Posted by: ktzefr | May 29, 2012

St. John in June: Urchins

“…in between the waves…the sea runs off and edges back.”  ~ Javier Heraud (Peru)

Sea Urchins, Hawksnest Beach, St. John, USVI; Photo:KFawcett

Yes, the water IS this clear at Hawksnest Bay on the island of St. John in the US Virgins.  Sea urchins find many hiding spots in the shallow water close to shore.  Years ago I knew two things about sea urchins — they were abundant in the Caribbean and I should keep my distance because they could sting.  I still keep my distance when I’m wading or swimming near the reef, but it’s good to see them amongst the rocks and coral.  It’s amazing how the lives of thousands of people can be affected by the presence or absence of a little critter that can fit in your palm. 

In the early 1980s a plague destroyed most of the urchins (Diadema antillarum, Long-spined black sea urchin) in the Caribbean, causing a chain reaction of events.  These urchins are the chief grazers of algae on the coral reefs.   When they are diminished in number algae overgrowth stunts and even reverses the development of the coral.  Without the coral for food and shelter a number of dependent fish species also die.  The sea urchins’ demise in the 1980s eventually hurt the economies of a number of small Caribbean island nations that depended on the health and beauty of their coral reefs to draw divers, snorkelers, and other tourists. 

Today, artificial reefs are being built and research is being done to repopulate and relocate urchins to the coral reefs.  It’s not an easy task, however, since much of the algae overgrowth has to be removed before reintroducing the urchins.  Mature algae has toxins that can kill them. 

Support World Oceans Day — celebrated around the world every June 8. 

For more info about sea urchins…

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