Cyanotech Corp.’s stock soared 13.1 percent Monday to its highest level in nearly seven years after the producer of nutritional products from microalgae posted record net sales of $6 million in its fiscal second quarter.

The Kona-based company said revenue jumped 56.2 percent from $3.8 million in the year-earlier quarter with sales of astaxanthin, a dietary supplement, accounting for 60 percent of the revenue, and spirulina, another supplement, for the other 40 percent. International sales represented 27 percent of total sales.

"We’re pleased with our progress on key measures," Cyanotech President and CEO Brent Bailey said.

Net income rose 66.3 percent to $875,000, or 16 cents a share, from $526,000, or 10 cents a share, in the year-earlier quarter.

Cyanotech, which announced its earnings before the market opened, saw its stock rise 66 cents to $5.70, its highest level since Jan. 7, 2005, when it closed at $5.72.

The company’s gross profit margin, the percentage of sales left after subtracting production costs, improved to 47 percent from 43 percent in the year-earlier period.

Cyanotech’s cash and equivalent holdings in the quarter rose to $4.1 million from $783,000 a year ago.