Killarney shad facts for kids
Quick facts for kids Killarney shad |
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|---|---|
| Conservation status | |
| Scientific classification | |
| Genus: |
Alosa
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| Species: |
killarnensis
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The Killarney shad (Alosa killarnensis), also known as the goureen, is a special freshwater fish. It belongs to the Clupeidae family, which includes herrings and sardines. This fish is found only in one place in Ireland: Lough Leane in County Kerry.
Scientists believe the Killarney shad is a type of twait shad (Alosa fallax) that got "landlocked" in the lake. This means it became stuck in the lake and could no longer travel to the sea. This happened after the last Ice Age, about 10,000 years ago. The Killarney shad is now in great danger. The International Union for the Conservation of Nature (IUCN) says it is "critically endangered".
Where the Killarney Shad Lives
The Killarney shad lives only in Lough Leane. This lake is part of the beautiful Killarney National Park in southwestern Ireland. Because it lives in just one place, it is very vulnerable.
The IUCN has listed this fish as "critically endangered". This means it is at a very high risk of disappearing forever. The biggest dangers to the Killarney shad are:
- Eutrophication: This happens when too many nutrients, like from farm runoff, get into the water. This can make the water unhealthy for fish.
- New fish species: Other types of fish, like the common roach and common bream, have been brought into the lake. These new fish might compete with the Killarney shad for food or space.
The Killarney shad is also very sensitive to any kind of pollution in the water.
To help protect these fish, people are working to find where they lay their eggs. They are also trying to keep these special areas safe from water pollution.
Life of the Killarney Shad
The Killarney shad usually lives for about five years. It swims in the open water of the lake to find food. It mainly eats tiny water creatures called zooplankton.
When it's time to lay eggs, usually in June or July, the Killarney shad moves to shallow bays. They like to lay their eggs on gravelly areas and around the lake's islands. Male Killarney shad are usually smaller than the females.
Family Tree and History
Most scientists think the Killarney shad is a unique type of the more common twaite shad. The full scientific name often used is Alosa fallax killarnensis.
Studies of their DNA show that the Killarney shad came from twaite shad. These fish likely arrived in Lough Leane after the ice sheets melted in Ireland, over 10,000 years ago. It seems there might have been two groups of twaite shad that came to the lake and mixed together.
Even though they have been landlocked for a short time, the Killarney shad has changed a lot. They look and act differently from the twaite shad. For example, the Killarney shad is smaller, growing to only about 20 centimeters (8 inches). It also has fewer "gill rakers," which are comb-like structures fish use to filter food from water. Because of these differences, some scientists think it should be considered its own species.
The Killarney shad is the only landlocked type of twaite shad in northwestern Europe. However, there are other landlocked populations of twaite shad in southern Europe.
