That’s Mr. Slate Pencil to you. Meet a resident of Blazer Reef, the slate pencil sea urchin Eucidaris tribuloides.
During a routine afternoon feeding in the tank last Friday (Oct 24), Mr. Slate was observed releasing his gametes into the water column. From this observation, we learned two things… one – our urchin is a male, as he is seen releasing sperm into the water column. And two – he seems to be healthy and happy as he is spending energy on gamete production.
Previous work suggests that spawning in sea urchins is associated with the lunar cycle. This observation was one day following the new moon. Blazer Reef stays a warm 77.5o F and salinity ranges from 33-34 ppt.
You can explore the anatomy of a sea urchin here: http://web.stanford.edu/~seastar/VirtualUrchin/urchinanatomy.swf