Weedy seadragon
Leaf like fins
The weedy seadragon’s leaf-like appendages resemble the swaying kelp fronds found in their habitat. They drift gracefully around seaweed beds and seagrass meadows relying on camouflage and stealth to approach their unsuspecting prey.
Feeding on tiny crustaceans and other zooplankton, weedys suck prey into the end of their long tube-like nose. Specially developed muscles and bones allow them to generate a lot of suction.
Lacking a caudal (tail) fin, weedies must rely on their ventral (belly) and dorsal (upper) fins for swimming. Because of their limited swimming capabilities, each year a number of individuals are found washed ashore on the beaches of southern Australia.
Distinctive dragons
Despite its charismatic nature, few studies on the Great Southern Reef’s weedy seadragon have been published.
Late last year, in a first of its kind study by Klanten and colleagues it was proposed that there were four genetically distinct populations of weedy seadragons along the East coast of Australia; Central NSW, southern NSW, Victoria and Tasmania.
In the study it was noted that individuals from New South Wales were also shaped differently to those from Victoria, and occupied different habitats. Weedy seadragons from NSW and TAS are usually found between 10–20 m on rocky reefs with kelp compared to seadragons from the Mornington Peninsula (VIC), which are usually found shallower between 3–10 m depth on soft bottom with seagrass.
This new study suggests that weedy seadragons should be evaluated for the presence of a subspecies. Doing so will have considerable management and conservation implications, since Victorian seadragons are the main representatives in the global aquarium trade.
It is also noted that low levels of genetic diversity with highly restricted gene flow indicate that this endemic seadragon may lack resilience in face of future anthropogenic stressors, thus careful population assignment and management is critical.
Seasonal cycle
Weedy seadragons generally live alone except for mating time. They breed from June to January and nourish up to 250 developing eggs in a specialised area on the underside of the tail. Following a gestation period of 30-38 days, tiny free swimming seadragons and hatched. Some males having two broods per season.
In the limited research on seadragon movement, it has been reported that seadragons move within just a small area throughout the year. Results from these studies suggest resident groups of individuals with well-defined home ranges. These home ranges clearly overlapped and were similar in size for males, females and juveniles.
These resident groups may persist among years with movement out of their home ranges dictated by breeding needs like providing the young with a nursery area. Preserving the habitat of resident and nursery areas may be the key to assure the future of this protected and unique Australian fish
Fast Facts:
Species: Phyllopteryx taeniolatus
Family: Syngnathidae (Seahorses, pipefish and seadragons)
Feeding: Ambush predators
Distribution: Endemic to the GSR
Habitat: Rocky reefs and seagrass meadows, up to 50m
Size : Up to 45cm
Predators: No known predators
