Western shovelnose stingaree facts for kids
Quick facts for kids Western shovelnose stingaree |
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| Trygonoptera mucosa in Mangles Bay, Australia | |
| Conservation status | |
| Scientific classification | |
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Urolophidae
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| Genus: |
Trygonoptera
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| Species: |
T. mucosa
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| Binomial name | |
| Trygonoptera mucosa (Whitley, 1939)
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| Synonyms | |
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Urolophus mucosus Whitley, 1939 |
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The western shovelnose stingaree (Trygonoptera mucosa) is a common type of stingray. It belongs to the family Urolophidae. This ray lives in shallow, sandy areas and seagrass beds. You can find it off the coast of southwestern Australia, from Perth to Gulf St Vincent.
This small ray can grow up to 37 cm (15 in) long. It has a rounded body, like a disc, and a blunt, wide snout. Its nostrils have special flaps, and there's a fringed curtain of skin between them. The tail is like a spear and has a caudal fin at the end. It does not have dorsal fins or skin folds on its sides. The western shovelnose stingaree is usually grayish or brownish on top. It might have lighter or darker spots. Its underside is pale, sometimes with darker edges.
The main food for this stingaree is polychaete worms. These are worms that live in tubes on the seafloor. It might also eat other small creatures that live on the bottom, and sometimes even small bony fish. Female stingarees give birth to one or two live pups each year. They feed their babies with a special "uterine milk" inside their bodies. The International Union for Conservation of Nature (IUCN) says this species is "Least Concern". This means it is not currently in danger. It is sometimes caught by accident in fishing nets, but usually survives.
Where It Lives
The western shovelnose stingaree lives only in southwestern Australia. It is one of the most common rays in its family there. Its home stretches from Gulf St Vincent near Glenelg to Perth. It might even live further north near Dongara.
This ray lives on the bottom of the ocean. It likes sandy areas and seagrass beds. You can find it in waters from 1–40 m (3.3–131.2 ft) deep. It especially likes deeper waters close to the coast. Young and old stingarees, both males and females, live in the same places all year.
What It Looks Like
The western shovelnose stingaree has a rounded body, called a pectoral fin disc. This disc is a bit wider than it is long. The front edges are almost straight and meet at a wide angle at its snout. The snout is fleshy and blunt.
Its eyes are not very big, but the spiracles behind them are much larger. Spiracles are like breathing holes. The outer edges of its nostrils have large, flat flaps. Between the nostrils, there is a skirt-shaped flap of skin. This flap has a deeply fringed edge and covers its small mouth. The lower jaw has small, nipple-shaped bumps called papillae. There are also 7 to 9 small papillae on the floor of its mouth. Its teeth are tiny and have oval bases. It has five pairs of short gill slits.
The pelvic fins are small and round. The tail is long, about 71–91% of the disc's length. It is flat and oval-shaped. The tail ends in a low, leaf-shaped caudal fin. There is a stinging spine on top of the tail, about halfway along its length. This spine has jagged edges. This ray does not have any dorsal fins or folds of skin on the sides of its tail. Its skin is completely smooth, without any dermal denticles (tiny, tooth-like scales).
The western shovelnose stingaree can be grayish, yellowish-brown, or dark brown on top. Its caudal fin might be dark or black. Some rays have scattered lighter and darker spots. The underside is white or light brown. Sometimes, especially in young rays, there is a wide, dark brown band and spots along the edges of the disc and tail. Males can grow up to 28 cm (11 in) wide, and females up to 37 cm (15 in) wide.
Life Cycle and Diet
The western shovelnose stingaree has larger spiracles than its close relatives. This might mean it is adapted to live in places with less oxygen in the water.
This stingaree mostly eats polychaete worms. These worms make up over 85% of its diet. Most of the polychaetes it eats are the kind that live in buried tubes. The large flaps and many sensory bumps near its mouth probably help it find and pull out these deep-buried worms. It also has a way to avoid eating sediment (sand or mud), possibly by pushing it out through its gill slits. It also eats small amounts of crustaceans like shrimp, amphipods, isopods, and mysids. Sometimes it eats sipunculid worms. It rarely eats Molluscs, echinoderms, or bony fish. Young and old rays eat similar things. However, small rays tend to eat amphipods and tanaids, while large rays eat sipunculids. A parasite that lives on this stingaree is a nematode worm called Echinocephalus overstreeti.
Like other stingrays, the western shovelnose stingaree gives birth to live young. This is called aplacental viviparous reproduction. Adult females have one working uterus (on the left side). They usually have one pup, but sometimes two, every year. Mating and the release of eggs happen in May or June. The newly fertilized eggs are covered by a thin brown membrane. The babies might pause their development for a short time before they start growing.
The babies grow inside the mother for about a year. Once the developing embryos use up their yolk supply, the mother feeds them a special, nutrient-rich liquid. This is called histotroph, or "uterine milk." Birth happens in late May or early June. Newborn rays are about 11 cm (4.3 in) wide. Females grow slower and get bigger than males. Males become ready to have babies when they are about 22 cm (8.7 in) wide and two years old. Females are ready when they are about 25 cm (9.8 in) wide and five years old. Males can live up to 12 years, and females up to 17 years.
Stingarees and People
The western shovelnose stingaree is common. Because of this, it is often caught by accident by fishing boats. These boats are usually fishing for scallops and prawns off Perth and Mandurah. It might also be caught by prawn fisheries in South Australia. This ray is not valuable for food, so it is usually released alive when caught. However, a concern is that stingarees often abort their young (lose their babies) when they are caught.
Even so, most of this species' home range does not have much fishing. Because of this, the International Union for Conservation of Nature (IUCN) has listed it as "Least Concern". This means it is not currently at high risk. This species could benefit from a plan made in 2004 called the Australian National Plan of Action for the Conservation and Management of Sharks.
