Dataset: Sea urchin (Eucidaris) quadrat counts at twelve sites in the Galápagos Islands in 2016-2017

Quadrat survey techniques were used at twelve sites in the Galápagos Islands in 2016-2017 to determine counts and species density of Eucidaris sea urchins.  Quadrats were 0.25 square meter areas randomly established following the methods of Witman and Smith (2003).  A ‘quadrapod’ camera framer holding an underwater camera was used to capture digital photo quadrat images (42 megapixel resolution) which were subsequently viewed on a computer. This was the same field sampling method described in Witman and Smith (2003) except this study used a Sony AR digital camera in a Nauticam underwater housing. The sampling was achieved by a diver swimming along the transect tape and taking photo quadrats at the random marks on the tape.  The large thick spines of the Eucidaris galapagensis enable the sea urchins to be readily recognized and counted. Sea urchins were manually counted from digital images of the quadrats (photo quadrats) displayed on a computer screen. The counts were then entered by quadrat and site into an Excel spreadsheet.