Leafy Sea Dragon

The leafy sea dragon is part of the family syngnathidae, which includes other species such as the pipefish and seahorses. Its scientific name is Phycodurus eques. The Latin words phyko, which means seaweed, and oura, which means tail, are the origin of the name phycodurus. Eques is derived from the Latin word “equus,” which means horse. One of the more interesting creatures in the ocean, the leafy sea dragon is endemic to the seas off Tasmania, South and East Australia. Alongside its dragon-like appearance, their body resembles the many leaves on the coral reefs and sea floor. The leafy sea dragon has been known to live in the wild for up to nine years.

Featured image credit: James Rosindell (CC BY 4.0)

Appearance

The leafy sea dragon has developed an impressive camouflage strategy, resembling seaweed to escape predators’ attention. At about 20–24 cm (8–9.5 in) in length, it is larger than its relative, the Seahorse. Its olive-colored patches and yellow-to-brown pigmentation help it blend in with the aquatic vegetation where it lives. The way its skin grows creates an effect that is similar to a leaf floating through the water. The sea dragon also has the ability to change its color, helping it adapt to its surroundings and protecting it from predators. The sea dragon utilizes a system of fins along the side of its head to help with direction. However, its rigid outer skin limits its mobility.

Two other varieties of Sea dragons exist. The weedy sea dragon only has a few appendages, but they are sufficient to assist in its environment-blending. Alternatively, the deep red ruby Sea dragon only has a few stumpy, extremely short limbs. Due to their weak swimming abilities, all three of these animal species tend to drift with the currents.

Diet

The leafy sea dragon feeds mainly on plankton and small crustaceans, zooplankton, worms, small fish, mysids, and fish larvae. Since they lack teeth, they use their long noses to hunt for these small prey. Other species they eat include larval fish and amphipods.

To catch thier prey, the sea dragon will hide out and ambush their victim. Despite their small mouths, they suck their prey in with a strong jaw suction to grab it and devour their prey entirely once it is in their mouths. 

Credit: James Rosindell (CC BY 2.0)

Habitat

The leafy sea dragon mostly inhabits the regions of South Australia and Western Australia. They live in the coastal waters of Australia and are sometimes seen in Tasmania. Rocky reefs tend to be their most optimal habitat, but they can also be spotted close to seaweed beds, mangrove forests, and seagrass beds.

They are often found in shallow coastal areas but may sometimes be found up to 150 ft below the sea. The fact that ruby sea dragons have been found dwelling in considerably greater depths than the other species could be the reason why they were just recently identified. 

Credit: John Turnbull

Scientists used to believe that sea dragons remained in a very limited habitat area. However, it has since become known that they have the ability to explore other sections of habitat up to several hundred meters away.

Reproduction

Male leafy sea dragons bear the young, just like sea horses do. But unlike sea horses, which have a pouch, the male sea dragon has a spongy brood patch on the underside of its tail, which is where females lay their bright-pink eggs during mating.

Sea dragon females can produce as many as 300 bright-pink eggs at a time. In the process of moving from the female to the male, the eggs are fertilized. The eggs are incubated and carried to term by the males, then release the baby sea dragons into the water after around 4 to 6 weeks. The offspring are known as fry hatch, and they resemble miniature versions of their parents but without any of the adult’s camouflaging leafy appendages. Soon after hatching, thier offspring becomes independent.

As mostly solitary creatures, the male sea dragons court the female sea dragons and pair up with them purely to breed. For the rest of their lives, they live alone. From the ages of two years and onwards, they reach sexual maturity.

Threats

The conservation status of the leafy sea dragon is endangered due to many threats to its existence. One of the greatest man-made threats is the roaring collector industry. Although their exploitation is illegal, many leafy sea dragons are used for alternative medicine purposes. Additionally, people take these species and keep them as aquarium pets, thus reducing their numbers. Fishing nets do occasionally entangle sea dragons, and when this happens, they often perish.

They are also prone to predation at an early age due to their inability to swim quickly and cover distances. This vulnerability also leads to many sea dragons being washed up onto shorelines from deeper water during storms and extreme weather.

Other artificial threats include pollution, sea plastic, and industrial run-off from coastal human activities. The loss of habitat, particularly seaweed and seagrass beds, is a major danger to the survival of these creatures.  This all contributes toward a more difficult habitat for sea dragons.

Credit: lecates (CC BY 2.0)

Threats to Humans

As a mostly prey animal that feeds on smaller ocean animals, the leafy sea dragon does not pose any real threat to humans. As a slow-moving animal, sometimes being seen to remain in the same position for up to 68 hours, even if they were a threat to humans, they would be fairly easy to avoid.

Facts about the Leafy Sea Dragon

• Sea dragons disguise themselves as seaweed, or leaves, to avoid predation.
• The males take responsibility for caring for the fertilized eggs.
• The sea dragon has fins along the side of its head which allow it to direct itself.
• It has been known for sea dragons to move up to 150 m in one hour.
• Sea dragons don’t have a direct predator.
• They are recognized as a Totally Protected Species in South Australia.
• Since they are shy creatures, so when encountering a human, they drift away.
• Sea dragons are completely harmless to humans.
• Just like scuba equipment, sea dragons use swim bladders to maintain buoyancy.

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