIMIF was recertified as sustainable by the MSC in July 2017.
Illegal, unreported and unregulated (IUU) longline fishing within the HIMI AFZ, targeting Patagonian toothfish, was a significant problem from the mid 1990s. However, following Australian surveillance and enforcement activities in the area (in cooperation with adjoining nations in the CCAMLR region, notably France), no IUU fishing vessels have been detected since 2004 inside the Australian Exclusive Economic Zone (EEZ) adjacent to HIMI or the French EEZ surrounding the Kerguelen Islands.
Effort in the HIMIF has been fairly stable, with two to four vessels active at any one time since a total allowable catch (TAC) was first set in the mid 1990s. However, as a result of a higher TAC, seven vessels were active in 2014–15. Four vessels were active in 2016–17.
Catches of mackerel icefish have been variable over time. It is a short-lived species, exhibiting periodic, large, dominant year-classes. This allows high catches for a year or two. Once that year-class dies out and the next cohort is growing, catches are reduced because less biomass is available to the fishery.
Catches of Patagonian toothfish have been more stable over time, with little variation between 2000–01 and 2013–14. Catch in the 2014–15 fishing season increased in response to the increased TAC. Catch in 2015–16 was below the TAC by 606 t. This was due to a decrease in catch rates during the fishing season. Possible reasons for this drop in catch rates are currently being investigated by the Sub-Antarctic Resource Assessment Group of the Australian Fisheries Management Authority (AFMA), and may relate to environmental factors.
TABLE 25.2 Main features and statistics for the HIMIF
Fishery statistics a
2015–16 fishing season
2016–17 fishing season
Real value (2015–16)
Real value (2016–17)
|Mackerel icefish||482||491 b||Confidential||561||557||Confidential|
0 pots hauled
0 pots hauled
|Fishing permits||4 quota SFR holders||4 quota SFR holders|
|Active vessels c||7||4|
|Observer coverage||100% vessel coverage||100% vessel coverage|
|Fishing methods||Demersal longline, demersal trawl, midwater trawl, pot (fish traps)|
|Primary landing ports||Port Louis (Mauritius), Nelson (New Zealand)|
|Management methods||Input controls: limited entry, gear restrictions, temporal and spatial closures|
Output controls: TACs, ITQs
Other: move-on provisions if bycatch thresholds are reached
|Primary markets||International: China, eastern Europe, Japan, United States—frozen|
|Management plan||Heard Island and McDonald Islands Fishery Management Plan 2002 (amended 2011)|
a Fishery statistics are provided by fishing season, unless otherwise indicated. Season is 1 December to 30 November. Real-value statistics are by financial year.
b 9 t will be deducted from the 2016–17 season quota to take account of the overcatch.
c 14 t was deducted from the 2014–15 season quota to take account of the overcatch of the previous year. d All vessels carry two observers on each trip.
ITQ Individual transferable quota.
SFR Statutory fishing right.
TAC Total allowable catch.
Mackerel icefish (Champsocephalus gunnari)
Line drawing: FAO
A single stock of mackerel icefish is considered to exist at HIMI; no genetic variation among sites around HIMI has been found (Williams, Smolenski & White 1994). Genetic studies have indicated that the population at HIMI is distinct from other icefish populations in the southern Atlantic Ocean (Kuhn & Gaffney 2006). Mackerel icefish at HIMI and the Kerguelen Plateau in the French EEZ are considered distinct stocks because of their different spawning seasons and growth rates (Williams et al. 2001).
The catch history of icefish has been sporadic, with very high and unregulated catches taken by Soviet and Polish fleets across the Kerguelen Plateau in the 1970s, before the declaration of the EEZ around the Kerguelen Islands by France and the AFZ around HIMI. Considerable uncertainty exists about where these earlier catches were taken relative to the current maritime boundaries, although charts from this period indicate that the fishing fleet was aware of some of the banks where icefish currently form aggregations within the Australian EEZ. The initial TAC for icefish was set by the CCAMLR in 1995 following a demersal survey by the AAD. Since then, catches have generally followed the TAC, which takes into account the large natural fluctuations in abundance of the fish (Figure 25.2), except for 2014–15, when catches were well under the TAC. This was a result of fishers concentrating their efforts in 2014–15 on the more valuable Patagonian toothfish, for which the TAC was higher than in recent years.
A random stratified trawl survey in April 2017 provided information on the abundance and age structure of the mackerel icefish stock (Nowara, Lamb & Ziegler 2017). The 3+ year-class was estimated to account for 97 per cent of the biomass (Maschette et al. 2017). The stock assessment estimated the current biomass at 3,901 t (Maschette et al. 2017). Although the growth parameters used in the assessment were updated, there was only a small impact on the yields. Yields of 526 t for the 2017–18 season and 395 t for the 2018–19 season were estimated to satisfy the CCAMLR decision rules, assuming that the entire 2017–18 TAC was taken. A TAC of 526 t for the 2017–18 season and a TAC of 395 t for the 2018–19 season (subject to revision) were endorsed by the CCAMLR (CCAMLR 2017a, b).
Stock status determination
Based on the level of catch, the harvest rate relative to the stock biomass estimate (which, under the harvest strategy, allows for a high rate of escapement) and the robust nature of the assessment (which includes fisheries-independent data), the stock is determined to be not overfished and not subject to overfishing.
Patagonian toothfish (Dissostichus eleginoides)
Line drawing: FAO
The Patagonian toothfish stock at HIMI is considered to comprise a population distinct from other regional toothfish populations in the south-west Pacific and Atlantic oceans (Appleyard, Ward & Williams 2002). However, limited genetic variation has been found among populations in the western Indian Ocean sector of the Southern Ocean (that is, HIMI, Crozet Islands, Kerguelen Islands, Marion Island and Prince Edward Islands; Appleyard, Williams & Ward 2004; Toomey et al. 2016). Data from tagging studies (for example, Welsford et al. 2011; Williams et al. 2002) indicate that, although adult toothfish at HIMI are relatively sedentary and usually recaptured within 15 nm of their point of release, in some cases they travel significant distances. For example, toothfish tagged at HIMI have been recaptured approximately 800 nm and 1,000 nm away on the Kerguelen and Crozet plateaus, respectively. Thus, toothfish in the Indian Ocean sector of the Southern Ocean may form a metapopulation, with some limited connectivity between the populations. The stock structure of toothfish on the Kerguelen Plateau is being further investigated in collaboration with French scientists so that population models of toothfish in the area can be refined and management can be improved across the Kerguelen Plateau (Péron et al. 2016; Welsford et al. 2011). For the purposes of the assessment, the HIMI toothfish population is considered to be distinct.
Catch of Patagonian toothfish in the HIMIF has declined slightly since the late 1990s, but was relatively stable from the early 2000s to 2013–14 and has mirrored the TAC (Figure 25.3). Because of the higher TAC, catches were greater in 2014–15 and the highest since 1994–95. As noted above, catch rates dropped in the 2015–16 fishing season, but catch in 2016–17 was very close to the TAC.
The most recent assessment for Patagonian toothfish (Ziegler 2017) was similar to the 2015 assessment, and included updated survey and ageing data, updated growth parameters, updated maturity parameters, updated tag loss estimates, a bias correction for fish emigration, the use of survey biomass and catch proportions instead of abundance numbers, and iterative data weighting (the ‘Francis’ method; Francis 2011). The assessment was run using the agreed version of CASAL.
The assessment agreed by the 2017 Working Group on Fish Stock Assessment estimated that the spawning biomass was 61 per cent of unfished levels (SB2016/SB0 = 0.61; range 0.58–0.64). A catch limit of 3,525 t satisfied the CCAMLR decision rules, and was the recommended TAC for the 2017–18 and 2018–19 fishing seasons (CCAMLR 2017a, b). This TAC is slightly higher than that set for 2015–16 and 2016–17 because the updated maturity parameters indicated higher productivity, which resulted in a higher TAC under the decision rules.
Stock status determination
Given the relatively high spawning biomass, the precautionary TAC that satisfies the CCAMLR decision rules, the robust nature of the stock assessment and the extensive CCAMLR review process, the stock is classified as not overfished and not subject to overfishing.
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