Bald sea urchin disease

Bald sea urchin disease is a bacterial disease known to affect several species of sea urchins on Mediterranean Sea, North Atlantic and California coastlines. Research suggests two pathogens are responsible for the disease, Listonella anguillarum and Aeromonas salmonicida.

Infection generally occurs at the site of an existing physical injury. The affected area turns green and spines and other appendages are lost. If the lesion remains shallow and covers less than 30% of the animal's surface area, the animal tends to survive and eventually regenerates any lost tissue. However if the damage is more extensive or so deep that the hard inner test is perforated, the disease is fatal.