Stress can be either chronic or acute.
Mortalities can occur as a result of a prolonged or short acute stress such as desiccation, thermal shock. To establish levels of spat quality. To use the laboratory techniques in a case study where three different densities of scallops were placed in trays in the sea and compared to each other and to the reference qualities. After reliable spat qualities had been determined various laboratory techniques were compared as possible methods for quality assessment. These are shown in the following table.