Aquaculture specialist Clean Seas Tuna Ltd (ASX: CSS) admitted on Tuesday that up to 80 tonnes of kingfish were wiped out as a huge fish kill occurred on its Eyre Peninsula facility in South Australia, which the company attributed to human error.

The company revealed that the multiple deaths happened on Thursday while the fish were being bathed, routinely done in commercial fish-raising in order to counter the onset of parasites and diseases.

The incident would lead to a total loss of up to $700,000 for Clean Seas, adding more woes to the firm following the fire last year on its Port Lincoln factory that razed its stocks of feeds and equipments.

Clean Seas, which has been developing a breeding ground for bluefin tuna, saw its shares tumbling down by as much as 58 percent in February following its revelation of $14 million half-year loss.

The latest fish kill episode also spurred a 13 percent decline on Clean Seas' shares when the new broke out today.