Fishery Report 2020:
Dissostichus eleginoides and Dissostichus mawsoni in Subarea 48.2
CCAMLR Secretariat
16 March 2021
Antarctic toothfish, Dissostichus mawsoni Norman, 1937, and, Patagonian Toothfish, Dissostichus eleginoides Smitt, 1898.
Map of the management areas within the CAMLR Convention Area. Subarea 48.2, the region discussed in this report is shaded in green. Throughout this report, “2020” refers to the 2019/20 CCAMLR fishing season (from 1 December 2019 to 30 November 2020).
1. Introduction to the fishery
1.1. History
Research fishing for Dissostichus spp. in Subarea 48.2 was first conducted by Chile in 1998, when seven hauls were conducted and 36kg of Patagonian toothfish (Dissostichus eleginoides) were caught.
In 2015, Ukraine began a multi-year research program and conducted 29 hauls with a total catch of 31 tonnes of Antarctic toothfish (D. mawsoni) and 4 tonnes of D. eleginoides. Research has continued since 2016 in two Research Blocks (Fig. 1) as part of a multi-year research program in the east of Subarea 48.2.
1.2. Conservation Measures currently in force
Directed fishing for Dissostichus spp. in Subarea 48.2 is prohibited under Conservation Measure 32-02 at least until further scientific information is gathered and reviewed by the Scientific Committee and the Working Group on Fish Stock Assessment (WG-FSA).
Figure 1: Location of the Research Blocks in Subarea 48.2. The fishable depth range (600m-1800m) is highlighted in shades of green.
1.3. Active vessels
In 2019, 3 vessels participated in this fishery.
2. Reported catch
2.1. Latest reports and limits
The total catch reported from research surveys that have been conducted in Subarea 48.2 are shown in Table 1. In this fishery, the catch of D. mawsoni reached a maximum of 35 tonnes in 2019. In 2019, 1 tonnes of D. eleginoides were caught.
The catches reported in Subarea 48.2 include catch data that CCAMLR has agreed should be quarantined as there is no confidence in the amount and/or the location of those catches (SC-CAMLR-38, paragraph 3.56). All ancillary data associated with these vessels (e.g., by-catch, tagging, observer data) are also quarantined and are not included in the data presented in this report.
| Season | Number of vessels | D. eleginoides | D. mawsoni | Estimated IUU catch (tonnes) |
|---|---|---|---|---|
| 1998 | 1 | 0 |
|
|
| 2015 | 1 | 0 (q: 4) | 0 (q: 31) |
|
| 2016 | 2 | 1 (q: 2) | 6 (q: 66) |
|
| 2017 | 3 | 0 (q: 7) | 11 (q: 56) |
|
| 2018 | 5 | 1 (q: 2) | 8 (q: 56) |
|
| 2019 | 3 | 1 | 35 |
|
2.2. By-catch
| Season | Catch Limit (tonnes) | Reported Catch (tonnes) | Catch Limit (tonnes) | Reported Catch (tonnes) | Number Released | Catch Limit (tonnes) | Reported Catch (tonnes) |
|---|---|---|---|---|---|---|---|
| 1998 | 0 | <1 | 0 | <1 | 0 | 0 | <1 |
| 2015 | 12 | <1 q | 3.75 | <1 q | 1 q | 12 | <1 q |
| 2016 | 12 | <1 q | 3.75 | <1 | 82 | 12 | <1 q |
| 2017 | 12 | 3 q | 3.75 | <1 | 452 | 12 | <1 q |
| 2018 | 12 | 3 q | 3.75 | <1 | 206 | 12 | <1 q |
| 2019 | 12 | 5 | 3.75 | <1 | 371 | 12 | <1 |
2.3. Vulnerable marine ecosystems (VMEs)
All Members are required to submit, within their general fisheries notifications requirements, information on the known and anticipated impacts of their gear on vulnerable marine ecosystems (VMEs), including benthic communities and benthos such as seamounts, hydrothermal vents and cold-water corals. All of the VMEs in CCAMLR’s VME Registry are currently afforded protection through specific area closures.
By the end of this fishing season, there were 16 VMEs and no VME Risk Areas designated in Subarea 48.2.
2.4. Incidental mortality of seabirds and marine mammals
There has been no observed seabird mortality reported by vessels from Subarea 48.2 in this fishery.
There has been no observed mammal mortalities reported by vessels from Subarea 48.2 in this fishery.
The requirements of Conservation Measure 25-02, including the ‘Minimisation of the incidental mortality of seabirds in the course of longline fishing or longline fishing research in the Convention Area’ apply to this fishery. There is an exemption to the requirement for night setting by achieving the sink rates described in Conservation Measure 24-02 and subject to a bird by-catch limit.
3. Illegal, Unreported and Unregulated (IUU) fishing
Illegal, unreported and unregulated (IUU) fishing gear was recovered from Subarea 48.2 in March 2016 (CCAMLR-XXXV/10). There has been no other recorded evidence of IUU activities in this region since 2006.
4. Data collection
4.1. Data collection requirements
The collection of biological data under Conservation Measure 23-05 as part of the CCAMLR Scheme of International Scientific Observation (SISO) includes representative samples of length, weight, sex and maturity stage, as well as collection of otoliths for age determination of the target and most frequently taken by-catch species.
4.2. Length frequency distributions
The length frequency distributions of D. mawsoni caught during research are shown in Figure 2. These length frequency distributions are unweighted; they have not been adjusted for factors such as the size of the catches from which they were collected. The interannual variability exhibited in the figure may reflect changes in the fished population but is also likely to reflect changes in the gear used, the number of vessels in the fishery and the spatial and temporal distributions of fishing.
The majority of D. mawsoni caught during research fishing ranged from 125 to 175cm.
Figure 2. Annual length frequency distributions of D. mawsoni caught in Subarea 48.2. The number of hauls from which fish were measured (N) and the number of fish measured (n) in each year are indicated. Note: length frequency distributions are only shown where more than 150 fish were measured.
4.3. Tagging
To date in this area, 1359 D. mawsoni have been tagged and released (17 have been recaptured, 15 of which were released in this area; Table 4), and, 88 D. eleginoides have been tagged and released (0 have been recaptured).
| Season | Tagged | 2016 | 2017 | 2018 | 2019 | Total |
|---|---|---|---|---|---|---|
| 2015 | 156 | 1 | 1 | |||
| 2016 | 346 | 4 | 4 | |||
| 2017 | 349 | 2 | 1 | 1 | 4 | |
| 2018 | 323 | 3 | 3 | 6 | ||
| 2019 | 185 | |||||
| Total | 1359 | 15 |
5. Research
5.1. Status of the science
In 2014, the Scientific Committee endorsed the advice of the Working Group on Fish Stock Assessment (WG-FSA) (SC-CAMLR-XXXIII, Annex 7, paragraph 5.48) that the research plan of Ukraine in Subarea 48.2 proceed in 2015 with an effort limit of 30 lines and catch limit of 75 tonnes of Dissostichus spp. and a tagging rate of 5 toothfish per tonne. This research program was continued in 2016 with the following specific objectives:
to utilise the expertise and experience of crew aboard vessels to explore and locate fishable habitat and sample toothfish in Subarea 48.2
to document the spatial distribution of toothfish species in the area to east of the South Orkney Islands, thus providing catch and biological observations to test and develop the functionality of spatial population models of the north Weddell Sea region
to tag toothfish and collect biological samples to further understand toothfish movement, migration, spawning and stock linkages within Area 48 and adjacent waters.
In 2019, Ukraine reported on its research progress, including data on the distribution of Antarctic toothfish and by-catch, and, biological characteristics (length, weight and age) of Antarctic and Patagonian toothfish (WG-FSA-19/51).
5.2. Research plans
Objectives
Ukraine initiated a three year (2015-2017) research plan using longline gear (trotline) to sample the toothfish populations in Subarea 48.2. The purpose of the research is to characterise the toothfish populations found in that region to better understand stock structure, movement patterns and improve estimates of population characteristics in the northern Weddell/Scotia Sea. The distribution of the two species of Dissostichus overlaps in this area. Additional outcomes of the research relate to mapping of the fishable area, documenting relative abundance of D. eleginoides and D. mawsoni, tagging toothfish for biomass estimation and for stock linkage studies, input into spatial population models and collecting information on distribution, relative abundance and life history of by catch species.
The Ukrainian research was continued after 2017 and the vessel Simeiz undertook research fishing in 2018.
In 2016, the United Kingdom proposed to undertake a 3-year research survey in the eastern part of Subarea 48.2 (also extending into Subarea 48.4). The aim of the UK study is to understand the connectivity of toothfish stocks between Subareas 48.2 and 48.4. The specific objectives of the survey are:
determine population connectivity of D. eleginoides and D. mawsoni between Subareas 48.2 and 48.4 adjacent to the established fishery in Subarea 48.4
expand information on population structures of D. eleginoides and D. mawsoni in Subareas 48.2 and 48.4 adjacent to established fishery in Subarea 48.4
improve data on bathymetry and associated distributions of target and benthic by-catch species, improve data available to CCAMLR on bathymetric features.
The UK vessel Argos Froyanes and the New Zealand vessel San Aspiring undertook research fishing in 2018 for the UK research survey.
5.3. Advice by the Scientific Committee
Research fishing in Subarea 48.2 is conducted under Conservation Measure 24-01 and the research catch limits that apply to this research are set out in Table 2.
6. Stock status
6.1. Summary of current status
As a data-limited fishery, this fishery does not have such estimates.
6.2. Year of last assessment, year of next assessment
Research plans for data-limited fisheries are reviewed annually.
7. Climate Change and environmental variability
A recent summary of the potential impacts of climate change on Southern Ocean fisheries (FAO 2018) highlights the following key points:
The Antarctic region is characterized by complex interaction of natural climate variability and anthropogenic climate change that produce high levels of variability in both physical and biological systems, including impacts on key fishery taxa such as Antarctic krill.
The impact of anthropogenic climate change in the short-term could be expected to be related to changes in sea ice and physical access to fishing grounds, whereas longer-term implications are likely to include changes in ecosystem productivity affecting target stocks.
There are no resident human populations or fishery-dependent livelihoods in the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) Area, therefore climate change will have limited direct implications for regional food security. However, as an “under-exploited” fishery, there is potential for krill to play a role in global food security in the longer term.
The institutional and management approach taken by CCAMLR, including the ecosystem-based approach, the establishment of large marine protected areas, and scientific monitoring programmes, provides measures of resilience to climate change.
There is no formal evaluation of the impacts of climate change and environmental variability available for this particular fishery.