Weedy seadragon

Appearance

Adult weedy seadragons are a reddish colour, with yellow and purple markings; they have small leaf-like appendages that provide camouflage and a number of short spines for protection. Males have narrower bodies and are darker than females. Seadragons have a long dorsal fin along the back and small pectoral fins on either side of the neck, which provide balance. Weedy seadragons can reach 45 cm in length.

Naming

A more cryptic relative of the weedy seadragon is the leafy seadragon, "Phycodurus eques". In the November 2006 issue of "National Geographic" magazine, marine biologist Greg Rouse is reported as investigating the DNA variation of the two seadragon species across their ranges.

Status

It is illegal to take or export these species in most of the states within which they occur. A database of seadragon sightings, known as 'Dragon Search' has been established with support from the Marine and Coastal Community Network, Threatened Species Network and the Australian Marine Conservation Society, which encourages divers to report sightings. Monitoring of populations may provide indications of local water quality and seadragons could also become an important 'flagship' species for the often-overlooked richness of the unique flora and fauna of Australia’s south coast.

Behavior

These fish are slow-moving and rely on their camouflage as protection against predation; they drift in the water and with the leaf-like appendages resemble the swaying seaweed of their habitat. They lack a prehensile tail that enables similar species to clasp and anchor themselves.

Individuals are observed either on their own or in pairs; feeding on tiny crustaceans and other zooplankton by sucking prey into their toothless mouths. Like seahorses, seadragon males are the sex that cares for the developing eggs. Females lay around 120 eggs onto the brood patch located on the underside of the males tail. The eggs are fertilised and carried by the male for around a month before the hatchlings emerge. Seadragons, seahorses and pipefish are among the few known species where the male carries the eggs. The young are independent at birth, beginning to eat shortly after.

Mating in captivity is rare since researchers have yet to understand what biological or environmental factors trigger them to reproduce. In captivity the survival rate for weedy seadragons is about 60%.

The Aquarium of the Pacific in Long Beach, California and the Tennessee Aquarium in Chattanooga, Tennessee in the USA; and the Melbourne Aquarium in Melbourne, Australia are among the few facilities in the world to have successfully bred weedy seadragons in captivity, though others occasionally report egg laying. As of June 2008, the Georgia Aquarium in Atlanta, USA had a pregnant seadragon, which was expected to give birth in early-mid July. As of July 2012, the Monterey Bay Aquarium has also successfully bred and hatched out baby weedy seadragons on exhibit.

Habitat

The weedy seadragon inhabits coastal waters down to at least 50 m deep. It is associated with rocky reefs, seaweed beds, seagrass meadows and structures colonised by seaweed.

Predators

The weedy sea dragon is classified as Near Threatened on the IUCN Red List 2006. This species is not at present a target of the trade in Traditional Chinese Medicine, which is currently affecting seahorse numbers. However, they are likely to be threatened by the destruction of habitat that is occurring along coastal waters as a result of development and pollution.