Taxon name
Isurus oxyrinchus
Rafinesque, 1810
Uploaded by
National Red List Database
Taxonomic information
Scientific name
Isurus oxyrinchus
Rafinesque, 1810
Assessed taxon level
Species
Higher level taxonomic groupings
Vertebrates
Fishes
Species authority
Rafinesque, 1810
Location and scope
Specific locality or subnational name or regional name
United Arab Emirates (the)
Scope (of the Assessment)
National
Countries included within the scope of the assessment
United Arab Emirates (the)
Does the assessment cover a marine EEZ area(s)?
Not_assigned
Conservation Status
Assessed as
Near Threatened
Qualifying criteria (if given)
A2d
Criteria system used
IUCN
(see Assessment details)
Assessment rationale/justification
In UAE waters, the Shortfin Mako occurs only in offshore waters of the Sea of Oman. Little is known on the population of this species in UAE waters. It is mostly caught as bycatch in longline, purse seine and drift net fisheries targeting tuna and billfish. Most catches are inadequately recorded and likely underestimated in landings data. There is some evidence of declines in average size of individuals in catches off Oman. It is apparently highly migratory, and has slow life history characteristics including low fecundity and a low annual rate of population increase. Considering this, the species has a low capacity to recover from even moderate levels of exploitation. It is especially susceptible to exploitation (target and bycatch) in many largely unregulated gill net, longline and trawl fisheries that operate within its range outside and surrounding UAE waters. Some management measures are now in place in the Arabian Sea region, although domestic fisheries are likely to continue. 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. It is inferred that declines reported in the Arabian Sea region are representative of its status in the UAE. Based on recorded levels of exploitation, it is suspected to have declined by 20-30% over the past three generation lengths, or about 75 years. It is listed as Near Threatened, nearly meeting the thresholds for Vulnerable A2d.
Assessment details
Assessors/contributors/reviewers listed
UAE National Red List Workshop
Criteria system used
IUCN
Reference for methods given
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.
Further information
Endemism (according to assessment)
Endemic to region
Not assigned
Taxon distribution as listed in assessment
The Shortfin Mako occurs in UAE waters on the Sea of Oman coast. It is excluded from the Arabian Gulf. Globally, it is widespread in temperate and tropical oceanic waters of all oceans from about 50'°N (up to 60'°N in the northeast Atlantic) to 50'°S (Compagno et al. 2005).
Is there a map available in assessment?
Yes
Habitat and systems
Ecological system type
Habitat
Habitat details as listed in assessment
The Shortfin Mako is an offshore littoral and epipelagic species found in tropical and warm-temperate seas to depths of up to 750 m (Compagno 2002, Weigmann 2016). This species reaches a maximum size of about 445 cm total length (TL) (Weigmann 2016). Males reach maturity at about 166-195 cm and females at about 265-280 cm (Pratt and Casey 1983, Stevens 1983, Cliff et al. 1990, Varghese et al. 2017). Age at maturity has been determined in several populations, including New Zealand (7-9 years for males, and 19-21 years for females Bishop et al. (2006)), and the NW Atlantic (eight years for males, and 18 years for females (Natanson et al. 2006)). Longevity has been estimated as 29-32 years (Bishop et al. 2006, Natanson et al. 2006). A study conducted off Brazil reported a longevity of 19-28 years and age at maturity of 7-12 years for females and longevity of 16-23 years and age at maturity of 3-6 years for males (Barreto et al. 2016b).The Shortfin Mako is ovoviviparous and oophagous, but what little is known of its reproductive cycle indicates the gestation period is 15-18 months, with a three year reproductive cycle (Mollet et al. 2002). Litter size is 4-25 pups (possibly up to 30, mostly 10-18), which are about 60-70 cm long at birth (Garrick 1967, Compagno 2001). There are comparatively few records of pregnant females. Among 26 shark species, the Shortfin Mako has an intrinsic rebound potential (a measure of its ability to recover from exploitation) in the mid-range (Smith et al. 1998) with an annual rate of population increase at 0.046 yr<sup>-1</sup>. Cortes (2002) calculated a finite rate of increase (lambda) of 1.141 (1.098 to 1.181 95% CI, r = 0.13) and the average reproductive age as 10.1 (9.2 to 11.1 95% CI) years. Generation length is estimated at 24-25 years based on data for this species from New Zealand and the NW Atlantic (Bishop et al. 2006, Compagno et al. 2005, Natanson et al. 2006).
Threats and conservation measures listed
Threats listed in assessment
In the UAE, sharks have been impacted by targeted commercial fisheries until 2014 when a ban on export of sharks was imposed (Ministry of Climate Change and Environment). Sharks continue to be impacted by artisanal and bycatch fisheries (Annual Fisheries Statistical Report for Abu Dhabi Emirate 2001-2018), though catch data are not species-specific. This species is impacted by bycatch fisheries that are active elsewhere in its range.
Publication
Ralph, G.M., Stump, E., Linardich, C., Bullock, R.W., Carpenter, K.E., Allen D.J., Hilton-Taylor, C., Al Mheiri, R., and Alshamsi, O. 2021. UAE National Red List of Marine Species: Reef-building corals, cartilaginous fishes and select bony fishes. 2021. Ministry of Climate Change and Environment, Dubai, United Arab Emirates.
