Image of status for Urchins, showing Very Poor result, Declining trend and low data confidence.

The status of sea urchins (Heliocidaris species) in Port Phillip Bay in 2022-2023 was Very Poor and the trend is Declining. The 2022-2023 status of the over abundant endemic species Heliocidaris erythrogramma in Port Phillip Bay is Very Good and the trend is improving. This status is informed by the latest available time-series data from Reef Life Survey. For the over abundant Heliocidaris erythrogramma a threshold of 8 urchins per square metre was used and fluctuations above this scored a poorer status. The confidence score for this data is Low.

Urchins play a unique role in being both beneficial and harmful to reefs depending on their abundance. Over the last 20 years Port Phillip Bay

Image of a sea urchin amongst some rocks
Photo credit: Heliocidaris erythrogramma Julian Finn / Museum Victoria

has seen an increase in reef areas becoming sea urchin barrens, where ecosystem function and species diversity is reduced due to grazing pressure from sea urchins. The status was calculated using a Biological Quality Ratio from data provided by Reef Life Survey and the Victorian Subtidal Reef Monitoring Program. For more detail on how this status was calculated view the methodology section.

Data Source: Reef Life Survey
Map Data Source: Reef Life Survey
Data contributors and acknowledgements:

Parks Victoria logo Reef Life Survey logo

Page last updated: 17/04/24