Fisheries and Resources Monitoring System

Black Marlin - Indian Ocean
Marine Resource  Fact Sheet
Stock status report 2016
Black Marlin - Indian Ocean
Fact Sheet Citation  
Black marlin Indian Ocean
Owned byIndian Ocean Tuna Commission (IOTC) – More
Related observationsLocate in inventorydisplay tree map
FAO Names: en - Black marlin, fr - Makaire noir, es - Aguja negra

Fishery Indicators
Production: Catch
Geographic extent of Black Marlin - Indian Ocean
Main Descriptors
Considered a single stock: Yes        Management unit: Yes
Reference year: 2015
Biological State and Trend
State & Trend Descriptors
Exploitation rateSubject to overfishing (F2015/FMSY (80% CI) = 2.42 (1.52–4.06))High fishing mortality
Abundance levelOverfished (B2015/BMSY (80% CI) = 0.81 (0.55–1.10))Low 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

No information on stock structure is currently available in the Indian Ocean; thus for the purposes of assessment, one pan-ocean stock is assumed.
Fishery Indicators
TypeMeasureValueUnitTime period
ProductionCatch 912tonnesAverage 1950 - 1959
Catch 1719tonnesAverage 1960 - 1969
Catch 1480tonnesAverage 1970 - 1979
Catch 2679tonnesAverage 1980 - 1989
Catch 5189tonnesAverage 1990 - 1999
Catch 10162tonnesAverage 2000 - 2009
Catch 11852tonnes2006
Catch 9976tonnes2007
Catch 10951tonnes2008
Catch 11381tonnes2009
Catch 10044tonnes2010
Catch 11447tonnes2011
Catch 13418tonnes2012
Catch 14920tonnes2013
Catch 18103tonnes2014
Catch 18490tonnes2015

Two models (ASPIC and Bayesian state space Surplus Production Model) were applied to the Black marlin in 2016. Both models indicated that the stock is overfished and subject to overfishing. The WPB [Working Party on Billfish of the IOTC] agreed to use the results from the Bayesian state space Surplus Production Model for stock status advice. 
Assessment Model
Type:  Biomass-aggregated
Bayesian Surplus Production Model – State-Space (BSP-SS)
A Stock-Production Model Incorporating Covariates (ASPIC)
Scientific Advice

The current catches of BUM [black marlin] (average of 17171 t in the last 3 years, between 2013-2015) are considerably higher than MSY (9932 t) and the stock is overfished (Bcurr< BMSY) and currently subject to overfishing (Fcurr> FMSY). Even with a 40% reduction in current catches, it is very unlikely (less than 5%) to achieve the Commission objectives of being in the green zone of the Kobe Plot by 2025. Current catch levels are not sustainable and there is a need for urgent actions to decrease this catch levels.
Management unit: Yes
Source of information
IOTC–WPB14 2016. Report of the 14thSession of the IOTC Working Party on Billfish. Victoria, Seychelles, 2016. IOTC–2016–WPB14–R[E]: 94 pp.  Click to open
Black marlin supporting information for the 14th Session of the IOTC Working Party on Billfish. 2016.  Click to open
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