Long-spined sea urchins: not trouble but in trouble

All DC islands

Since February 2022 there have been reports of Long-spined sea urchin (Diadema) die off from a number of islands in the Caribbean, including St. Eustatius, St. Maarten, Saba and Curaçao.  Marine Protected Area authorities within the Dutch Caribbean region are concerned these events could be echoing the massive die-off  of sea urchins that occurred in the 1980s which almost completely wiped out the Caribbean long-spined sea urchin populations. A new edition of the Dutch Caribbean Nature Alliance (DCNA) free digital newsletter Bionews draws attention to the current state of the die-off, what is being done to restore these populations and what you can do to help.

Importance for coral reefs

Long-spined sea urchins play a critical role in maintaining healthy coral reefs, which are essential for coastal protection and a crucial source of income for people in the Dutch Caribbean as they are a magnet for tourism. Long-spined sea urchins help sustain the delicate balance within the reef by grazing on algae, an overabundance of which can damage coral.

Caribbean-wide disease

Photo credit: Alwin Hylkema

In the mid-1980s, a disease swept through the Caribbean wiping out nearly the entire sea urchin population. In mid-February 2022, reports started emerging about new extensive die-off events in the Caribbean region. Reports from within the Dutch Caribbean first came in on March 14th from the island of St. Eustatius.  Follow on reports from the remaining Dutch leeward islands of Saba and St. Maarten soon followed.  In Curaçao, the first sightings of diseased sea urchins were reported in early June.  Two weeks later, more than 90% of the surveyed populations had disappeared.

Diadema Workshop

In April, DCNA, together with the  University of Applied Sciences Van Hall Larenstein (VHL), hosted a Diadema Restoration Workshop. This workshop gave researchers and park authority managers a comprehensive view of the overall situation of the Diadema sea urchin in the Caribbean, including the current die-off events and restoration techniques.

You can help

Citizens and tourists can also help track sea urchin health in the Caribbean by adding their observations of healthy, sick or dead urchins. These reports will help park authority managers to determine the causes and work on restoration approaches. You can report your sightings by visiting the AGRRA website (https://www.agrra.org/sea-urchin-die-off/) or contact your local Park Management Organization.

Other advice to prevent spreading the disease:

  • Wash dive gear in lots of fresh water and let sun-dry
  • Dive on uninfected sites before (known) infected sites
  • Do not step on them or (re)move them: Alive or dead

Photo source: Alwin Hylkema


Learn more

Learn more about current state, what is being done to restore these populations and what you can do to help by reading DCNA’s latest edition of its free digital newsletter Bionews available at https://dcnanature.org/news/.

DCNA’s newsletter BioNews is kindly funded by the Ministry of Agriculture, Nature and Food Quality (LNV) and DCNA’s activities by the Dutch Postcode Lottery.

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