Philippines spurdog facts for kids
Quick facts for kids Philippines spurdog |
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| S. montalbani from the original description of the species in 1912. | |
| Conservation status | |
| Scientific classification | |
| Genus: |
Squalus
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| Species: |
montalbani
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| Synonyms | |
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Squalus philippinus Smith and Radcliffe 1912 (see text) |
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The Philippines spurdog (Squalus montalbani) is a type of dogfish shark. It is also known as the Indonesian greeneye spurdog. This shark lives in the waters near Australia, the Philippines, and Indonesia.
Scientists first found this shark in 1912 near Luzon Island. People have caught it for food and by accident ever since. Its name and classification have been a bit confusing over the years. In 2007, scientists finally confirmed it as its own species again.
The International Union for Conservation of Nature (IUCN) says this shark is "vulnerable." This means its numbers are decreasing because of fishing. It looks very much like other sharks, which makes it hard to count them. This also makes it harder to protect them.
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What Does the Philippines Spurdog Look Like?
The Philippines spurdog is a fairly large dogfish shark. Female sharks can grow up to about 94.5 centimeters (37 inches) long. Males are a bit smaller, reaching about 84.0 centimeters (33 inches). Like other sharks in its group, it has small spines on its back fins.
Its colors are similar to other sharks in its group. Its back is light grey, and its belly is white. It has a dark bar on its tail fin, called a caudal bar. This bar is dark and almost straight up and down. The caudal bar on the Philippines spurdog is longer than on some other similar sharks. This helps scientists tell them apart. It also has a dark spot on the top part of its tail fin. The shape and place of this spot are also different from other sharks.
Like most sharks, the Philippines spurdog gives birth to live young. The pups grow inside the mother using a yolk sac for food. Scientists have seen mothers with 4 to 16 pups at a time.
These sharks mostly eat small fish, squid, and crabs.
How Did the Philippines Spurdog Get Its Name?
The Philippines spurdog was first described in 1912. The scientists named it S. philippinus. But this name had already been used for a different shark, the Port Jackson shark. So, the name S. philippinus could not be used for the Philippines spurdog.
In 1931, a scientist named Gilbert Percy Whitley gave it a new name: S. montalbani. For a while, some scientists thought it was the same as another shark, S. mitsukurii. This was because they looked very similar and lived in the same areas.
However, in 2007, after more study, scientists confirmed that S. montalbani was its own species. They looked closely at its body shape and color patterns to see the differences.
The very first Philippines spurdog specimen was collected in 1908. It was a young male found deep in the ocean near Sombrero Island in the Philippines. This first specimen is kept at the Museum of Natural History.
Where Does the Philippines Spurdog Live?
The Philippines spurdog lives only in the ocean. You can find it in the Pacific Ocean and eastern Indian Ocean. It lives near SE Asia, the Philippines, and Australia. In Australia, it is often found off the coasts of New South Wales, Queensland, and Western Australia. It also lives all over the waters of the Philippines and Indonesia.
This shark prefers warm to mild waters. It usually lives in deep parts of the ocean, close to the bottom. Scientists have found these sharks as deep as 1,370 meters (4,495 feet). They have also been found as shallow as 154 meters (505 feet). But they are most often caught between 383 and 670 meters (1,257 to 2,198 feet) deep. They are found along the edges of continents or near islands.
Why is the Philippines Spurdog in Danger?
People fish for the Philippines spurdog in Indonesia. They use long lines with many hooks. Sometimes it is caught on purpose, and sometimes it is caught by accident while fishing for other sharks. People eat this shark. Its fins and liver oil are also valuable.
In the 1990s, there was a short period of fishing for this shark in Australia. But the number of sharks caught dropped very quickly. Because of this, the fishery closed in 1999.
The IUCN listed the Philippines spurdog as "vulnerable" in 2008. This means it is at risk because of fishing. It is hard to protect this shark because it looks so much like other sharks. This makes it difficult to know exactly how many there are.
Records show that other similar dogfish sharks in Australia saw a huge drop in numbers in the 1970s. Some populations in New South Wales may have decreased by as much as 97% due to fishing. The IUCN believes the total number of Philippines spurdog sharks has dropped by more than 30% from its original levels. Their population is still decreasing.
