Big Island-based technology company Cyanotech Corp. is looking for its second chief executive in just two years after ousting President and Chief Executive Officer Andrew Jacobson.

The company's board of directors removed Jacobson, but has not said why.

David Rosenthal, a Cyanotech board member since November 2000, was appointed president and chief executive officer on an interim basis until a replacement is found. Cyanotech, in announcing the change yesterday, said Rosenthal's appointment was made Saturday.

Jacobson declined comment.

Shares of Cyanotech stock dropped 53 cents to $3.86 after the announcement was made yesterday. Trading of shares was relatively heavy.

Cyanotech produces nutritional microalgae products using deep seawater drawn from off the Kona Coast.

The company in late 2007 announced that founder Gerald Cysewski had agreed to focus on new product development as chief scientific officer, and would step down as chairman, president and chief executive officer.

The move was part of a strategic shift away from processing and distributing microalgae products to a more marketing-oriented approach for enhancing the value of Cyanotech's core products, Spirulina Pacifica and BioAstin natural astaxanthin.

An executive search firm recruited Jacobson, who was hired as president and chief executive officer in May 2008 and earned $335,000 a year.

Jacobson, now 48, was a divisional president for Hain Celestial Group, a natural and organic food and personal-care products company, before he joined Cyanotech.

Rosenthal, 55, is a member of Cyanotech's audit committee, and will continue his role in that capacity while leading the company.

Most recently, Rosenthal was chief financial officer of Hickory Farms Inc., a specialty food and gift products provider. Before that, he had held chief financial officer positions with several publicly traded companies, including tea products producer Celestial Seasonings Inc.

Cyanotech, which was founded on the Big Island in 1983, has fought through the challenging economy to introduce new products and post higher profits in recent quarters.

The company said net income for the last three months of 2009 was $605,000, a record for its fiscal third quarter and up from $514,000 in the same period a year earlier.

Income for the first nine months of Cyanotech's fiscal year ending Dec. 31 also was a record, rising 71 percent to $1.6 million from $948,000 in the same period a year earlier.

Among the milestones Cyanotech Corp. cited during the last quarter were the launch of spirulina multivitamins, and the discovery of vitamin K2 in its spirulina product.