(Corrects to net loss from net profit in fourth paragraph)
SINGAPORE, March 1 (Reuters) - Shares of Singapore-listed Oceanus Group Ltd fell as much as 11.5 percent to a three-week low after the abalone breeder's fourth-quarter net loss widened on a fair value loss of 371.2 million yuan ($59 million) in biological assets.
By 9:40 a.m. (0140 GMT), Oceanus shares were down 9.6 percent at S$0.094, underperforming the broader Straits Timex Index which was 0.4 percent higher.
In the fourth quarter, Oceanus had a caged abalone population of 134.2 million, down 25 percent from a year ago. Many of the abalones in the existing population were also of poor quality and were unprofitable to grow further, Oceanus said.
The firm posted a net loss of 502.6 million yuan for the three months ended December, compared with a 29 million yuan loss a year earlier.
Oceanus said that following three quarters of disappointing results in 2011, largely due to unacceptably high mortalities and operating costs, the board of the group removed the then CEO and legal representative, Yu De Hua, to make way for a management change and restructuring. ($1 = 6.2936 Chinese yuan) (Reporting by Eveline Danubrata)