The yabbies are a freshwater crustacean endemic to the Southern Hemisphere and a member of the family Parastacidae.
This family may contain as many as 15 different genera. Like crabs, lobsters, prawns, and shrimp, they are classified as decapods. Up to 15,000 species inhabit around 2,700 genera within this massive and varied order.
Cherax destructor is also known as the blue yabby and the cyan yabby. The term “yabby” is also used to refer to a wide variety of different Australian Cherax crustaceans.
How Did Yabbies Evolve With Time?
The yabby is a type of crayfish found in freshwater and thus is classified as a crustacean. The Cambrian Period (about 542 to 488 million years ago) saw the first appearance of this class of aquatic arthropods.
The ostracods were the ancestors of all other members of this group. Over time, other families within this subphylum underwent similar evolutionary changes.
The Palaeopalaemon appeared between 416 and 359.2 million years ago, making it one of the first decapods.
Crayfish ancestry dates back to the Late Permian Period, between 260.4 and 251 million years ago. Many mysteries surround the yabbies and their development that have yet to be solved.
In 2008, researchers found the earliest fossils of crayfish in Australia, dating back to the Mesozoic Era (115 million years ago).
Dinosaur Cove in Victoria, British Columbia, was the site where the evidence was discovered.
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What Does the Yabby Look Like?
The yabby is one of Australia’s largest crayfish species. A carapace, or outer shell, protects the creature’s vital organs. The yabby has three distinct bodily parts: the head, the chest, and the tail.
The rostrum (the area in front of the eyes) is smooth, there are two sets of antennae, and the head has four ridges running from the front to the back.
The swimmerets, which are tiny legs, are paired with two enormous pincers that are linked to the thorax. Different species have slightly different appearances.
However, the claws of most species are wide and spade-shaped. The colouration of these massive pincers often resembles a mesh pattern. The species and environment strongly influence the rest of their body colouration.
The vivid red patch on the claw of the Queensland red claw (Cherax quadricarinatus) is its most distinctive feature.
While the common yabby is typically a shade of blue or cyan, the marron is a deep purple. The vivid colouring of some yabby species makes them desirable aquarium pets.
Their typical tonal palette includes shades of black, blue-black, and dark brown. Brown, beige, and even greenish-brown are all possible colours for certain species. All of them have a flat stomach that’s about as wide as their chests.
Among Australia’s crayfish species, yabbies are some of the largest. Depending on the species, yabbies can range in size from 0.04 to 0.18 pounds and 2.7 to 7.8 inches in length.
Where Do Yabbies Live?
There are freshwater habitats all across the Southern Hemisphere that are home to members of this genus. The most common yabby (Cherax destructor) may be found in many of Australia and New Guinea’s lowland freshwater bodies and is the continent’s most extensively dispersed species.
In the wild, common yabbies may go into aestivation, a state of extended hibernation. When it’s dry, they go into hibernation for a few months in their underground burrows in swamps and muddy rivers.
Cherax crayfish are widespread throughout New Guinea, though they are especially numerous in the Paniai Lakes. New Guinea is home to Cherax acherontis, the only species of cave-dwelling crayfish in the Southern Hemisphere.
The common yabby is notorious for its ability to rapidly multiply, invade new areas, and throw off the local agricultural ecosystem by tunnelling underground.
Due to their striking appearance, certain species are also maintained in aquariums.
Yabbies are the most widely distributed crayfish in Australia, found not just in Victoria and New South Wales but also in southern Queensland, South Australia, large swaths of the Northern Territory, and even down to Tasmania.
As an imported species, it has become a problem in Western Australia, where it threatens native crayfish such as the gilgie (Cherax quinquecarinatus).
Yabbies inhabit low to medium-altitude wetlands, waterways, reservoirs, and farm dams.
Before European arrival, yabbies were likely present only in lower-altitude habitats in the Murray-Darling Basin and other inland regions of south-eastern Australia, whereas the Euastacus spiny crayfish species inhabited higher-altitude habitats and the coastal river systems.
Lakes Eucumbene and Jindabyne, located on the upper parts of the coastal Snowy River system, are home to a peculiar group of yabbies: high-altitude yabbies.
What Do Yabbies Eat?
Yabbies are scavengers or detrivores. They consume anything they come upon in the water, including:
- Decaying vegetation
- Algae
- Small fish
- Frog eggs
- Worms, etc.
They use their enormous pincers to scoop food up to their mouths. The yabby has been known to assault and consume its own kind.
Bigger yabbies frequently attack and eat juveniles and adults whose bodies are still pliable after moulting.
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What Eats Yabbies?
Barring extreme circumstances, a yabby can live for up to five years in the wild. This crustacean’s natural enemies consist of:
- Other yabbies
- Humans
- Birds
- Insects
- Water birds
- Callop
- Murray cod
- Gudgeons
- Goldfish
- Water beetles
- Backswimmers
- Dragonfly nymphs
What is Yabbying?
Children and adults alike in Australia enjoy “yabbying” (the act of catching yabbies) in the summers in rivers and agricultural dams.
The most common technique is to throw a piece of meat into the water after first attaching it to a few meters of string or fishing line, which is then attached to a stick in the bank.
When a yabby tries to steal the meat, it clenches its claws around it and pulls the string tight. In most cases, the yabby will cling to the meat as the line is carefully retrieved back to the bank.
When the meat and the yabby reach the water’s edge, a net is utilized to rapidly and efficiently capture both the meat and the yabby.
Yabbies can also be caught using a variety of nets and traps.
Because of the risk of entanglement and drowning for animals like platypus, water rats, and long-necked turtles, it is important to check local fishing regulations before attempting to catch yabbies with nets or traps.
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Conclusion
The yabby is the most widely distributed species of crayfish in Australia, and it is a fully aquatic freshwater crayfish.
Yabby, which belongs to the genus Cherax, are found in the slow-moving streams of Australia and New Guinea. It has a special adaptation that permits it to survive in harsh environments without water.
Damage to agricultural dams and levee bank walls has been reported from various species in this genus.
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