[en] Several measurements can be employed to quantify the body size of echinoids. We evaluate here the accuracy of three measurements on the sea urchin Paracentrotus lividus (test diameter, fresh body weight and immersed weight - the weight of the sea urchin when immersed in seawater -) and discuss their respective potentials. The immersed weight appears to be by far the most accurate, providing it is standard- ized, but also the most time-costly measurement. Allometric relationships and formula for calculating a stan- dard immersed weight for P. lividus are also provided.
