Zoology A Closer Look: Phycodurus eques (Leafy Seadragon)

Discussion in 'Zoology' started by mscbkc070904, Feb 18, 2005.

  1. mscbkc070904

    mscbkc070904 Premium Member

    Common Name: Leafy Seadragon
    Scientific Name: Phycodurus eques
    Family: Syngnathidae

    Introduction: Sea Dragons are arguably the most spectacular and mysterious of all ocean fish. Though close relatives of sea horses, sea dragons have larger bodies and leaf-like appendages which enable them to hide among floating seaweed or kelp beds. Sea dragons feed on larval fishes and amphipods, such as and small shrimp-like crustaceans called mysids ("sea lice"), sucking up their prey in their small mouths. Many of these amphipods feed on the red algae that thrives in the shade of the kelp forests where the sea dragons live.

    As with their smaller common seahorse (and pipefish) cousins, the male sea dragon carries and incubates the eggs until they hatch. During mating the female deposits up to 250 eggs onto the "brood patch" on the underside of the male's tail. After about eight weeks, the brood hatches, but in nature only about 5 per cent of sea dragons survive to maturity (two years). A fully grown Leafy Sea Dragon grows to about 18 inches (45 cm).

    Leafy Sea Dragons are very interesting to watch-- the leafy appendages are not used for movement. The body of a sea dragon scarcely appears to move at all. Steering and turning is through movement of tiny, translucent fins along the sides of the head (pectoral fins, visible above) and propulsion derives from the dorsal fins (along the spine). Their movement is as though an invisible hand were helping, causing them to glide and tumble in peculiar but graceful patterns in slow-motion. This movement appears to mimic the swaying movements of the seaweed and kelp. Only close observation reveals movement of an eye or tiny fins.

    Most sources of information about sea dragons say they are found in the ocean waters of southern Western Australia, South Australia and further east along the coastline of Victoria province, Australia. Sea dragons are protected under Australian law, and their export is strictly regulated. A 1996 assessment by the Australian government's Department of Environmental Heritage indicates "It [the Leafy Sea Dragon] is now completely protected in South Australia because demand for aquarium specimens threatened the species with extinction." Currently the specific law which protects them is called the Environment Protection and Biodiversity Conservation Act 1999. For a February 2002 updated overview of the leafy sea dragon, see this page from the Department of Environmental Heritage site.


    Distribution in Australia: Lancelin WA to Wilsons Promontory, Vic. Commonly found in SA, where it is a protected species.

    Habitat: Shallow protected reefs, seaweed beds, seagrass meadows and around any structures colonised by seaweed. Although found in depths of up to 50 m, they are more often seen in shallow coastal waters between 4 - 30 m depth. Juveniles occupy shallow water while adults prefer depths below 10 m.

    Size/Age: Leafy seadragons grow to about 430 mm.


    Adaptations:

    Camouflage: The leafy seadragon exhibits one of the ocean’s best examples of camouflage. It is characterised by the leaf-like appendages that are part of its body.


    Mimicry: By employing a rhythmic, rocking motion, seadragons can imitate the surrounding seaweed. Their forward and backward movements are similar to the way kelp moves when being swept by an ocean surge.


    Skeleton: The body lacks scales but are instead protected by bony plates


    Summary:

    Body: Adult leafy seadragons are green to yellow-brown in colour with thin, dark edged pale bands. Colour may vary according to individuals and depth. Leafy seadragons have several long sharp spines along the sides of the body and, unlike weedy seadragons, the eyes are located slightly above the snout.


    Locomotion: As well as looking like seaweed, seadragons move in a similar swaying motion as seaweed would in the water current. They are not strong swimmers, having tiny fins on either side of their head and a long shimmering dorsal fin along their back, which propels their body through the water.


    Reproduction: As in seahorses, seadragons reverse roles when rearing young. The female lays her eggs under the male’s tail. He has the responsibility of looking after the eggs. Eggs remain under the adult male’s tail for about two months, then hatch. The juveniles grow rapidly, attaining a size of about 70 mm after just three weeks. While they have been found in depths of up to 50 m, they are more often seen in shallow coastal waters.


    Feeding: Long snouts end in tiny toothless mouths adapted for sucking up prey such as mysid shrimp. The family name, Syngnathidae, is Latin and refers to the jaws of these fish that have evolved into a tube-snouted mouth.


    Further Information:

    Family: Seadragons belong to the Family Syngnathidae, which includes seahorses and pipefish. Although seadragons resemble seahorses in appearance, they are more closely related to pipefish. Seadragons were named after the dragons of Chinese legends.


    Very special Australians: Leafy seadragons are endemic to the southern coast of Australia, ie. they are only found in this part of the world.

    Images:
    Leafy Sea Dragon #8, Phycodurus eques
    Leafy Sea Dragon #5, Phycodurus eques
    Leafy Sea Dragon #2, Phycodurus eques
    Leafy Sea Dragon profile view, Phycodurus eques

    IMO these guys are absolutely gorgeous sea creatures, its amazing the colors they portray and the elegance when they move.
     
  2. bodebliss

    bodebliss The Zoc-La of Kromm-B Premium Member

    This is a great article about a creature I didn't even know existed, but after viewing the pictures I'm wondering how they taste fried in butter and wine sauce. Are they edible?
     
  3. mscbkc070904

    mscbkc070904 Premium Member

    No they are not edible at all, in fact they are very small, avg size 44mm...not very big and mainly cartliage as well as they are highly endangered species too.