# Table 4. Descriptions and definitions of the cost categories used to define the total costs of a mussel farm establishment.

 Cost category Formulation relationship Farm establishment depreciation (ropes, nets, etc.) Based on the initial investment cost (per cultivation line) and on the assumption of a common life span for all assets. =[cost of fixed asset (initial investment)] / [life span (years)] Automation equipment (water vessel) depreciation Estimated using the activity level (average hours that the vessel is being used per day) and the total lifetime hours of the vessel. = [automation investment*hours used per day] / [total lifetime hours] Standard operational costs Calculated per cultivation line, based on the annual amount of money spent for basic consumable materials. =[average operational costs per line] * [number of lines in each farm] Standard labor costs Calculated from the average man-days required per cultivation line for optimum productivity. The man-days required per line are negatively connected to the total investment on automation equipment, as a bigger vessel is contributing to labor attenuation. =[optimum man-days per line] * [average wage in the area] Extra labor costs Determined from the average man-days required per line for retaining optimum productivity under harmful algal bloom restrictions (extra man-days per line). =[extra man-days per line] * [average wage in the area] Gasoline costs Based on the assumption that gasoline consumption is positively connected to higher automation investments (bigger water vessels). It depends on the current gasoline prices, as well as on the frequency of using the water vessel. The number of days the water vessel is used is a function of the number of cultivation lines and of the frequency and duration of the harmful algal bloom’s occurrence. = [gallons needed per working day]*[number of working days] Legality costs Licensed establishments pay an annual perquisite of €1500/year. Establishments with expired licenses pay on average a fine equal to €10,000/year.