[Coral-List] Concerns for Diadema – your help is needed

Judith Lang jlang at riposi.net
Wed Mar 30 16:24:50 UTC 2022

Concerns for Diadema – your help is needed

Submitted by AGRRA (Atlantic & Gulf Rapid Reef Assessment Program) in collaboration with the Diadema Response Network

The Caribbean may be facing another widespread die-off of sea urchins. Diadema antillarum, also known as the long-spined sea urchin, is one of the most important herbivores on Caribbean coral reefs, removing algae and maintaining open space for coral growth.

In mid-February 2022, we first learned of extensive Diadema die-offs close to Charlotte Amalie Harbor in St. Thomas, U.S. Virgin Islands (USVI). Within a month, additional mortality events had been independently observed elsewhere in St. Thomas plus nearby St. John, as well as Saba, St. Eustatius, Dominica, Jamaica, St. Vincent, and perhaps other islands. See Diadema Map at https://www.agrra.org/sea-urchin-die-off/ <https://www.agrra.org/sea-urchin-die-off/>.

Diadema previously experienced a massive die-off throughout the Caribbean in the early 1980s. Sampling at the time was inadequate to determine the cause of their demise. Few Diadema populations have since fully recovered, resulting in algal-dominated states on many of the region’s reefs.

While we do not know what is causing these dispersed die-offs, the speed at which large numbers of sick urchins are now dying on affected reefs resembles the mass mortality event of four decades ago. We worry that a real crisis is developing in the Caribbean, where stony coral tissue loss disease (SCTLD) has already caused widespread coral losses affecting about 34 coral species in 20 countries/territories.

Signs of sick and dying urchins include detaching from substrate through loss of control of their tube feet, followed by loss of spines, tissue loss and rapid death. See website for photos/videos: https://www.agrra.org/sea-urchin-die-off/ <https://www.agrra.org/sea-urchin-die-off/>
Diadema Response Network

A region-wide collaboration–the Diadema Response Network–has quickly formed to track and try to understand the cause of this recent die-off of Diadema (and possibly other sea urchins). We need your help in reporting healthy, sick or dead urchins and in collecting samples to search for the causation of the die-off.

Report sightings of healthy, sick, or dead urchins

Help us track sea urchin health in the Caribbean by adding your observations of healthy, sick, or dead urchins. This survey will allow us to determine the spatial extent of the die-offs and broadcast their chronology in real time. It is as important to report healthy populations of Diadema as ones that are rapidly dying. 

Submit report here: https://survey123.arcgis.com/share/7879b018f20f4602ad82c24c4e0d1e98 <https://survey123.arcgis.com/share/7879b018f20f4602ad82c24c4e0d1e98>
Help us collect Diadema tissue samples

Help us try to understand why Diadema are now dying.
In areas where Diadema are dying, collect healthy looking and sick urchins - see collection guidelines at https://www.agrra.org/sea-urchin-die-off/ <https://www.agrra.org/sea-urchin-die-off/>.
In areas where the die-off has not been reported, collect healthy urchins (not more than 3 per site). Tissue samples will be used for histopathological and microbiological or molecular analyses.
Contact us at Diadema at agrra.org <mailto:Diadema at agrra.org> prior to collection to coordinate sampling efforts.
Help stop the potential spread

The causative agent of the urchin deaths is not known but may it be waterborne. Pathogens can survive on snorkel/dive gear and may spread through contact. To potentially help reduce the spread of  pathogens, snorkelers and divers can:
Have good buoyancy and don’t touch urchins or other reef life.
 Rent gear locally.
 Decontaminate dive gear after each dive.
Guidelines to decontaminate dive gear and prevent spread were developed through collective efforts for responding to the stony coral tissue loss disease outbreak. For more information see NOAA’s website (https://floridakeys.noaa.gov/coral-disease/citizen-participation.html <https://floridakeys.noaa.gov/coral-disease/citizen-participation.html> and MPAConnect info-posters (www.agrra.org/coral-disease-resources/ <http://www.agrra.org/coral-disease-resources/>).

FOR MORE INFORMATION, visit the Diadema website https://www.agrra.org/sea-urchin-die-off/ <https://www.agrra.org/sea-urchin-die-off/>
Additional strategies for sampling seawater and sediment and an evaluation of the potential for Diadema rescue are being explored. For further information, contact us at Diadema at agrra.org <mailto:Diadema at agrra.org>
The Diadema Response Network is a collaboration of numerous partners of which the initial planning group includes:

    Judith Lang, Atlantic & Gulf Rapid Reef Assessment Program (AGRRA), jlang at riposi.net <mailto:jlang at riposi.net>
    Patricia Richards Kramer, AGRRA, perigeeenv at gmail.com <mailto:perigeeenv at gmail.com>
    Kimani Kitson-Walters, Caribbean Netherlands Science Institute, St. Eustatius, Kimani.kitson-walters at nioz.nl <mailto:Kimani.kitson-walters at nioz.nl>
    Alwin Hylkema, University of Applied Sciences Van Hall Larenstein, Saba, alwin.hylkema at hvhl.nl <mailto:alwin.hylkema at hvhl.nl>
    Matthew Warham, Department of Planning and Natural Resources, USVI, Matthew.warham at dpnr.vi.gov <mailto:Matthew.warham at dpnr.vi.gov>
    Stacey Williams, The Institute for Socio-Ecological Research, Puerto Rico, Stcmwilliams at gmail.com <mailto:Stcmwilliams at gmail.com>
    Joshua Patterson, University of Florida, Florida, joshpatterson at ufl.edu <mailto:joshpatterson at ufl.edu>
    María Vega Rodríguez, Puerto Rico Department of Natural and Environmental Resources, Puerto Rico, maria.vega at drna.pr.gov <mailto:maria.vega at drna.pr.gov>
Guidelines for collecting urchin samples for histopathology were compiled by Judith C. Lang, Yasunari Kiryu (Yasunari.Kiryu at myfwc.com <mailto:Yasunari.Kiryu at myfwc.com>), Thierry M. Work (thierry_work at usgs.gov <mailto:thierry_work at usgs.gov>), Ruth Francis-Floyd (rffloyd at ufl.edu <mailto:rffloyd at ufl.edu>), Michelle M. Dennis (mdenni12 at utk.edu <mailto:mdenni12 at utk.edu>) and Esther C. Peters (epeters2 at gmu.edu <mailto:epeters2 at gmu.edu>), with additional input by Marilyn Brandt (mbrandt at uvi.edu <mailto:mbrandt at uvi.edu>), Alwin Hylkema, Joshua Patterson, Kimani Kitson-Walters, Matthew Warham, Stacey Williams and Patricia Richards Kramer.

Visit AGRRA's Diadema Response Network page for more information and resources. https://www.agrra.org/sea-urchin-die-off/ <https://www.agrra.org/sea-urchin-die-off/>

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