Manta rays (Manta spp.)
Photo: NOAA's Flower Garden Banks National Marine Sanctuary
Did You Know?
· Manta rays are the only vertebrate animals with 3 paired appendages.
Manta rays were split into two species in 2009:
- Manta alfredi (added in 2009)
- Manta birostris
Additionally, a third species in the Caribbean may soon be named.
This page includes information on all the Manta species.Species Description
|Weight:||M. birostris: up to 5,300 pounds (2,400 kg)
M. alfredi: up to 3,000 pounds (1,350 kg)
|Length:||M. birostris: 25 feet (8 m)
M. alfredi: 15.5 feet (5 m)
|Appearance:||large diamond-shaped body with black backs and a mostly white belly, some have species- and individual-specific black markings|
|Lifespan:||about 40 years; they reach sexual maturity at 10 years|
|Behavior:||Gestation is thought to last 10-14 months, and they typically give birth to one pup every 2-3 years.|
Manta rays are slow-growing, large-bodied migratory animals with small, highly fragmented populations that are sparsely distributed across the tropics of the world. They are characterized by their large diamond-shaped body with elongated wing-like pectoral fins, ventrally placed gill slits, laterally placed eyes, wide terminal mouths, and paired cephalic lobes (making them the only vertebrate animals with 3 paired appendages).
Manta rays have among the lowest "fecundity" of all elasmobranchs (a subclass of cartilaginous fish), typically giving birth to only one pup every two to three years (or longer in some subpopulations) after reaching maturity at 10 years on average. Gestation is thought to last 10 to 14 months.
Manta spp. are pelagic planktivores. Manta birostris is thought to be a seasonal visitor along productive coastlines with regular upwelling, in oceanic island groups, and near offshore pinnacles and seamounts. They visit cleaning stations on shallow reefs, are sighted feeding at the surface inshore and offshore, and are also occasionally observed in sandy bottom areas and seagrass beds. Manta alfredi are commonly sighted inshore, but are also observed around offshore coral reefs, rocky reefs and seamounts. This species is often resident in or along productive near-shore environments, such as island groups, atolls, or continental coastlines, and may also be associated with areas or events of high primary productivity (e.g., upwelling). Manta birostris has longer migration distances and is more solitary than M. alfredi, though they can aggregate to feed or mate. A possible third species under investigation exhibits similar habitat preferences to M. alfredi.
Manta spp. are global in range, with the two described species overlapping in some locations and not in others. Manta birostris is the more widely distributed, inhabiting tropical, subtropical, and temperate waters, while M. alfredi is found in tropical and subtropical waters. The possible third species appears to not have a global range and to be a regional endemic with a reported distribution throughout the Gulf of Mexico, the Caribbean, and along the eastern coast of the United States.
There are no stock assessments, but regional population sizes are small, and where known, have generally declined except in areas where the species is specifically protected (e.g., Hawaii, Maldives, Yap, Palau).
- targeted fisheries
The prebranchial appendages (or gill plates), which Manta spp. use to filter planktonic food from the water, are highly valued in international trade for use in traditional medicine. Cartilage and skins are also traded internationally while meat is consumed or used for bait locally. A single mature M. birostris can yield up to 15.5 pounds (7 kg) of dried gills that retail for up to $680 per kilo in China.
Manta rays are caught throughout their global warm water range in the Atlantic, Pacific, and Indian Oceans in commercial and artisanal fisheries. Fishermen targeting Manta rays primarily use harpoons and nets, while significant manta bycatch occurs in purse seine, gillnet, and trawl fisheries targeting other species. Alterations to terrestrial ecosystems have also been shown to affect Manta populations. At Palmyra Atoll in the Pacific, a study linked declines in the manta rays' planktonic food source to areas where native trees have been replaced by cultivated palms.
In October 2012, a number of countries agreed to sponsor a proposal to add all manta rays to Appendix II of CITES to provide further protections from the high demand in international trade. The proposal was passed at the CITES meeting in March 2013 and will be effective September 14, 2014.
|CITES Appendix II Proposal||10/04/2012|
- CITES Implementation: U.S. Fish and Wildlife
- IUCN Red List: Manta alfredi
- IUCN Red List: Manta birostris
Updated: August 25, 2014