Standard Talk (15 mins) Australian Society for Fish Biology Conference 2022

Weedy (common) sea dragon strandings in Sydney in April 2022: causes and population impacts (#145)

David J Booth 1 , Giglia A Beretta 1 , O. Selma Klanten 1 , Andrew Trevor-Jones 1
  1. University of Technology, Sydney, Broadway, NSW, Australia

Weedy seadragons (Phyllopteryx taeniolatus) are iconic inhabitants of Australia’s Great Southern reef.  Our long-term monitoring and sampling research (since 2001) has indicated population fluctuations and some declines in SE Australia over the last two decades, and that there is high spatial genetic and morphological structuring.  Climate-change impacts are expected, particularly at northern range limits, via loss of kelp habitat and also mysid shrimp depletion.


In February-April 2022, a series of severe climate-related East Coast Lows battered SE Australia, and in April local beach walking citizens reported patchy strandings of over 150 weedy seadragons on shorelines from Gosford to Wollongong.  Images of the stranded dragons were used to check on previous live sightings, and carcasses were examined to check sex and body size.   Long term monitoring by researchers and citizen-scientism suggest densities of weedys at some reef sites may have declined as a result, indicating this acute impact of climate change is of concern for this species.  Also, beachcomber observations can be a useful monitoring tool for impacts on coastal marine species.