Predators, parasites, and diseases Mass mortality of sea urchins was first reported in the 1970s, but diseases in sea urchins had been little studied before the advent of aquaculture. In 1981, bacterial "spotting disease" caused almost complete mortality in juvenile Pseudocentrotus depressus and Hemicentrotus pulcherrimus, both cultivated in Japan; the disease recurred in succeeding years. It was divided into a cool-water "spring" disease and a hot-water "summer" form. Another condition, bald sea urchin disease, causes loss of spines and skin lesions and is believed to be bacterial in origin.
Predators, parasites, and diseases Mass mortality of sea urchins was first reported in the 1970s, but diseases in sea urchins had be?en little studied before the advent of aquaculture. In 1981, bacterial "spotting disease" caused almost complete mortality in juvenile Pseudoce?ntrotus ?depressus and Hemicentrotus pulcherrimus, both cultivated in Japan; the disease recurred in succeeding years. It was divided into a cool-water "spring" disease and a hot-water "summer" form. Another con?dition, bald sea: urchin disease, causes loss of spines and skin lesions and is believed to be bacterial in origin.