Queensland lungfish facts for kids
Quick facts for kids Queensland lungfish |
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The Australian lungfish (Neoceratodus forsteri) is a very special fish. It is also called the Queensland lungfish, Burnett salmon, or barramunda. This fish is the only one left in its ancient family, the Neoceratodontidae. It is one of only six types of lungfish still alive in the world today.
This amazing fish lives only in Australia. Its family, the Neoceratodontidae, is very old. They are part of a group called lobe-finned fishes. Scientists have found fossils of this group from 380 million years ago. This was around the time when many higher animals with backbones started to appear.
Fossils of lungfish that look almost exactly like the Australian lungfish have been found in New South Wales. This shows that the Neoceratodus has not changed much for over 100 million years! This makes it a "living fossil" and one of the oldest living animals with a backbone on Earth.
The Australian lungfish is one of six types of ancient, air-breathing lungfish. These fish were common during the Devonian period, about 413 to 365 million years ago. The other five types of freshwater lungfish live in Africa (four types) and South America (one type). They look very different from the Australian lungfish. The Queensland lungfish can live for several days out of water if it stays wet. However, it cannot survive if its water completely dries up, unlike some African lungfish.
The town of Ceratodus in Queensland got its name from the Australian lungfish. The fish was named by Gerard Krefft to honor William Forster, a politician.
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Where the Australian Lungfish Lives
The Australian lungfish naturally lives only in the Mary and Burnett River systems in south-eastern Queensland. Over the last 100 years, people have successfully moved them to other rivers further south. These include the Brisbane, Albert, Stanley, and Coomera Rivers. They also live in the Enoggera Reservoir.
Australian lungfish have also been put into the Pine, Caboolture, and Condamine Rivers. But we don't know if they are still alive and breeding there. Long ago, there were at least seven types of lungfish in Australia.
This fish likes to live in slow-moving rivers and calm water, like reservoirs. These places usually have some plants growing along the banks. They live on bottoms made of mud, sand, or gravel. Australian lungfish are often found in deep pools, about 3 to 10 meters (10 to 33 feet) deep. They live in small groups under sunken logs, in thick groups of water plants, or in underwater caves. These caves are formed when soil washes away under tree roots on river banks. The lungfish can handle cold water, but they prefer water temperatures between 15 and 25 degrees Celsius (59 to 77 degrees Fahrenheit).
The Australian lungfish cannot survive if its home completely dries out. But it can live out of water for several days if its skin stays wet. Unlike the African lungfish, it does not bury itself in the mud and create a slimy cocoon to survive dry seasons.
The Australian lungfish usually stays in one place. It spends its life in a small area, often just one pool or two pools next to each other. It does not travel far. However, it might look for good places to lay eggs between July and December.
What the Australian Lungfish Looks Like
Australian lungfish are olive-green to dull brown on their backs, sides, tails, and fins. Their undersides are pale yellow to orange. During breeding season, males can have a brighter reddish color on their sides. This color change is the only easy way to tell males and females apart.
They have strong, long bodies and flat heads with small eyes. Their eyes are special, with five types of light-sensing cells. Some of these cells are very large, possibly the biggest in any animal! Their mouth is small and located underneath the head.
Lungfish can grow to be about 150 cm (5 feet) long and weigh up to 43 kg (95 pounds). On average, they are about 100 cm (3.3 feet) long and weigh 20 kg (44 pounds). Both males and females grow similarly, but females tend to get a little bigger. When taken out of the water, they are covered in slime.
The lungfish's skeleton is a mix of bone and cartilage. Their backbone is pure cartilage, and their ribs are hollow tubes filled with cartilage. Their body is covered with large, bony scales. There are ten rows of scales on each side, getting smaller on the fins. Each scale is in its own pocket and they overlap a lot. This means that important parts of their body are covered by at least four layers of scales. Two very large and thick scales cover the back of their head where the skull bone is thin.
They have strong, paddle-shaped tails that are rounded at the end. Their pectoral fins (front fins) are large, fleshy, and look like flippers. Their pelvic fins (back fins) are also fleshy and flipper-like, located far back on their body. The dorsal fin (top fin) starts in the middle of their back and connects to the tail fin and bottom fin.
The lungfish's teeth are unusual. They have two flat, slightly bent incisors in their upper jaw, which have small bumps on the back edge. After these, they have flat dental plates on both their upper and lower jaws.
Young lungfish look a bit different from adults. Their head is rounder, fins are smaller, and body is thinner. Their brain is also bigger compared to their head size when they are young. Their mouth starts at the very front but moves back as they grow. The dorsal fin on young fish usually reaches the back of their head, but it moves further back to the middle of their back as they become adults. They change slowly as they grow, and there's no sudden change like a metamorphosis (like a tadpole turning into a frog).
When they are young, lungfish have distinct mottled (spotty) patterns, with a gold or olive-brown base color. Dark spots can stay even after the mottling fades. Young lungfish can change their color quickly depending on the light, but they lose this ability as their skin gets darker.
People often think lungfish are slow and don't move much. But they can move very quickly using their strong tail if they need to escape. They are usually quiet during the day but become more active in the late afternoon and evening.
How the Australian Lungfish Breathes
A special thing about the Australian lungfish is that it has a single lung on its back. This lung helps it get extra oxygen when its gills are not enough. When the fish is very active, or during a drought, or when the water is hot (which means less oxygen in the water), the lungfish can go to the surface and breathe air into its lung. It breathes air more often when it's more active at night. This shows the lung is important for getting enough oxygen.
Unlike the lungfish from South America and Africa, the Australian species has gills on all its first four gill arches. It is also the only lungfish that only breathes air when it really needs to. This means it's a "facultative air breather." Its lung is a single long sac that runs along its body, growing out from its gut. Inside, the lung is divided into two parts that connect. These parts are further divided into spongy areas, like tiny air sacs. Tiny blood vessels run through these areas, very close to the air, allowing the fish to take in oxygen and release carbon dioxide. Lungfish breathe in air by using a special "buccal force-pump" method, similar to how amphibians breathe. When muscles in the lung walls squeeze, the fish breathes out.
The sound of a lungfish breathing out air at the surface before taking a new breath has been compared to a small bellows. Young lungfish start coming to the surface to breathe air when they are about 25 mm (1 inch) long.
Reproduction and Life Cycle
The Australian lungfish lays its eggs and lives its whole life in freshwater. Males start breeding around 17 years old, and females at about 22 years old. Males are usually mature when they are 738–790 mm (29–31 inches) long, and females at 814–854 mm (32–33.6 inches).
After a special courtship dance, the lungfish lay their eggs in pairs. They place their large, sticky eggs among water plants. They lay eggs from August to November, before the spring rains. They prefer flowing streams that are at least one meter (3.3 feet) deep.
Most eggs are laid in September and October. Scientists think that the length of the day makes them want to lay eggs. Lungfish lay eggs both during the day and at night. They are picky about where they lay their eggs. Eggs have been found on water plants rooted in gravel and sand, in slow and fast water, in shade and in full sun. But they are never found on plants covered with slimy algae, in still water, or where there is loose stuff floating on the water.
Unlike its relatives in South America and Africa, the Australian lungfish does not build a nest or guard its eggs. When they lay eggs, the pair of fish might lie on their sides or wrap around each other. They usually lay eggs one by one, sometimes in pairs, but very rarely in groups. The male lungfish fertilizes each egg as it comes out. The eggs stick to thick water plants. A freshly laid egg is half-round, delicate, and has a lot of yolk. It is covered in a sticky jelly layer. The egg itself is about 3 mm (0.12 inches) wide, but with the jelly, it's about 1 cm (0.4 inches) wide. The egg is sticky for a short time, just long enough to attach to underwater plants before silt and small water creatures cover it. If an egg falls to the bottom of the lake or river, it probably won't hatch.
A female lungfish has many eggs inside her, but in the wild, she only lays a few hundred at most during her life. In aquariums, 200 to 600 eggs have been laid at once. Lungfish don't necessarily lay eggs every year. A good egg-laying season usually happens only once every five years, no matter what the environment is like.
The eggs and young fish look a bit like frog tadpoles. But unlike frogs and other lungfish, the young Australian lungfish do not have external gills when they are very young. Inside the egg, the head and colors start to show by day 17. They hatch after three to four weeks.
The young fish grow slowly. They are about 27 mm (1 inch) long after 110 days, and about 60 mm (2.4 inches) long after 8 months. For the first week, they lie on their side, hiding in the weeds. They only move if something touches them. They will swim on their own, but often go back into their jelly covering if disturbed. Newly hatched larvae have tiny hairs on their skin and gills that create a current. This might help them breathe through their skin and gills without moving their mouth, or it might keep their skin clean from dirt and tiny creatures. Young larvae don't eat for two to three weeks while they still have yolk from the egg. Once the yolk is gone, they start to eat. Young lungfish can grow about 50 mm (2 inches) per month in good conditions.
Adult lungfish live a long time, at least 20–25 years, and many survive. An Australian lungfish named "Granddad" at the Shedd Aquarium in Chicago was the oldest living fish in any aquarium. He was already an adult when he arrived in 1933. Granddad was thought to be at least 80, and possibly over 100, when he died in 2017. Later, DNA tests showed he was about 109 years old (give or take 6 years) when he died. He was originally caught from the Burnett River in Australia. This makes the Australian lungfish the longest-living subtropical freshwater fish known to science, and one of the 12 longest-living fish species in the world.
What the Australian Lungfish Eats
The Australian lungfish mostly hunts at night. It is a carnivore, meaning it eats meat. In aquariums, they eat frogs, earthworms, pieces of meat, and fish food pellets. In the wild, they eat frogs, tadpoles, other fish, many different small water creatures, and some plants. We don't have exact numbers on what they eat, but people have seen that their diet changes as they grow. This change is linked to how their teeth develop.
Young lungfish eat from the bottom. They eat tiny crustaceans and small worms, sometimes adding stringy algae to their diet. Soft foods like worms and plants are partly crushed with a few quick bites and then swallowed. Adult lungfish strongly close their jaws to crush prey. They also use special movements of their throat bones to move food inside their mouth. The Queensland lungfish has the most basic way of doing these feeding actions.
Protecting the Australian Lungfish
The Australian lungfish is safe for now, but it is a protected species. It is against the law to catch them in the wild in Queensland. It was added to the CITES list in 1977, which controls trade in endangered animals. The lungfish is currently protected from fishing. If you want to collect them for education or research, you need a permit from the Queensland and Australian governments. It is listed as a "vulnerable" species. This means studies haven't shown it's threatened or endangered yet, but it could be in the future.
Human activities, especially building things in water, are a threat to the Australian lungfish. It is potentially at risk in its main homes, the Burnett and Mary Rivers. About 26% of these river systems are blocked by weirs and dams. These barriers stop the fish from moving freely. Also, changes in water flow below dams, used for irrigation, could harm the fish populations and cause them to lose even more genetic variety. Researcher Anne Kemp has shown how lungfish numbers have gone down in many reservoirs and rivers because dams stop new young fish from growing up.
Australian lungfish can grow very fast, but they don't start breeding until they are quite old. For a species that lives a long time and naturally has few deaths, successful egg-laying and young fish growing up don't need to happen every year. It might happen only sometimes, in cycles of medium to long periods, even in nature. These long cycles could hide the bad effects on new fish for many years. Also, many large adult fish could stay common for decades, giving no sign that the population is actually shrinking over time.
Another fish, the Mozambique mouth brooder, or tilapia, has been declared a harmful foreign species to the lungfish in Queensland.
Recent News About the Lungfish
In 2006, there were plans to build dams on both the Mary and Burnett rivers. These dams would have harmed the lungfish's home. The dams would have changed how the rivers flow, getting rid of the slow, shallow areas the fish need to lay eggs. Scientists from all over the world got involved to help save the homes of these lungfish. They said the fish were very important for understanding how animals have evolved.
As of January 2022, the world's oldest living aquarium fish is a 90-year-old lungfish named Methuselah. This lungfish is 4 feet long and weighs 40 pounds. It lives at the California Academy of Sciences' Steinhart Aquarium in San Francisco. Methuselah took over the title from Granddad. Granddad, another Australian lungfish, died at 109 years old at Chicago's Shedd Aquarium in 2017.
Lungfish and People
In a 2021 article, Karl Brandt suggested that the Australian lungfish might have been the inspiration for Gurangatch. Gurangatch is a legendary reptile-fish from the Gandangara people's stories.
See also
In Spanish: Pez pulmonado australiano para niños
