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Skipjack tuna - Indian Ocean
Marine Resource  Fact Sheet
Stock status report 2020
Skipjack tuna - Indian Ocean
Fact Sheet Citation  
Skipjack tuna Indian Ocean
Owned byIndian Ocean Tuna Commission (IOTC) – More
Related observationsLocate in inventorydisplay tree map
 
Species:
FAO Names: en - Skipjack tuna, fr - Listao, es - Listado, zh - 鲣, ru - Тунец полосатый (=скипджек)

Fishery Indicators
Production: Catch
Geographic extent of Skipjack tuna - Indian Ocean
Main Descriptors
Considered a single stock: Yes        Management unit: Yes
Reference year: 2019
 
 
Biological State and Trend
State & Trend Descriptors
PartnerFIRMS
Exploitation rateNot subject to overfishing (C2019/C40%SSB (80% CI) = 1.02 (0.81–1.18))No or low fishing mortality
Abundance levelNot overfished (SB2019/SB40%SSB (80% CI) = 1.11 (0.95-1.29))Pre-exploitation biomass or high abundance
Habitat and Biology
Climatic zone: Temperate; Tropical.   Horizontal distribution: Oceanic.   Vertical distribution: Pelagic.  

Geographical Distribution
Jurisdictional distribution: Highly migratory

Water Area Overview
 
Geo References
Resource Structure
Considered a single stock: Yes


The tag recoveries from the RTTP-IO [Regional Tuna Tagging Project-Indian Ocean] provide evidence of rapid, large scale movements of skipjack tuna in the Indian Ocean, thus supporting the current assumption of a single stock for the Indian Ocean. Skipjack tuna in the Indian Ocean are considered a single stock for assessment purposes.
Exploitation
 
Fishery Indicators
TypeMeasureValueUnitTime period
ProductionCatch 15013tonnesAverage 1950 - 1959
Catch 26864tonnesAverage 1960 - 1969
Catch 46918tonnesAverage 1970 - 1979
Catch 130121tonnesAverage 1980 - 1989
Catch 319130tonnesAverage 1990 - 1999
Catch 472982tonnesAverage 2000 - 2009
Catch 457382tonnesAverage 2010 - 2019
Catch 378438tonnes2011
Catch 340919tonnes2012
Catch 433829tonnes2013
Catch 424037tonnes2014
Catch 400642tonnes2015
Catch 470148tonnes2016
Catch 505486tonnes2017
Catch 609178tonnes2018
Catch 590450tonnes2019
Catch 555240tonnes2020
Assessment
 

A new stock assessment was carried out for skipjack tuna in 2020 using Stock Synthesis with data up to 2019. The outcome of the 2020 stock assessment model does not differ substantially from the previous assessment (2017) despite the large catches recorded in the period 2018-2019, which exceeded the catch limits established in 2017 for this period. The final overall estimate of stock status indicates that the stock is above the adopted target for this stock and that the current exploitation rate is just below the target.
Assessment Model
Type:  Age-structured
Stock Synthesis III (SS3)
Scientific Advice

The catch limit calculated applying the HCR specified in Resolution 16/02 is 513,572 t for the period 2021-2023. The SC noted that this catch limit is higher than for the previous period. This is attributed to the new stock assessment which estimates a higher productivity of the stock and a higher stock level relative to the target reference point, possibly due to skipjack life history characteristics and favourable environmental conditions. Thus, it is likely that the recent catches that have exceeded the limits established for the period 2018-2020 have been sustained by favourable environmental conditions. Therefore, the Commission needs to ensure that catches of skipjack tuna during this period do not exceed the agreed limit.
Management
Management unit: Yes
Source of information
 
IOTC. 2020. Skipjack tuna. Executive Summary.  Click to openhttps://iotc.org/sites/default/files/Skipjack2020.pdf
IOTC–SC23 2020. Report of the 23rd Session of the IOTC Scientific Committee. Seychelles, 7 – 11 December 2020. IOTC–2020–SC23–R[E]: 211pp.  Click to openhttps://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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