Q&A: Seadragons and climate change — IUCN Seahorse, Pipefish & Seadragon (2024)

Seadragons are iconic in their appearance, exhibiting exquisite colours, and in males brood developing embryos on the underside of their tails.

During April and May 2022, we had reports of many weedy seadragons being washed up on shorelines in the Sydney region.

As seadragon researchers for over 20 years now, we occasionally get reports from the general public of stranded seadragons, sometimes after storm activity. However, an unprecedented number of reports started arriving from beach walkers in early April 2022. I did a newspaper and a radio article to highlight this, which led to many more reports arriving.

Somewhere between 100 and 150 seadragon carcasses have been identified, probably 50 times above the normal rate of washups. We still have to sift through all the reports, many of which have images, and some of which are associated with collected carcasses. We will process each image, including checking with Seadragon Search (seadragonsearch.org) to find out about live sightings of each animal.

The seadragon strandings in 2022 are likely due to the intense storm weather in SE Australia that summer. The timing of these washups coincided with a massive set of “East Coast Low” storms (atmospheric low pressure cells increasing due to climate change) and huge rainfall; Sydney had 50% more rain in Feb – April 2022 than the whole of 2021. So, the cause of these strandings is likely a combination of freshwater influx, high sediment load, physical damage by waves and surges, and possible urban pollution and depleted food source (mysid shrimp). We are currently collecting any stranded specimens to examine for any clues on the causes of death.

Data from divers that regularly visit Sydney’s coastal reefs suggest disappearances of seadragons from most, but not all sites. We are now leading the “Sydney Seadragon Census” to work with dive clubs in estimating how many seadragons live in the seas off Sydney.

We’ve never seen anything like this scale of wash ups, even though strandings do sometimes happen during storms. Given the strong link of the East Coast Lows to human-caused climate change, we worry that such events could become more frequent and devastating in future.

Globally, reducing the use fossil fuels can help seadragon populations. Locally, it is very important to take pressure off seadragon habitats to improve their resilience to climate change. Creating and enforcing no-take marine parks is one important initiative.

A captive breeding program would be difficult and reintroduction would likely create problems for wild populations. Some public aquariums are succeeding with breeding a few seadragons, enough to support exhibits of these wondrous animals. However, releasing animals can be very risky, especially given that we have found high genetic differences among weedy seadragon populations. Releasing seadragons might introduce disease and disrupt social behaviours of the wild seadragons.

Seadragons float around shallow reefs around southern Australia or in public aquaria worldwide.

A number of children’s books and even a play have been written on weedy seadragons lately, like the one below (left). They were also featured in the writings of classic Aussie author May Gibbs in books I had as a child, written over 100 years ago (below, right).

Seadragons are an extraordinary group of fish that are related to seahorses and pipefish. They are ornately camouflaged with leaf-shaped appendages on their bodies to conceal themselves in their seaweed and seagrass habitat in Southern and Western Australia. There are three species of seadragons, the leafy seadragon, weedy seadragon and the newly discovered ruby seadragon.

Seadragons are popular in aquariums, capturing people’s curiosity because they are such an unusual fish. Because of this, they serve as excellent ambassadors for their natural environments. Aquariums around the world educate people on the amazing diversity in our oceans, with the hope that people will in turn protect and preserve our oceans.

Many public aquariums around the world have weedy seadragons on display. A few aquariums may have leafy seadragons also on display, but this is more rare due to limited availability. Check your local aquarium’s website which may inform you if they have seadragons on display.

Many aquariums acquire their seadragons from aquaculture facilities in Australia that raise seadragons that are born in human care. In recent years, a few aquariums have achieved successful breeding of weedy seadragons at their facilities, sharing them with other aquariums around the world.

Seadragons can be difficult to breed and raise in aquariums because they are very particular feeders that require a specific type of food to keep them healthy — mysid shrimp. In addition, seadragons typically require much cooler water temperatures than most other marine fishes. However, with proper nutrition and appropriate habitats, they can thrive in aquarium care.

Aquariums have learned that live mysis shrimp is the preferred food for seadragons, contributing to their overall health and increased likelihood of breeding. Deeper habitats enhance the breeding success of seadragons so exhibits with increased vertical space help facilitate their unique breeding behavior! Females will transfer their eggs to the underside of the male's tail as they engage in an elaborate courtship “dance.” The male then carries the developing embryos until they hatch.

There isn’t currently a need to release seadragons back to their natural environment. Successful rearing of seadragons in an aquarium environment establishes a sustainable population in human care, reducing the need for removing seadragons from their native waters.

Public aquariums contribute to seadragon conservation by raising awareness about these spectacular fish. Educating guests about threats to these species and how people can play a role in protecting this fragile species and their habitat is key. Aquariums can also encourage visitors to contribute financially to seadragon research and citizen science monitoring programs.