As part of our ongoing series of Similan Island Marine Life, Wicked Diving presents:
The Similan Islands are a great place to spot multiple species of any given Fish. That is true for the Rays. Below are three of the most common Rays we see, though this is in no way a complete list More On Manta rays on a separate Page
Dasyatis kuhlii
Kuhl's Bluespotted Ray
Description & Behavior
The bluespotted ray, Dasyatis kuhlii (Müller and Henle, 1841), aka blue spotted stingray, blue-spotted stingray, or blue-spotted maskray, is usually reddish-brown to green with bright blue centered spots (ocelli) and scattered black spots on the dorsal side. The ventral side is white. They have very short, broad, angular snouts and the disc is angular with a total length of 70 cm. The tail is as long as the body with conspicuous black and white rings and a short upper caudal finfold, and longer lower finfold that ends behind the tail tip. There is usually one stinging spine on the tail.
World Range & Habitat
Bluespotted rays are found in the Indo-West Pacific, Red Sea, Zanzibar (Tanzania), South Africa, India, Sri Lanka east to the Philippines, north to Japan, and south to Australia, where it is known from the central coast of Western Australia, around the tropical north and south to the New South Wales north coast. There are a number of different colored morphs in the Indo-Pacific, which may be different species.
The bluespotted ray is a solitary species found on sandy bottoms near rocky or coral reefs. They are usually found in deeper water but are also seen on reef flats and in shallow lagoons at high tide. They are occasionally found covered in sand with just the eyes and tail visible.
Feeding Behavior (Ecology)
The bluespotted ray preys on crabs and shrimps and possibly other small prey.
Life History
The bluespotted ray is an ovoviviparous species. There is a distinct pairing with embrace and pups measure 16 cm at birth.
Ovoviviparous: eggs are retained within the body of the female in a brood chamber where the embryo develops, receiving nourishment from a yolk sac. This is the method of reproduction for the "live-bearing" fishes where pups hatch from egg capsules inside the mother's uterus and are born soon afterwards. Also known as aplacental viviparous.
Comments
The venomous tail spine can inflict a painful wound. They sting only when stepped on, but they are difficult to see since they are often buried in sandy bottoms.
Porcupine Ray
Urogymnus asperrimus
(Bloch & Schneider, 1801) | ||||
| Family: | Dasyatidae (Stingrays) | |||
| Order: | Rajiformes (skates and rays) | |||
| Class: | Elasmobranchii (sharks and rays) | |||
| FishBase name: | Porcupine ray | |||
| Max. size: | 100.0 cm WD (male/unsexed; Ref. 12951) | |||
| Environment: | reef-associated; brackish; marine | |||
| Climate: | tropical; 31°N - 30°S | |||
| Importance: | fisheries: commercial | |||
| Resilience: | Low, minimum population doubling time 4.5 - 14 years (Assuming fecundity<100) | |||
| Distribution: Gazetteer | Indo-Pacific: Red Sea and coast of East Africa to the Marshall Islands and Fiji, south to northern Australia (Ref. 2334). Eastern Atlantic: Senegal, Guinea, and Côte d'Ivoire (Ref. 4438). | |||
| Morphology: | Dorsal spines (total): 0 - 0; Anal spines: 0. A heavily armored stingray lacking a venomous barb; young with large, flat denticles on upper surface, and large juveniles and adults with additional sharp conical thorns and small, pointed denticles (Ref. 5578). Very thick elongated disc with broadly rounded outer corners; snout broadly rounded and tail slender, about as long as body and without finfolds (Ref. 5578). Light grey or whitish dorsally, white ventrally; tail blackish (Ref. 5578). | |||
| Biology: | Inhabits the continental shelf area. Found on sand and coral rubble areas near reefs (Ref. 9840), often in caves. Ovoviviparous (Ref. 50449). Due to its difficult handling, it is probably of limited commercial value (Ref. 9840). | |||
| Red List Status: | Vulnerable (VU) (A1bd, B1+2bcd)(Ref. 57073) | |||
| Dangerous: | traumatogenic | |||
Marbled Ray
Taeniura meyeni
Description & Behavior
The marbled ray, Taeniura meyeni (Müller and Henle, 1841), aka black-blotched stingray, black-spotted stingray, blotched fantail ray, fantail stingray, giant reef ray, round ribbontail ray, and speckled stingray, is a large stingray with a circular disc, no thorns, a black and white mottled upper surface and a deep and prominent ventral skin fold that extends to the tail tip. More widely known as T. melanospila (Bleeker, 1853), a junior synonym based on the description of a juvenile.
Maximum recorded size of 3.3 m and a maximum weight of 150 kg.
World Range & Habitat
Occurs in a wide range of habitats, from shallow lagoons to outer reef slopes. Indo-West Pacific: Red Sea and East Africa to southern Japan, Micronesia, tropical Australia and Lord Howe Island; Eastern Pacific: known only from oceanic islands (Cocos and the Galapagos) but because of sheer number, individuals may colonize Central America coastlines as well.
Found singly or in aggregates and usually with jacks and cobia swimming near them to depths of
up to 500 m.
Feeding Behavior (Ecology)
The marbled ray, Taeniura meyeni, feeds on bottom fish, bivalves, crabs and shrimp.
Life History
The marbled ray is ovoviviparous bearing up to 7 pups in a litter. Distinct pairing with embrace.
Ovoviviparous: eggs are retained within the body of the female in a brood chamber where the embryo develops, receiving nourishment from a yolk sac. This is the method of reproduction for the "live-bearing" fishes where pups hatch from egg capsules inside the mother's uterus and are born soon afterwards. Also known as aplacental viviparous.
Comments
Marbled rays, Taeniura meyeni, are not normally aggressive, but it has been responsible for at least one human fatality. Sought by surf and boat anglers in southern Africa, but usually released unharmed. Longevity record for a specimen in an aquarium is 81 days.
The marbled ray is listed as Vunerable (VU A2ad+3d+4ad) on the IUCN Red List of Threatened Species:
VULNERABLE (VU)
A taxon is Vulnerable when the best available evidence indicates that it meets any of the criteria A to E for Vulnerable, and it is therefore considered to be facing a high risk of extinction in the wild.
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