Titicaca orestias facts for kids
Quick facts for kids Titicaca orestias |
|
|---|---|
 |
|
| Conservation status | |
| Scientific classification | |
| Synonyms | |
|
Orestias humboldi |
The Titicaca orestias (Orestias cuvieri), also known as the amanto, was a type of freshwater fish. It lived in Lake Titicaca in South America. This fish is likely extinct, meaning it has probably died out. It belonged to a group of fish called Orestias. These fish are special because they only live in lakes and rivers in the high Andean mountains.
The Titicaca orestias was the biggest fish in its group. It could grow up to 27 centimeters (about 10.6 inches) long. Scientists hope some might still be alive. So, it is listed as 'Data Deficient' by a group called IUCN. Even though it's called the 'Titicaca orestias', it wasn't the only Orestias fish in Lake Titicaca.
This fish had a mouth that pointed almost upwards. This made its flat head look a bit like a bowl. Its head was nearly one-third of its total body length. The top part of the fish was greenish-yellow to dark brown. Its lower jaw was black. The scales on its body were light in the middle. Young fish had scales with blotches.
The Titicaca orestias likely died out because of new fish brought into the lake. These included lake trout, brown trout, rainbow trout, and Argentinian silverside. These new fish were introduced between the 1930s and 1950s. A study in 1962 could not find any Titicaca orestias.
Contents
About the Titicaca Orestias
The Orestias cuvieri is a type of killifish. It belongs to the Orestias group of fish. Many other related Orestias species live in the same area. They form a special group called a species flock.
Fish Body and Features
The Titicaca orestias had unique patterns of tiny holes on its head. It had large, thick scales along its back ridge. Smaller, thinner scales were around this ridge. Some areas of its skin had no scales at all. Unlike most other Orestias species, adult O. cuvieri had bumpy scales. Its bowl-shaped body and jaw also helped tell it apart from other Orestias fish.
Scientists noticed that the body of O. cuvieri looked a lot like the trout now found in Lake Titicaca. This similarity makes many researchers think that the trout competed with O. cuvieri. This competition might have caused the O. cuvieri's extinction.
Size of the Fish
Different Orestias species have different sizes. The Titicaca orestias was the largest fish in its group. The biggest one ever recorded was 22 centimeters (8.7 inches) long from snout to tail fin. Its total length, including the tail, was 27 centimeters (10.6 inches). This is much larger than most other species. Only O. pentlandii comes close, growing up to 20 centimeters (7.9 inches) in standard length and 23.5 centimeters (9.3 inches) in total length.
Colors and Markings
The amanto fish had black spots called melanophores on its sides. These formed a band along its side line. There were also small groups of spots on its upper sides. Tiny melanophores covered its fins, making them look grayish. This grayish color faded to white on its back and belly. Young fish had similar color patterns that stayed mostly the same in adult males and females. So, the color of the Titicaca orestias depended on which part of its body you looked at.
Life Cycle
Reproduction
Scientists have not published much about how the Titicaca orestias reproduced. However, in other Orestias species from Lake Titicaca, males become more orange or yellow when they are ready to lay eggs. During this time, females lay between 50 and 400 eggs. Each egg is yellowish and about 2.5 millimeters (0.1 inches) wide. To protect them from the sun, the eggs develop a black protective layer. This layer comes from special cells called melanophores.
Ecology
Where They Lived and Their Home
Freshwater fish from the Orestias group live in high-altitude lakes. These lakes are found in the Altiplano region of South America, from Peru to Chile. Lake Titicaca, located on the border of Peru and Bolivia, has many different Orestias fish. This large lake was once home to Orestias cuvieri before they died out.
Population and What They Ate
At one time, Lake Titicaca had about 30 native fish species. Out of these, 28 belonged to the Orestias group. In the mid-1900s, people tried to bring new types of fish into the lake. Two of these new fish were successful: rainbow trout, brought in 1942, and silverside (Odontesthes bonariensis), brought in the early 1950s.
The success of the silverside fish led to the decline of the Titicaca orestias. People saw that the larger silversides would eat the amanto. As long as the silverside fish did well, it was hard for the amanto to survive. Fifty years ago, there were no signs of Orestias cuvieri in Lake Titicaca. The species was then thought to be extinct.
O. cuvieri mainly ate smaller fish.
Human Impact
Since the Miocene era, Orestias species have lived mostly by themselves. Most water areas in the Altiplano region are endorheic. This means they are closed off and do not let any water flow out. So, Orestias fish have stayed in their own water basins. Each group of fish is specially suited to the unique basin where it lives. Any change to the water would greatly affect the fish.
When humans brought foreign fish into the Altiplano basins, it had bad results. The new species competed with Orestias cuvieri and ate them. This eventually led to the extinction of the Titicaca orestias.
Pollution also harms the water. Traces of metals, like zinc and copper, have been found in fish bodies. Also, water running off from farms, carrying fertilizers and pesticides, has been very harmful to the fish. People also take a lot of water from the Altiplano region. This reduces the amount of water in the Orestias' homes. All these human actions have badly affected the health and survival of different Orestias species, especially O. cuvieri. So, the extinction of the Titicaca orestias was largely caused by humans.
Conservation Efforts
Law Enforcement
To protect fish, more effort is needed to stop pollution and illegal fishing. These efforts are especially important in the area of Lake Titicaca, between Peru and Bolivia. The O. cuvieri is likely already extinct. Other native species, like the suche (Trichomycterus rivulatus), boga (O. pentlandii), yellow karachi (O. albus), and ispi (O. ispi), are also in danger. This is due to too much fishing, being eaten by new species, and the effects of large trout farms.
It is hard to enforce these laws because Lake Titicaca is so big. Law enforcement should look out for long casting, where very long fishing lines are used. These lines can catch fish that are not meant to be caught. Even more important, law enforcement should watch out for pollution.
Museum Specimens
The National Museum of Natural History in the Netherlands, Naturalis, has several specimens of the Titicaca orestias. Two of these were given by the Zoological Museum at Heidelberg University in 1877. One more was given in 1880 from the Smithsonian Institution. Also, four specimens, labeled "Orestias humboldi", were given by the Muséum national d'histoire naturelle in France.
Related Species
Scientists have found 43 species in the Orestias group. An American fish expert, Lynne R. Parenti, divided these species into four groups in 1984. In 2003, Arne Lüssen studied the phylogeny (how species are related). He looked at the DNA of many species. The Lake Titicaca orestias, O. cuvieri, is part of the cuvieri species complex. This group also includes O. forgeti, O. ispi, and O. pentlandii.
See also
In Spanish: Boga del lago Titicaca para niños
