Fascinating fauna: Leafy sea dragon, the rare fish that looks like a floating seaweed
In the rocky reefs of the waters of southern and western Australian coasts, there lives a rare fish with leaf-shaped fins. It is known as leafy sea dragon or Glauert’s sea dragon. This charismatic species resemblance floating seaweed. Leafy sea dragons blend with the algae on stony reefs, where they survive, owing to their leaf-shaped fins. These 1-foot-long (30 cm) creatures consume tiny plankton crustaceans and have good vision to identify and attack their prey. And this is not it. There are many more facets to these organisms. Let’s read to know them!
Sea dragons are closely related to seahorses
Leafy sea dragons are relatives of seahorses and pipefish. Because of the vivid yellows, purples, blues and reds on their bodies and appendages, leafy sea dragons are frequently more colourful than seahorses. Both seahorses and sea dragons have long, tube-like snouts and equine-like heads and necks. Unlike seahorses, sea dragons are only found in Australia, lack internal embryo development and have leaf-like structures all over their body. The use of their tails is one of the main distinctions between the two. Although leafy sea dragons have tails, they rarely use them. On the other hand, seahorses commonly use their tails for wrapping around something while drifting in the water. However, both species can’t swim well.
Male leafy sea dragons are the child bearers!
Like their close cousin seahorse, a male leafy sea dragons carry their mate’s eggs until they hatch. Although they do not have pouches as seahorses do, the sea dragons develop a brood patch when the mating season approaches. These patches have a spongy texture and are located on the underside of the sea dragon’s tail where it carries the eggs. The female lays one egg in each of these tiny cup-shaped indentations. Fertilisation occurs when the eggs are transferred from the female to the male. The brood patches can accommodate about 250–300 eggs in one go, which hatch after 4 to 6 weeks.
The leaf-like fins serve different purposes
Leafy sea dragons have unique, leaf-like fins to perfectly resemble seaweed. However, not all these fins are meant for swimming. Only two, nearly transparent, thin fins are used for wading through the water. A leafy sea dragon uses one pectoral and one dorsal fin to propel itself through the water. It uses the tail as a rudder (for controlling the movement) and swiftly oscillates its two tiny fins to move through the water.
They are considered near threatened
In 2006, leafy sea dragons were classified as Near Threatened on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. This was mainly because of preying and using them as pets. Yes, because of their unique appearance, people started hunting them and keeping them as pets. In addition, habitat loss owing to human activity, pollution, excessive fertiliser runoff and fishing have gravely jeopardised this species. Scientists believe that this species is at risk of extinction. Therefore, it is essential to reduce human activities to protect this species. In line with this, governments have strictly controlled the leafy sea dragon trade.
The plant like appearance makes for a perfect camouflage
Leafy sea dragons live on tiny crustaceans such as sea lice or mysids and they are easily preyed upon by their sea predators. To avoid this, they have evolved into their plant-resembling forms. They blend well in with the algae on the stony reefs and seagrass beds where they thrive. These creatures move slowly and guess the topmost speed they can travel at: 490 feet per hour. Slow for the sea world of course! That is why they rely on their camouflage to escape predators.