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Fact Sheet Title Fact Sheet |
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Blue marlin - Indian Ocean |
| 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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ident Block | ident Block | | Species List: | Species Ref: en - Blue marlin, fr - Makaire bleu, es - Aguja azul, ar - مقير أزرق أطلسيّ ، مكيرأزرق أطلسيّ, zh - 蓝枪鱼, ru - Марлин синий |
Fishery IndicatorsProduction: Catch |
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| ident Block Blue marlin - Indian Ocean Map tips - Click on to turn layers on and off
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fao Major |
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51 | Indian Ocean, Western |
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57 | Indian Ocean, Eastern |
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Aq Res | Biological Stock: Yes Management unit: Yes Reference year: 2017 |
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. |
| | | | Habitat Bio Climatic Zone: Temperate; Tropical. Horizontal Dist: Oceanic. Vertical Dist: Pelagic. Geo Dist Geo Dist: Highly migratory Geo Dist | Geo Dist Blue marlin - Indian Ocean
fao Major | 51: Indian Ocean, Western | 57: Indian Ocean, Eastern |
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Geo DistBlue marlin - Indian Ocean fao Major | 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 |
Aq Res Struct Biological Stock: Yes No information on stock structure is currently available in the Indian Ocean; thus for the purposes of assessment, one pan-ocean stock is assumed. However, spatial heterogeneity in stock indicators (catch–per–unit–effort trends) for other billfish species indicates that there is potential for localised depletion. Exploit Fishery Indicators Type | Measure | Value | Unit | Time period |
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Production | Catch | 2574 | tonnes | Average 1950 - 1959 | Catch | 3546 | tonnes | Average 1960 - 1969 | Catch | 3550 | tonnes | Average 1970 - 1979 | Catch | 5113 | tonnes | Average 1980 - 1989 | Catch | 7629 | tonnes | Average 1990 - 1999 | Catch | 8696 | tonnes | Average 2000 - 2009 | Catch | 8987 | tonnes | Average 2010 - 2019 | Catch | 9018 | tonnes | 2011 | Catch | 11965 | tonnes | 2012 | Catch | 8577 | tonnes | 2013 | Catch | 6955 | tonnes | 2014 | Catch | 8506 | tonnes | 2015 | Catch | 9701 | tonnes | 2016 | Catch | 9889 | tonnes | 2017 | Catch | 8536 | tonnes | 2018 | Catch | 8424 | tonnes | 2019 | Catch | 6956 | tonnes | 2020 |
Bio Assess No new stock assessment for blue marlin was carried out in 2021 so the stock status is based on the 2019 assessment conducted using the Bayesian State-Space Surplus Production model JABBA which suggests that there is an 87% probability that the Indian Ocean blue marlin stock in 2017 is in the red zone of the Kobe plot, indicating the stock is overfished and subject to overfishing (B2017/BMSY=0.82 and F2017/FMSY=1.47) as shown in Table 1 and Fig. 2. The most recent catch is lower than the estimate of MSY (Catch2019 = 8,486 t; MSY = 9,984 t). The previous assessment of blue marlin concluded that in 2015 the stock was subject to overfishing but not overfished. The change in stock status can be attributed to increased catches for the period 2015-2017 as well as improved standardisation of CPUE indices, which includes the area disaggregation of JPN and TWN indices to account for fleet dynamics. Assess Models Type: Biomass-aggregated Sci Advice The current catches of blue marlin (average of 8,701 t in the last 5 years, 2016-2020) are lower than MSY (9,984 t). The assessment conducted in 2017 indicated that the stock was overfished and subject to overfishing. In order to achieve the Commission objectives of being in the green zone of the Kobe Plot by 2027 (F2027 < FMSY and B2027 > BMSY) with at least a 60% chance, the catches of blue marlin would have to be reduced by 35% compared to the average of the last 3 years, to a maximum value of approximately 7,800 t. Management Management unit: Yes Sources 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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