Cleanseas Tuna says it can’t explain a 61 per cent rise in the value of its shares in the last week.

Market operator ASX has asked the South Australian tuna farmer and research company if it knows of any reason why its shares have moved from 2.8 cents on August 29 to a high of 4.5 cents on Thursday.

But the company says it is not aware of any information not already released publicly that could explain the share price rise.

Cleanseas released its annual report for the 2012/13 financial year on Wednesday, and posted an annual loss of $34.5 million for 2012/13 on August 15.

Cleanseas shares were at 4.0 cents at 1528 AEST.