A new report by Dragon Search SA reveals that nearly 1,700 sea dragons died during South Australia’s harmful algal bloom (HAB) from January 2025 to May 2026. The analysis, based on citizen science reports uploaded to iNaturalist, documented 1,524 dead weedy sea dragons and about 159 leafy sea dragons. Researchers are now exploring methods to increase the species’ breeding rate in hopes of a strong upcoming season.
Written by the local model on 2026-09-17,
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Story summary
A new report by Dragon Search SA, led by marine ecologist Janine Baker, reveals that nearly 1,700 sea dragons died during a harmful algal bloom (HAB) in South Australia between January 1, 2025, and May 31, 2026. The report analyzed 1,540 citizen science reports uploaded to iNaturalist by 253 people, documenting the deaths of approximately 1,524 weedy sea dragons and 159 leafy sea dragons. The HAB first appeared in South Australian waters early in 2025 and affected areas including Encounter Bay, St Vincent Gulf, Spencer Gulf, Investigator Strait, and waters off Kangaroo Island. Researchers are now exploring ways to enhance the breeding rates of these species following this significant loss.
Written for “Sea Dragon Mass Death Algal Bloom” on 2026-09-17,
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In short:
Dragon Search SA analysed 1,540 citizen science reports.
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SA → analyse → reports
It documented 1,524 dead weedy sea dragons and about 159 leafy sea dragons.
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It → document → dragons
Researchers are looking into ways to boost the species' breeding rate.
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Researchers → look → rate
Nearly 1,700 sea dragons are documented to have died during South Australia's harmful algal bloom (HAB), a new report has found, amid hopes of a strong breeding season next month.
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report → document → season
The Dragon Search SA report, led by local marine ecologist Janine Baker, analysed 1,540 reports uploaded by 253 people to citizen science platform, iNaturalist, about sea dragons, pipefish and seahorses from January 1, 2025, to May 31, 2026.
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report → lead → May
About 1,524 weedy sea dragons were recorded dead in South Australia, while 159 leafy sea dragons were also reported dead.
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dragons → record → Australia
"The weedy and the leafy in particular occur in South Australia as a world hotspot," said Dragon Search SA member Professor David Booth from the University of Technology Sydney.
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Booth → occur → Technology
"People have come from all over the world to places like Rapid Bay to see these amazing animals."
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People → come → animals
The HAB first emerged in South Australian waters in early 2025.
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HAB → emerge → 2025
Encounter Bay, St Vincent and Spencer gulfs, Investigator Strait and waters off Kangaroo Island were particularly affected by an extended outbreak that killed countless marine animals and affected human health.
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that → affect → health
Sea dragons are a part of the Syngnathidae family, which have small gill pores that can be easily clogged by microalgae, and cannot swim away rapidly from patches of water where the bloom is dense.
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bloom → have → water
Deaths caused by HAB spanned 13 species in the family, which also included pipefish and seahorses.
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which → cause → pipefish
At least 787 seagrass-dwelling brushtail pipefish mortalities were recorded, along with 574 spotted pipefish and 42 long-snout pipefish, while thousands more dead pipefish were observed in metropolitan seagrass wash-ups but not counted.
More than 160 short-head seahorse were recorded, while the south-eastern Australian big-belly seahorse washed up in small numbers.
The report found that pipefish and seahorses mainly washed up over winter and spring in 2025, but dead sea dragons continued to be observed from summer 2025 to autumn 2026.
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dragons → dwell → autumn
Boosting numbers
Professor Booth told 891 ABC Adelaide that sea dragons were entering their October breeding season in SA.
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dragons → boost → SA
He said researchers were also looking at ways to boost sea dragon numbers, including bringing pregnant males into the laboratory to hatch the eggs and rear their fry before releasing them.
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researchers → say → them
"They have a much higher survival rate that way and can boost the population,"he said.
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They → have → population,"he
"But that's only of use if we can fix the habitat.
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we → fix → habitat
There's been so much habitat destruction — huge losses of sponges, kelp, seagrasses — all those sorts of things that these animals need, and their food in little shrimps.
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animals → be → shrimps
"We really need to be working on that and we are.
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we → need → that
There's habitat restoration going on but it is a big job.
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it → be → ?
This includes shellfish reef restoration projects across multiple locations, and research to restore approximately 6,000 hectares of seagrass meadows — natural filters of microalgae — that have been lost from Adelaide's coastline since the 1950s.
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that → include → 1950s
The report stated that the HAB's impact on the full population of Syngnathidae remained unknown because there had not been an official systematic survey undertaken in the past or present.
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impact → state → past
Dragon Search SA said previous data came from divers, snorkellers, beachgoers, independent research surveys, museums, fishers and trawler bycatch, with much of it dating from the 1980s to 2000s.
"There is no doubt that leafy sea dragon numbers are lower than pre-bloom in those inshore habitats, but offshore numbers away from dived locations remain undocumented," Janine Baker said.
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Baker → say → locations
Since spring 2025, citizen science divers in seven areas of SA had been documenting live sea dragon records in near-shore areas monitored by Dragon Search SA.
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divers → document → SA
This included small aggregations of juvenile weedy sea dragons.
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This → include → dragons
Professor Booth said there had been reports of sea dragons in Second Valley but at Rapid Bay, one of the state's renowned dive sites, the ongoing closure of the old jetty and its 20-metre exclusion zone for diving was hindering any surveying of the species.
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closure → say → species
He is a sea dragon specialist on the International Union for Conservation of Nature, which lists weedy sea dragons as "vulnerable" on its red list for species at a higher risk of extinction.
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which → list → extinction
It also includes the leafy sea dragon, currently listed in the "least concern" category.
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It → include → category
"Globally, people are concerned,"Professor Booth said.
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Booth → say → ?
"Locally, of course, your wonderful citizens, scientists and government people are very, very worried about your state [marine] emblem the leafy, and the weedy as well, which we have in our lab in boxes and boxes of carcasses.
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we → have → carcasses
The Aporia