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| Marine Resource Fact Sheet |
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| Black marlin - Indian Ocean |
 | Black 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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| Related observations | Locate in inventory | | | | Species: | | FAO Names: en - Black marlin, fr - Makaire noir, es - Aguja negra |
Fishery IndicatorsProduction: Catch |
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| Geographic extent of Black marlin - 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: 2019 |
| 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 Black marlin - 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 Black marlin - 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 No information on stock structure is currently available in the Indian Ocean; thus for the purposes of assessment, one pan-ocean stock is assumed. Exploitation Fishery Indicators | Type | Measure | Value | Unit | Time period |
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| Production | Catch | 912 | tonnes | Average 1950 - 1959 | | Catch | 1719 | tonnes | Average 1960 - 1969 | | Catch | 1483 | tonnes | Average 1970 - 1979 | | Catch | 2667 | tonnes | Average 1980 - 1989 | | Catch | 4891 | tonnes | Average 1990 - 1999 | | Catch | 10325 | tonnes | Average 2000 - 2009 | | Catch | 16320 | tonnes | Average 2010 - 2019 | | Catch | 13370 | tonnes | 2011 | | Catch | 12902 | tonnes | 2012 | | Catch | 14813 | tonnes | 2013 | | Catch | 18276 | tonnes | 2014 | | Catch | 19122 | tonnes | 2015 | | Catch | 22397 | tonnes | 2016 | | Catch | 15215 | tonnes | 2017 | | Catch | 18786 | tonnes | 2018 | | Catch | 18068 | tonnes | 2019 | | Catch | 16974 | tonnes | 2020 |
Assessment Level of uncertainty: High A stock assessment based on JABBA, a Bayesian state-space production model (age-aggregated) was conducted in 2021 for black marlin. The Kobe plot from the JABBA model indicated that the stock is not subject to overfishing and is currently not overfished, however these status estimates are subject to a high degree of uncertainty. Since 2018, there has been no discernible improvement in the data available for black marlin and the subsequent assessment outputs remain uncertain and should be interpreted with caution. As such, there is no reasonable justification to change the stock status from “Not assessed/Uncertain”. Assessment Model Type: Biomass-aggregated Scientific Advice The 2020 catches (16,977 t) (Fig. 1) were substantially higher than the MSY limits stipulated in Res (18/05) which is 9,932 t. The Commission should provide mechanisms to ensure that catch limits are not exceeded by all concerned fisheries. Projections were not carried out due to the poor predictive capabilities identified in the assessment diagnostics. 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.pdfBibliography All references to figures, tables and bibliography in the text are found within the source of information. |
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