Thunnus albacares | UAE National Red List of Marine Species: Reef-building corals, cartilaginous fishes and select bony fishes
Taxa
Thunnus albacares | (Bonnaterre, 1788)
Location
Does the assessment cover a marine EEZ area(s)?
Off
Scope (Assessment)
National
Taxon
Taxonomic Group
Vertebrates
Taxonomic Group Level 2
Fishes
Assessed taxon level
Species
Taxonomic Notes
Although several geographic populations have been named as species, morphological and genetic data show there is one world-wide panmictic species (Gibbs and Collette 1967, Scoles and Graves 1993).
Taxon distribution as listed in assessment
In UAE waters, this species occurs only in the Sea of Oman, and is excluded from the Arabian Gulf. Elsewhere, it is circumglobally distributed in tropical and subtropical waters.
Habitats and Ecology
Ecological system type
Habitat
Habitat details as listed in assessment
This open-water pelagic and oceanic species inhabits waters between 18-31'°C and occurs above and below the thermocline to at least 400 m depth. It schools primarily by size, either in monospecific or multi-species groups. Larger fish frequently school with porpoises and are also associated with floating debris and other objects. It feeds on fishes, crustaceans and squids. Maximum fork length is 240 cm. In the Indian Ocean, longevity is 9 years, length at 50% maturity for males and females is 100 cm and age at first maturity is 3-5 years (IOTC 2018). When applying an age at first reproduction of 4 years and longevity of 9 years, its estimated generation length is 6.5 years based on the following equation recommended by the IUCN Red List methods: Age at first reproduction + (Age at last reproduction - age at first reproduction)/2.
Is there a map available in assessment?
Yes
Assessed status
Asessment status in full
Endangered
Assessment status abreviation
EN
Assessment status criteria
A2bd
Assessment rationale/justification
In the UAE, this pelagic species occurs only in the Sea of Oman where it is taken in both commercial and recreational fisheries. It is heavily targeted by commercial fisheries that operate throughout the Indian Ocean, including the Sea of Oman. Due in part to its highly migratory behavior, the Indian Ocean is considered a single stock by the Indian Ocean Tuna Commission (IOTC). According to the 2018 IOTC stock assessment, this species is overfished with overfishing occurring. Catch has been increasing since 2009, and is currently at an unsustainable level, but effort data are largely lacking, and the 2017 spawning stock biomass (SSB) was at 30% of unfished levels. As of 2009, SSB had declined by 45% over the previous decade (1999-2008). Assuming this decline continued to the present due to increasing catch levels since 2009, a linear regression of estimated adult biomass indicates that the Indian Ocean stock is suspected to have declined by 61% over the past three generation lengths (1999-2019 or 20 years); therefore, it is listed as Endangered A2bd.
About the assessment
Assessors/contributors/reviewers listed
UAE National Red List Workshop
Affliation of assessor(s)/contributors/reviewers listed on assessment
Assessor affiliation specific
Government|IGO
Criteria system
Criteria system specifics
IUCN v3.1 + Regional Guidelines v4.0
Criteria system used
IUCN
Criteria Citation
IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1, Second edition. IUCN, Gland, Switzerland and Cambridge, UK. iv + 32pp pp. And IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN. iii + 41pp.
Endemism
Endemism Notes
Is an endemic?: Not_assigned
Conservation
Threats listed in assessment
Overfishing is a major threat to this species in the UAE in part due to its overfished status across the Indian Ocean stock, in which the Sea of Oman is included (IOTC 2018).
Conservation Measures
Conservation measures:
Scientific Name
Kingdom
Phylum
Class
Order
Family
Genus
Thunnus albacares
Animalia
Chordata
Actinopterygii
Perciformes
Scombridae
Thunnus
