Round stingray | |
---|---|
Urobatis halleri | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Chondrichthyes |
Subclass: | Elasmobranchii |
Order: | Myliobatiformes |
Family: | Urotrygonidae |
Genus: | Urobatis |
Species: | U. halleri |
Binomial name | |
Urobatis halleri J. G. Cooper, 1863 | |
Range of the round stingray | |
Synonyms | |
Urolophus halleriCooper, 1863 Contents |
The round stingray (Urobatis halleri) or Haller's round ray and Little round stingray is a species of round ray, family Urotrygonidae, found in the coastal waters of the tropical and subtropical parts of the northeastern Pacific Ocean. It is a small, common ray that feeds mostly on benthic invertebrates. On the beaches of southern California, it is responsible for numerous injuries to bathers, who are stung when they accidentally step on the fish. The wound caused by its venomous spine can be painful, but is non-fatal.
The species name, halleri, is after the young son of Major Granville O. Haller of the United States Army, who was stung on the foot while wading along the shores of San Diego Bay. [2]
This species is endemic to the eastern North Pacific Ocean, from Humboldt Bay in northern California south to Panama. It is most common around southern California and the Baja Peninsula. They inhabit tropical to warm-temperate waters close to shore, usually less than 15 m deep, although they have been reported to a depth of at least 91 m. This species favors soft-bottomed habitats such as mud or sand, often with abundant eelgrass, which they use for camouflage. [2] [3] They also occur around rocky reefs. [3]
Round stingrays prefer temperatures above 10 °C (50 °F); the adults are more tolerant of temperature changes than juveniles. They are most abundant in the coastal and bay waters of southern California from spring to fall. In winter, they move to deeper water where the temperature is more stable. [2] Round stingrays have been observed congregating near the warm seawater effluent released by coastal electric generators, which may replicate the conditions of estuary environments. [4]
The round stingray has a nearly round pectoral fin disc usually colored brown or grayish brown above, with pale yellow spots or reticulations. Some individuals are plain or black. The underside is white to yellowish. The tail is short and stout, with a long, thick, serrated stinging spine. The teeth are small and diamond-shaped, and sexually dimorphic in that the central teeth of males are erect, sharply pointed, and curved inward. They attain a maximum pectoral fin disc width of 25 cm in males and 31 cm in females. [2]
The tail spine is periodically shed and replaced; for most of the year round stingrays have only one spine, but at the beginning of July small secondary spines begin to appear. The number of rays with secondary spines increases to a peak around September and October, then declines as the primary spines fall off and are replaced. The replacement process is complete by December. [5]
In nature, round stingrays strongly segregate by age and sex, with the females staying in water deeper than 14 m and males and juveniles in shallower habitat. The juveniles feed on polychaete worms and small benthic crabs until they are 14 cm across. As they mature, their diet shifts towards bivalve molluscs. Round stingrays are daytime foragers that are most active in the warm temperatures of summer and fall. Using their pectoral disc and mouths, they dig large pits to uncover buried prey. The digging of these pits plays an ecologically important role, as they also uncover prey for smaller fish. [2]
In the northern part of its range, round stingrays are preyed upon by the northern elephant seal and the giant sea bass. Other predators include large sharks. Numerous parasites are known for the round stingray, comprising 40 species in approximately 19 families. External parasites include copepods and leeches, while 16 species of tapeworms are known from its digestive system, including Phyllobothrium hallericola n. sp. and Acanthobothrium olseni. Additional parasites that may be found in this ray's spiral valve intestine include Eimeria chollaensis sp. nov. and Rhinebothrium spp. [6]
As with other stingrays, the round stingray reproduces through aplacental viviparity, bearing litters of 1–6 young with an average of 2–3. The litter size increases with female size. The gestation period is three months, with the young measuring 6–8 cm across at birth. The females are able to store sperm year-round. In southern California, the females move inshore to mate from April to June, with the young being born between June and October. Further south in the Gulf of California, females mate and give birth earlier, from late winter to spring. A portion of the population mate and give birth in winter, allowing for a second breeding season later that same year. After giving birth, the adult females move back into deeper water while the young remain in the shallows. [2] Female round stingrays emit a localized positive electric field from near the spiracles behind each eye, which serves to attract males. The males will bite at the area, with successful contact necessary for copulation. [6] Round stingrays grow at 3 cm per year until they reach maturity at around 31 months, at which time their growth rate slows. [2]
Every year, hundreds of beachgoers are accidentally stung by round stingrays along the coast of southern California. The sting is not fatal, though it is quite painful. The so-called "Ray Bay" at the northern end of Seal Beach, used as a nursery ground by round stingrays, is the most notorious location for these incidents. [5]
Due to its small size and large tail spine, the round stingray is considered commercially undesirable. It is occasionally caught (and discarded) by recreational anglers and artisanal gillnet fisheries. In Mexico, the tail is usually cleaved off before the ray is discarded, likely causing high mortality. [1] This species is also taken as bycatch by shrimp trawlers, who consider them a nuisance as large groups often become entangled in the nets. [2] Due to its abundance and relatively high rate of reproduction, the round stingray is assessed as of Least Concern on the IUCN Red List. [1]
Round stingrays frequently make their way into the aquarium trade and are well suited for captive life given their relatively small size and hardiness (if provided with a proper environment). An aquarium with very little aquascaping (rocks, decorations, etc.), a bed of fine substrate (fine sand as opposed to coarse sand and gravel), adequate filtration (given the messy feeding habits of rays), a secure lid or cover, much swimming area (long, wide tanks as opposed to tall, skinny ones), dim lighting, linear flow (aka. constant not chaotic flow), a total flow rate of 10+ the tank's volume per hour moving in a fashion similar to that of a whirl pool (with no areas of low flow in the tank), and a water temperature of in between 12 °C (53.6 °F) and 22 °C (71.6 °F) is suitable for this ray. Additionally, any protruding equipment in the aquarium like overflows should be surrounded by polyurethane foam barriers to prevent injury towards the ray and dissolved oxygen levels should be maintained at 7–8ppm (slightly more if ozone is used). Stray electrical currents and concentrations of metal in the tank water should be avoided meaning that copper should not be used as medicine on this ray. Feeding should be done with a feeding stick or long forceps seven times a week (preferably with food that does not contain thiaminase) to ensure the ray eats what is intended for it. Small individuals should be fed non fibrous foods like frozen Mysid shrimp, live Brine shrimp and Blackworms, and finely chopped Shrimp. Iodine should also be administered through water changes and/or Elasmobranch vitamins. If it is not administered, this ray can develop Goitre. [7] [8]
Unhealthy individuals will lose weight and have a seemingly hollow abdomen, become lethargic, have faded markings, and they will take on a light shade of gray. These individuals should not be purchased. When first introduced to a tank, Round stingrays may fast for a period of time. A good food source to get them eating is live food including Grass shrimp. After living within aquarium confines for a period of time, they will become relatively tame. Tankmates that should be avoided are Scorpionfish, Butterflyfish, large Angelfish (Pygoplites/Pomacanthus/Holacanthus), Filefish, Triggerfish, Pufferfish, Porcupinefish, certain Sharks (Ginglymostomatidae/Orectolobidae), large Crabs, Hermit crabs, and Sea anemones. These can all irritate or lead to the demise of a Round stingray in an aquarium. Round stingrays may also rest on top of/ knock over Corals which may sting the ray or get damaged so it is a poor choice for a Reef aquarium even though they do not consume corals. As a juvenile, the ray is also vulnerable to being consumed by Frogfish and large Groupers. [7]
The Round stingray is most often collected from California's southern coast [7] and this is probably how the Round stingray has earned the name California stingray in the aquarium trade [9] [ citation needed ]. It also goes by several other names in the hobby including the Spotted stingray, Cortez ray, and Dwarf cortez ray.[ citation needed ] When it is sold under the last two names, it is often misidentified with the very similar Cortez round stingray (Urobatis maculatus).[ citation needed ] The two can be told apart because the Round stingray lacks the black spots the Cortez round stingray has on either side of its disk. [6]
Round stingrays are also kept in some Public aquariums including the Aquarium of the Pacific [10] in Long Beach, California where their tail spines are clipped off periodically so they are safe to touch until they grow back.[ citation needed ]
Stingrays are a group of sea rays, a type of cartilaginous fish. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae, Plesiobatidae, Urolophidae (stingarees), Urotrygonidae, Dasyatidae, Potamotrygonidae, Gymnuridae and Myliobatidae . There are about 220 known stingray species organized into 29 genera.
The Urolophidae are a family of rays in the order Myliobatiformes, commonly known as stingarees or round stingrays. This family formerly included the genera Urobatis and Urotrygon of the Americas, which are presently recognized as forming their own family Urotrygonidae. Stingarees are found in the Indo-Pacific region, with the greatest diversity off Australia. They are sluggish, bottom-dwelling fish that have been recorded from shallow waters close to shore to deep waters over the upper continental slope. Measuring between 15 and 80 cm long, these rays have oval to diamond-shaped pectoral fin discs and relatively short tails that terminate in leaf-shaped caudal fins, and may also have small dorsal fins and lateral skin folds. Most are smooth-skinned, and some have ornate dorsal color patterns.
The horn shark is a species of bullhead shark, in the family Heterodontidae. It is endemic to the coastal waters off the western coast of North America, from California to the Gulf of California. Young sharks are segregated spatially from the adults, with the former preferring deeper sandy flats and the latter preferring shallower rocky reefs or algal beds. A small species typically measuring 1 m (3.3 ft) in length, the horn shark can be recognized by a short, blunt head with ridges over its eyes, two high dorsal fins with large spines, and a brown or gray coloration with many small dark spots.
The round ribbontail ray or blotched fantail ray, is a species of stingray in the family Dasyatidae, found throughout the nearshore waters of the tropical Indo-Pacific, as well as off islands in the eastern Pacific. It is a bottom-dwelling inhabitant of lagoons, estuaries, and reefs, generally at a depth of 20–60 m (66–197 ft). Reaching 1.8 m (5.9 ft) across, this large ray is characterized by a thick, rounded pectoral fin disc covered by small tubercles on top, and a relatively short tail bearing a deep ventral fin fold. In addition, it has a variable but distinctive light and dark mottled pattern on its upper surface, and a black tail.
The bluespotted ribbontail ray is a species of stingray in the family Dasyatidae. Found from the intertidal zone to a depth of 30 m (100 ft), this species is common throughout the tropical Indian and western Pacific Oceans in nearshore, coral reef-associated habitats. It is a fairly small ray, not exceeding 35 cm (14 in) in width, with a mostly smooth, oval pectoral fin disc, large protruding eyes, and a relatively short and thick tail with a deep fin fold underneath. It can be easily identified by its striking color pattern of many electric blue spots on a yellowish background, with a pair of blue stripes on the tail.
The Atlantic stingray is a species of stingray in the family Dasyatidae, common along the Atlantic coast of North America from Chesapeake Bay to Mexico, including brackish and freshwater habitats. It may be distinguished from other stingrays in the area by its relatively elongated snout. This species is of little commercial importance, other than for sale in the aquarium industry.
The pelagic stingray is a species of stingray in the family Dasyatidae, and the sole member of its genus. It is characterized by the wedge-like shape of its pectoral fin disc, which is much wider than long, as well as by the pointed teeth in both sexes, whip-like tail with extremely long tail spine, and uniform violet to blue-green coloration. It generally reaches 59 cm (23 in) in width. The pelagic stingray has a worldwide distribution in waters warmer than 19 °C (66 °F), and migrates seasonally to spend the summer closer to the continental shelf and at higher latitudes. The only stingray that almost exclusively inhabits the open ocean, this species is typically found in surface waters down to a depth of 100 m (330 ft). As a consequence of its midwater habits, its swimming style has evolved to feature more of a flapping motion of the pectoral fins, as opposed to the disc margin undulations used by other, bottom-dwelling stingrays.
The longnose stingray is a species of stingray in the family Dasyatidae, native to the western Atlantic Ocean from the southern Gulf of Mexico to Brazil. Found in coastal waters no deeper than 36 m (118 ft), this demersal species favors muddy or sandy habitats. The longnose stingray is characterized by its angular, rhomboid pectoral fin disc, moderately projecting snout, and whip-like tail with a dorsal keel and ventral fin fold. It typically grows to 1.25 m (4.1 ft) across and is brownish above and light-colored below.
The common stingaree is a species of stingray in the family Urolophidae. The most abundant ray in inshore waters off eastern Australia, it generally inhabits estuaries, sandy flats, and rocky reefs from the shore to a depth of 60 m (200 ft). This plain brownish to grayish species has a rounded pectoral fin disc with a broadly triangular snout. Its nostrils have enlarged lobes on their outer margins and a skirt-shaped curtain of skin with a fringed posterior margin between them. Its tail bears a small dorsal fin before the stinging spine, and terminates in a leaf-shaped caudal fin. This ray can grow to 52 cm (20 in) long.
The bullseye round stingray, also known as the reticulated round ray, or spot-on-spot round ray, is a species of cartilaginous fish in the family Urotrygonidae. It is endemic to Mexico. Its natural habitats are shallow seas, subtidal aquatic beds, coral reefs, estuarine waters, intertidal marshes, and coastal saline lagoons. It is threatened by habitat loss.
The yellow stingray is a species of stingray in the family Urotrygonidae, found in the tropical western Atlantic Ocean from North Carolina to Trinidad. This bottom-dwelling species inhabits sandy, muddy, or seagrass bottoms in shallow inshore waters, commonly near coral reefs.
Urobatis maculatus, known as the spotted round ray or Cortez round stingray, is a species of round ray, within the genus Urobatis, and of the family Urotrygonidae. It is endemic to Mexico, with its natural habitats being shallow seas, subtidal aquatic beds, coral reefs, estuarine waters, intertidal marshes, and coastal saline lagoons.
The spotted stingaree is an uncommon species of stingray in the family Urolophidae, endemic to shallow waters along the coast of southern Australia. It favors rocky reefs and seagrass beds. This species can be readily identified by its nearly circular, dark-colored pectoral fin disc, adorned with a complex pattern of white or cream spots. Its eastern and western forms differ slightly in coloration and have been regarded as separate species. There is a skirt-shaped curtain of skin between its nostrils. Its tail is fairly thick and terminates in a short leaf-shaped caudal fin; a relatively large dorsal fin is present just in front of the stinging spine.
The lined seahorse, northern seahorse or spotted seahorse, is a species of fish that belongs to the family Syngnathidae. H. erectus is a diurnal species with an approximate length of 15 cm and lifespan of one to four years. The H. erectus species can be found in myriad colors, from greys and blacks to reds, greens, and oranges. The lined seahorse lives in the western Atlantic Ocean as far north as Canada and as far south as the Caribbean, Mexico, and Venezuela. It swims in an erect position and uses its dorsal and pectoral fins for guidance while swimming.
The common stingray is a species of stingray in the family Dasyatidae, found in the northeastern Atlantic Ocean and the Mediterranean and Black Seas. It typically inhabits sandy or muddy habitats in coastal waters shallower than 60 m (200 ft), often burying itself in sediment. Usually measuring 45 cm (18 in) across, the common stingray has a diamond-shaped pectoral fin disc slightly wider than long, and a whip-like tail with upper and lower fin folds. It can be identified by its plain coloration and mostly smooth skin, except for a row of tubercles along the midline of the back in the largest individuals.
The reticulate whipray or honeycomb stingray is a species of stingray in the family Dasyatidae. It inhabits coastal waters in the western Indian Ocean including the Red Sea, Natal and the Arabian Sea; also a Lessepsian transmigrant in the eastern Mediterranean. A large species reaching 2 m (6.6 ft) in width, the reticulate whipray has a diamond-shaped pectoral fin disc and an extremely long tail without fin folds. Both its common and scientific names refer to its ornate dorsal color pattern of many small, close-set dark spots or reticulations on a lighter background. However, the reticulate whipray is only one of several large spotted stingrays in the Indo-Pacific which, coupled with the variability of its coloration with age and locality, has resulted in a great deal of taxonomic confusion.
The brown whipray is a species of stingray in the family Dasyatidae, common in inshore, muddy habitats along the northern coast of Australia. It has often been confused in literature for the honeycomb stingray and the black-spotted whipray, which until recently was thought to be the same species. This species has an angular, diamond-shaped pectoral fin disc and a long, very thin tail without fin folds. It is plain brown above, sometimes with white dots or flecks near the edge of the disc, and white below; the tail is dark all over, with alternating dark and light bands near the tip. The maximum recorded disc width is 74 cm (29 in).
The leopard round stingray or Central American round stingray and Costa Rican round stingray is a small species of round ray found in shallow waters off the coast from Costa Rica to Colombia in the eastern Pacific Ocean.