Aetobatus ocellatus | UAE National Red List of Marine Species: Reef-building corals, cartilaginous fishes and select bony fishes
Taxa
Aetobatus ocellatus | (Kuhl, 1823)
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
Aetobatus ocellatus (Kuhl, 1823) was previously considered to be an Indo-West and Central Pacific form of the wider ranging Aetobatus narinari (Euphrasen, 1790). Comparative analysis of the morphology, molecular and parasite diversity has resulted in the redescription of A. ocellatus from tropical and warm-temperate waters of the Indian Ocean and West-Central Pacific Ocean with A. narinari being restricted to the Atlantic Ocean (Richards et al. 2009, White et al. 2010). Molecular analyses suggest greater levels of speciation within the Aetobatus genus, with distinguishable groups in the Western Indian Ocean and Northwest Pacific (Schluessel et al. 2010, White et al. 2010). Samples from Qatar cluster separately -- designated as A. cf. ocellatus 2 (D. Ebert pers. comm. 2017). This requires further examination to delineate species boundaries.
Taxon distribution as listed in assessment
The Spotted Eagle Ray occurs throughout UAE waters. Globally, it is widespread in the Indo-West-Central Pacific (Last et al. 2016).
Habitats and Ecology
Ecological system type
Habitat
Habitat details as listed in assessment
The Spotted Eagle Ray is found in tropical and warm-temperate waters in coastal regions and over the continental shelf from the surface up to 40 m depth (Weigmann 2016). It sometimes enters lagoons and estuaries and is often associated with coral reef ecosystems (Homma et al. 1994, Last and Stevens 2009). It is also encountered well offshore in open water (Last et al. 2010). It attains a maximum size of 330 cm disc width (DW), but the species is more commonly observed to about 160 cm DW (Last et al. 2010). This species is reported to reach sexual maturity after 4-6 years (Last and Stevens 2009). Size at maturity is reported as 150-160 cm DW (Schluessel et al. 2010, Last et al. 2016) for females, and between 119-130 cm DW for males (Schluessel et al. 2010, Moore et al. 2012). Size at birth is 33-36 cm DW (Last et al. 2010). Reproduction is viviparous with aplacental histotrophy (Last et al. 2010). Little information is available on reproductive biology, although it is known to have up to 10 pups but usually about four pups per litter (Last et al. 2016). Gestation has been reported at 12 months and reproductive periodicity may not be annual (Schluessel et al. 2010). Generation length was inferred as ~15 years based on data for the Bat Ray (Myliobatis californicus) which are reported to have a maximum age of 24 years and an age at maturity of five years (Martin and Cailliet 1988).
Is there a map available in assessment?
Yes
Assessed status
Asessment status in full
Vulnerable
Assessment status abreviation
VU
Assessment status criteria
A2cd
Assessment rationale/justification
This inshore and offshore eagle ray occurs throughout UAE waters. The species inhabits lagoons and estuaries and is often associated with coral reefs. It may be taken as bycatch in certain fisheries. Most of the distribution of the species in the Arabian Sea region is under extremely intense and increasing demersal fishing pressure, especially off Iran, India and Pakistan; although, pressure is thought to be lower in the western part of the Arabian Sea, which includes the UAE. Furthermore, the loss and modification of coastal habitats across the region is a significant concern. Its relative rarity, large size and low productivity makes this species particularly susceptible to population decline as a result of fishing pressure and coastal development. Though data specifically from the UAE are not available, individuals in the UAE are a component of a larger, interconnected and migratory population that occurs broadly in the north-western Indian Ocean. Given the intense fishing pressures faced by this species throughout the Arabian Seas, and ongoing threats from bycatch and habitat loss, it is inferred that declines reported in the Arabian Seas are representative of the status in the UAE. Based on recorded levels of exploitation and declines in habitat quality, it is suspected to have declined by 30-50% over the past three generation lengths, or about 45 years. It is listed as Vulnerable A2cd.
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
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
The Spotted Eagle Ray is highly susceptible to a variety of inshore demersal fisheries, including trawls and gill nets. Its small litter size, schooling behaviour, inshore habitat and hence availability to a wide variety of inshore fishing gear (beach seine, gillnet, purse seine, benthic longline, trawl, etc.), and the generally intense and unregulated nature of inshore fisheries across large parts of the species' range, pose significant risks to the Arabian Sea population. The occurrence of this species in coral reef areas make it susceptible to habitat degradation and coastal development, pollution, and the effects of climate change (Normile 2016). In the Arabian Gulf, there are major impacts from from development activities (including dredging and reclamation), desalination plants, industrial activities, habitat destruction through the removal of shallow productive areas and major shipping lanes (Sheppard et al. 2010). Corals in the UAE and Arabian Gulf have severely declined due to the increasing frequency of mass bleaching events caused by rising water temperatures, which is a consequence of climate change, as well as pervasive coastal development (Riegl et al. 2018, Burt et al. 2019).
Conservation Measures
Conservation measures:
Scientific Name
Kingdom
Phylum
Class
Order
Family
Genus
Aetobatus ocellatus
Animalia
Chordata
Chondrichthyes
Myliobatiformes
Aetobatidae
Aetobatus
