Mass mortality of collector urchins Tripneustes gratilla in Hawai`i

Diseases of Aquatic Organisms
By: , and 



As grazers, sea urchins are keystone species in tropical marine ecosystems, and their loss can have important ecological ramifications. Die-offs of urchins are frequently described, but their causes are often unclear, in part because systematic examinations of animal tissues at gross and microscopic level are not done. In some areas, urchins are being employed to control invasive marine algae. Here, we describe the pathology of a mortality event in Tripneustes gratilla in Hawai`i where urchins were translocated to control invasive algae. Although we did not determine the cause of the mortality event, our investigation indicates that animals died from inflammation of the test and epidermal ulceration, followed by inability to maintain coelomic fluid volume, colonization of coelomic fluid by opportunists (diatom, algae), and inappetence. Parasites, bacteria, fungi, and viruses were not evident as a primary cause of death. Pathology was suggestive of a toxin or other environmental cause such as lack of food, possibilities that could be pursued in future investigations. These findings highlight the need for caution and additional tools to better assess health when translocating marine invertebrates to ensure maximal biosecurity.

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Publication type Article
Publication Subtype Journal Article
Title Mass mortality of collector urchins Tripneustes gratilla in Hawai`i
Series title Diseases of Aquatic Organisms
DOI 10.3354/dao03716
Volume 153
Year Published 2023
Language English
Publisher Inter-Research Science Publisher
Contributing office(s) National Wildlife Health Center
Description 12 p.
First page 17
Last page 29
Country United States
State Hawaii
Other Geospatial Kanehoe Bay
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