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Tripneustes gratilla (Linnaeus 1758)

Collector Urchin

Stephanie Lyon (2014)



Fact Sheet



Physical Description


Life History & Behaviour

Anatomy & Physiology

Evolution & Systematics

Biogeographic Distribution

Conservation & Threats

References & Links


Tripneustes gratilla (T. gratilla) are a species of sea urchin that is primarily found on the coastal areas of the west indo-pacific region. Being marine benthic organisms they are found at depths between 2-30m. Perhaps one of the most beautiful urchins they come in a range of colors with orange being the primary color. T. gratilla are found in a range of habitats such as seagrass and algal beds, coral reefs, sandy substrate and rocky shorelines, with the habitats varying depending on the biogeographic location.  Locomotion is enabled through the use of tube feet which also aid in respiration as well as 5 pairs of external gills on the test.  The water vascular system aids in the movement of these feet by hydraulic pressure produced via the water vascular system. T. gratilla reproduce sexually via spawning which require certain oceanic conditions in order to trigger spawning and ensure the survival of the larvae.  A short experiment was conducted on the fertilization rates of T. gratilla with altering pH levels of the water using a generic garden fertilizer, the results of which being significant. These urchins are one of few edible species which is grown in aquaculture ponds for the purpose mass production. 

Figure 1: ​T. gratilla grouping together in the laboratory showing variation and the phenotypes. Photo: Stephanie Lyon