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The spotted eagle ray (Aetobatus narinari) is a cartilaginous fish belonging to the eagle ray family of stingrays. Its common name comes from its distinctive spots, fins that flap like wings, and protruding snout that resembles an eagle's beak or duck's bill. Usually, the ray is a solitary predator, but it sometimes swims in large groups.
Fast Facts: Spotted Eagle Ray
- Scientific Name: Aetobatus narinari
- Other Names: White-spotted eagle ray, duckbill ray, bonnet ray
- Distinguishing Features: Disk-shaped ray with long tail, blue or black body with white spots, and flat snout resembling a duck bill
- Average Size: Up to 5 m (16 ft) long with wingspan of 3 m (10 ft)
- Diet: Carnivorous
- Life Span: 25 years
- Habitat: Warm coastal water worldwide, although modern classification restricts this species to the Atlantic ocean basin
- Conservation Status: Near threatened
- Kingdom: Animalia
- Phylum: Chordata
- Class: Chondrichthyes
- Order: Myliobatiformes
- Family: Myliobatidae
- Fun Fact: Newborn pups look just like their parents, except much smaller
The ray is easily recognized by its blue or black top dotted with white spots, white belly, and flat "duck bill" snout. There are five small gills on each side of the front half of the belly. The tail is very long and features two to six venomous spines located just behind the pelvic fins. A spotted eagle ray's disk-shaped body can reach 5 meters (6 feet) in length, have a wingspan up to 3 meters (10 feet), and weigh 230 kilograms (507 pounds).In addition to its spots, the spotted eagle ray may be identified by its beak-like snout. Terry Moore/Stocktrek Images / Getty Images
Prior to 2010, the species included spotted eagle rays living in warm coastal waters around the globe. Now the name only refers to the group that lives in the Atlantic, Caribbean, and Gulf of Mexico. The population living in the Indo-West Pacific is the ocellated eagle ray (Aetobatus ocellatus), while the group in the tropical East Pacific Ocean is the Pacific white-spotted eagle ray (Aetobarus laticeps). Only very recent sources make a distinction between the rays, which differ slightly in terms of genetics and morphology. While spotted eagle rays live in coral reefs and protected bays, they may migrate great distances through deep water.This is the historical spotted eagle ray range. Under modern classification, the fish only resides in the Atlantic, Caribbean, and Gulf.
Spotted eagle rays are carnivorous predators that feed upon mollusks, crustaceans, octopuses, and small fish. The rays use their snouts to dig in the sand to expose food, then apply calcified jaws and chevron-shaped teeth to crack open hard shells.
Predators and Parasites
Sharks are the principal predators of spotted eagle rays. Specifically, tiger sharks, lemon sharks, bull sharks, silvertip sharks, and great hammerhead sharks prey upon pups and adults. Humans also hunt rays. Spotted eagle rays host a variety of parasites, including the gnathostomatid nematode Echinocephalus sinensis (in the intestine) and monocotylid monogeneans (on the gills).
Reproduction and Life Cycle
Spotted eagle rays are ovoviviparous or live-bearing. During mating, one or more males pursue a female. The male uses his jaws to grasp the female's pectoral fin and roll her over. When the rays are venter to venter (belly to belly), the male inserts his clasper into the female. The entire mating process takes from 30 to 90 seconds. The female retains the fertilized eggs, which hatch internally and live off the egg yolk. After a gestation period of about a year, the female gives birth to as many as four pups that are miniature versions of their parents. Rays mature in 4 to 6 years and live around 25 years.
Spotted Eagle Rays and Humans
For the most part, spotted eagle rays are shy, gentle creatures that pose no significant threat to humans. The intelligent, curious animals are popular with snorkelers. However, on at least two occasions, leaping rays have landed in boats. One incident resulted in a woman's death in the Florida Keys. Because of their interesting pattern and the graceful way they "fly" through water, spotted eagle rays present a popular aquarium attraction. They have been successfully bred in captivity. Burgers' Zoo in the Netherlands holds the record for the most births.
The spotted eagle ray is "near threatened" in the wild, with a decreasing population trend. However, the latest IUCN evaluation occurred in 2006, which is before the fish was assigned to three separate species. The IUCN categorizes the ocellated eagle ray as vulnerable, while the Pacific white-spotted eagle ray has not been evaluated for conservation status.
From a global perspective, including all three species, threats to the spotted eagle ray include severe population fragmentation, unregulated overfishing, bycatch, pollution, collection for the aquarium trade, and hunting to protect mollusk farms. Fishing pressure presents the most significant threat and is expected to increase. However, there are few portions of the animal's range where the threat is lessened. The spotted eagle ray is protected in Florida and the Maldives and partially protected in Australia.
- Carpenter, Kent E.; Niem, Volker H. (1999). "Batoid fishes". The Living Marine Resources of the Western Central Pacific. Batoid fishes, chimaeras and bony fishes. 3. pp. 1511, 1516. ISBN 92-5-104302-7.
- Kyne, P.M.; Ishihara, H.; Dudley, S. F. J. & White, W. T. (2006). "Aetobatus narinari". The IUCN Red List of Threatened Species. IUCN. 2006: e.T39415A10231645. doi:10.2305/IUCN.UK.2006.RLTS.T39415A10231645.en
- Schluessel, V., Broderick, D., Collin, S.P., Ovenden, J.R. (2010). Evidence for extensive population structure in the white-spotted eagle ray within the Indo-Pacific inferred from mitochondrial gene sequences. Journal of Zoology 281: 46-55.
- Silliman, William R.; Gruber, S.H. (1999). "Behavioral Biology of the Spotted Eagle Ray, Aetobatus narinari (Euphrasen, 1790), in Bimini, Bahamas; an Interim Report".
- White, W.T. (2014): A revised generic arrangement for the eagle ray family Myliobatidae, with definitions for the valid genera. Zootaxa 3860(2): 149-166.