Jellyfish cause a range of problems: they sting beach vacationers in the summer, block nuclear power plant intakes (thus disrupting the supply of electricity), decrease fishery catches, cause fishing activities to be delayed, decrease product value, and damage fishing gear. This study gauged the types and amount of damage directly caused by jellyfish. Using jellyfish monitoring data, the decreases in catch and product value for each fishery type as well as the estimated damage to each fishery type caused by jellyfish were evaluated. The results showed that the decrease in catch ranged between 6.5 and 33.7 %, and the decrease in product value ranged between 6.8 and 25.3 %, depending on fishery type. The annual direct damage caused by jellyfish was estimated to be between US$ 68.2 million and US$ 204.6 million. This corresponds to a minimum of 2.1 % and a maximum of 25 % of the annual production value, demonstrating that jellyfish cause considerable damage to the fishing industry.