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Marine Resource Fact Sheet |
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| Data Ownership | This document provided, maintained and owned by Indian Ocean Tuna Commission (IOTC) , is part of IOTC Stock Status Reports data collection. |
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Related observations | Locate in inventory | | Species: | FAO Names: en - Swordfish, fr - Espadon, es - Pez espada, ru - Меч-рыба |
Fishery IndicatorsProduction: Catch |
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| Geographic extent of Swordfish - Indian Ocean Map tips - Click on
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FAO Major Fishing Areas |
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51 | Indian Ocean, Western |
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57 | Indian Ocean, Eastern |
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Main Descriptors | Considered a single stock: Yes Management unit: Yes Reference year: 2018 |
Considered a single stock: A group of individuals in a species occupying a well defined spatial range independent of other stocks of the same species. It can be affected by random dispersal movements and directed migrations due to seasonal or reproductive activity. |
Spatial Scale: Spatial scale contains a standard term such as Global, Regional (e.g. for the whole Atlantic), sub-regional (e.g. for a part of the Atlantic), national, local (for sub-national levels). |
Considered a management unit: An aquatic resource or fishery is declared as [Fishery] Management Unit if it is effectively the focus for the application of selected management methods and measures, within the broader framework of a management system. According to the FAO Glossary for Responsible Fishing, "a Fishery Management Unit (FMU) is a fishery or a portion of a fishery identified in a Fishery Management Plan (FMP) relevant to the FMP's management objectives." FMU's may be organised around fisheries biological, geographic, economic, technical, social or ecological dimensions , and the makeup and attribute of a fishery management unit depends mainly on the FMP's management objectives. |
Jurisdictional distribution: Jurisdictional qualifier (e.g. "shared", "shared - highly migratory") of the aquatic resource related with its spatial distribution. |
Environmental group: Classification of the aquatic resource according to the environmental group (e.g. pelagic invertebrate, or demersal fish) to which the species belong. |
Reference Year: The Reference Year is the last year considered in the stock assessment and/or fishery status. |
| | | | Biological State and Trend Habitat and Biology Climatic zone: Temperate; Tropical. Horizontal distribution: Oceanic. Vertical distribution: Pelagic. Geographical Distribution Jurisdictional distribution: Highly migratory Geo References  | Geographic extent of Swordfish - Indian Ocean
FAO Major Fishing Areas | 51: Indian Ocean, Western | 57: Indian Ocean, Eastern |
| | | | Intersecting Major FAO areas and LME areas |
The following area codes have been found as intersecting the distribution of Swordfish - Indian Ocean FAO Major Fishing Areas | 51: Indian Ocean, Western | 57: Indian Ocean, Eastern | Large Marine Ecosystem Areas (LME) | 30: Agulhas Current | 31: Somali Coastal Current | 32: Arabian Sea | 33: Red Sea | 34: Bay of Bengal | 38: Indonesian Sea | 39: North Australian Shelf | 42: Southeast Australian Shelf | 43: Southwest Australian Shelf | 44: West-Central Australian Shelf | 45: Northwest Australian Shelf |
Resource Structure Considered a single stock: Yes A recent genetic study did not reveal any structure within the Indian Ocean with the markers used, however the hypothesis of a population structuring at the regional level cannot be discarded and needs to be investigated using different markers or approaches. Results obtained from the markers used may simply be a matter of the resolving power of the markers used, which may simply have been insufficient for detecting population subdivision. Spatial heterogeneity in stock indicators (catch–per–unit–effort trends) indicates the potential for localised depletion of swordfish in the Indian Ocean. Exploitation Fishery Indicators Type | Measure | Value | Unit | Time period |
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Production | Catch | 297 | tonnes | Average 1950 - 1959 | Catch | 1340 | tonnes | Average 1960 - 1969 | Catch | 2106 | tonnes | Average 1970 - 1979 | Catch | 5093 | tonnes | Average 1980 - 1989 | Catch | 26011 | tonnes | Average 1990 - 1999 | Catch | 32292 | tonnes | Average 2000 - 2009 | Catch | 28935 | tonnes | Average 2010 - 2019 | Catch | 21320 | tonnes | 2011 | Catch | 26785 | tonnes | 2012 | Catch | 30091 | tonnes | 2013 | Catch | 27270 | tonnes | 2014 | Catch | 31362 | tonnes | 2015 | Catch | 30743 | tonnes | 2016 | Catch | 32937 | tonnes | 2017 | Catch | 31017 | tonnes | 2018 | Catch | 33589 | tonnes | 2019 | Catch | 25913 | tonnes | 2020 |
Assessment A new assessment was undertaken in 2020 using stock synthesis with fisheries data up to 2018. The assessment uses a spatially disaggregated, sex explicit and age structured model. The SS3 model, used for stock status advice, indicated that MSY-based reference points were not exceeded for the Indian Ocean population as a whole (F2018/FMSY< 1; SB2018/SBMSY> 1). The two alternative models (ASPIC and JABBA) applied to swordfish also indicated that the stock was above a biomass level that would produce MSY. Spawning biomass in 2018 was estimated to be 40-83% of the unfished levels. Most recent catches of 33,590 t in 2019 are approximately at the MSY level (33,000 t). On the weight-of-evidence available in 2020, the stock is determined to be not overfished and not subject to overfishing (Table 1, Fig. 2). Assessment Model Type: Age-structured Stock Synthesis III (SS3) Scientific Advice The most recent catches (33,590 t in 2019) are at approximately the MSY level (33,000 t). Under the current levels of catches, the spawning biomass is projected to remain relatively stable, with a high probability of maintaining at or above the SBMSY for the longer term. Nevertheless, the Commission should consider limiting the catches so as not to exceed the 2018 catch level (30,847 t at the time of the assessment) to ensure that the probability of exceeding the SBMSY target reference points in the long term remains minimal (2%). Projections indicate that an increase of 40% or more from 2018 catch levels will likely result in the biomass dropping below the SBMSY level for the longer term (>75% probability). Taking into account the updated information regarding swordfish stock structure (IOTC-2020-WPB18-09), as well as the differential CPUE and biomass trends between regions, the WPB should continue to discuss the swordfish stock assessment model specifications and consider the feasibility of including a multi-stock assessment in 2023. Recognising that there is recurring evidence for localised depletion in the southern regions (particularly the South West) the WPB expresses concern and suggests this should be further monitored. Management Management unit: Yes Source of information IOTC–SC23 2020. Report of the 23rd Session of the IOTC Scientific Committee. Seychelles, 7 – 11 December 2020. IOTC–2020–SC23–R[E]: 211pp. https://www.iotc.org/sites/default/files/documents/2021/06/IOTC-2020-SC23-RE_Rev1.pdf Bibliography All references to figures, tables and bibliography in the text are found within the source of information. |
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