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Leafy SeadragonLeafy Seadragon

Phycodurus eques

Description

Belonging to the same family as seahorses and pipefishes, the leafy seadragon shares the hard, bony plates instead of scales and the long, thin, pipe-like snout with its cousins, but differs dramatically from them by having leaf-like appendages all over its body. It also differs by having small, transparent dorsal and pectoral fins, and by lacking caudal or pelvic fins. Lastly, the leafy seadragon's tail cannot be coiled like that of seahorses.

The maximum length of a leafy seadragon is about 14 inches, with the tail being about half of the total length. General body color is brown to yellow, with olive-tinted appendages, but coloration varies slightly depending on the vegetation amongst which it lives.

The leafy appendages, combined with an ability to change color when needed, allows the leafy seadragon to blend into its environment, an effect that is compeleted by its habit of swaying in the water like the plants it hides among.

Distribution and Habitat

Leafy seadragons live in the temperate waters (55-67 F) off western and southern Australia, among rocky reefs, sand patches close to the reefs, seaweed beds, and seagrass meadows. They are found from the surface down to a depth of about 80 feet.

Diet

Because it does not have a stomach, the leafy seadragon must eat almost constantly, and may cover a wide area in search of prey. Its favorite food is mysid shrimp (aka sea lice), but it will also take other small crustaceans, plankton, and larval fishes. It has no teeth, so prey is swallowed whole after being sucked into the mouth.

Reproduction

Breeding season runs from August through March.

As is the case with the seahorses, it is the male leafy seadragon that broods the eggs. They differ, however, in that the male seahorse breeds his eggs in a special pouch while the male leafy seadragon broods his on a "brood patch" under his tail. The female leafy seadragon pushes 100-250 tiny, pinkish eggs onto that patch, where they are fertilized by the male. The skin of the brood patch then hardens into a tiny cup around each individual egg, and the entire brood is carried by the male for 6-8 weeks. Unlike seahorses, which usually release the entire brood at one time upon hatching, the leafy seadragon only releases a few fry at a time, aking from a few hours to several days to let go of the entire brood.

Newly hatched fry look like tiny versions of adults except for being silver and black in color and lacking the leafy appendages. Very vulnerable to predation, they mature fairly rapidly and can begin hunting at about two days and reach full size by their second year. Maximum lifespan of leafy seadragons in the wild is unknown, but it is believed the average lifespan is 7-10 years.

Other Behavior

Leafy seadragons are solitary except during the breeding season, when they congregate in selected shallow bays to pair off and mate.

Slow swimmers with fragile bodies, leafy seadragons tend to prefer drifting with the current to swimming. If you are able to watch a leafy seadragon long enough, however, you may be able to see it moving its fins just enough to keep it within the plant mass concealing it.

Conservation Status

Leafy seadragons are listed as near threatened due to habitat destruction, pollution, and poaching, and are fully protected by Australian law.

Scientific Classification

phylum Chordata
subphylum Vertebrata
superclass Osteichthyes
class Actinopterygii
order Syngnathiformes
family Syngnathidae
genus & species Phycodurus eques

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The Robinson Library >> Science >> Zoology >> Fishes >> Class Actinopterygii

This page was last updated on March 24, 2017.