Murray crayfish facts for kids
Quick facts for kids Murray crayfish |
|
|---|---|
.jpg) |
|
| Conservation status | |
| Scientific classification |
The Murray crayfish (scientific name: Euastacus armatus) is a special type of freshwater crayfish. It lives only in Australia, which means it's endemic there. This amazing creature belongs to a family of crayfish called Parastacidae.
You can find Murray crayfish in the Murray and Murrumbidgee Rivers. They also live in many smaller rivers and streams that flow into these big rivers. They have the biggest natural living area of all Euastacus crayfish in Australia. People call them by many names, like "Murray River crayfish," "Murray crays," or "spinies." In some places, like Wagga Wagga, they are even called "lobsters"!
Contents
About the Murray Crayfish
What Does It Look Like?
Adult Murray crayfish usually grow to be about 20 to 30 centimeters (8 to 12 inches) long. But in the past, some really big ones were found! They could weigh up to 2 kilograms (4.4 pounds). This makes the Murray crayfish the second largest freshwater crayfish in the world. Only the Tasmanian giant freshwater crayfish is bigger.
Murray crayfish have big, white claws. Their main body, called a carapace, is dark olive, grey, or black. Both their claws and body are covered in short, strong spikes. When they are young, their claws are often green and yellow.
Where Do They Live?
Murray crayfish like cool, fast-flowing water. They prefer deep pools and riverbeds with lots of rocks and boulders. They also like areas with many plants along the riverbanks.
Historically, these crayfish lived all over the southern Murray–Darling basin. This is a huge river system in Australia. Today, you won't find them in the Murray River downstream of Mildura. This change is due to too much fishing and changes in their environment. They can live in streams high up in the mountains, over 700 meters (2,300 feet) above sea level. They also live in lower areas of the Murray and Murrumbidgee Rivers.
Life Cycle and Diet
Murray crayfish start to breed when they are about 15 to 20 centimeters (6 to 8 inches) long. It takes them between 6 and 9 years to reach this size. In late autumn, female crayfish lay between 500 and 1,000 eggs. They carry these eggs under their tails, attached to special swimmerets called pleopods. The eggs stay there until they hatch in the summer.
These crayfish mostly eat decaying aquatic plants. This means they munch on dead or rotting plants that are in the water. They will also eat dead animals they find.
Why Are They in Danger?
The Murray crayfish is facing some threats. One big problem is overfishing. This means too many crayfish are being caught. Because of this, there are special rules for people who fish for them. These rules are different in each state, like New South Wales and Victoria.
The rules often include:
- A minimum size for crayfish you can keep.
- Limits on how many crayfish you can catch (bag limits).
- Limits on how many you can have with you (possession limits).
- A ban on taking female crayfish that are carrying eggs.
- A limited season for fishing, usually from the start of May to the end of August.
Another threat is habitat loss. This means the places where they live are disappearing or changing. For example, in one river, the Goobarragandra River, the number of Murray crayfish dropped by 91% in just six years. This happened because their preferred rocky habitats were covered by mud and sand.
The Murray crayfish is listed as "Data Deficient" on the IUCN Red List. This means we don't have enough information to know exactly how threatened they are globally. However, they are listed as "vulnerable" in the Australian Capital Territory. They are also considered "endangered" in South Australia.
