SAN RAFAEL -- Westamerica Bancorporation (Nasdaq: WABC), parent company of Westamerica Bank, on Thursday report a 17.2 percent decrease in net income for 2013.

The bank cited continuing challenges in the operating environment for lenders for the decline. Net income last calendar year was $67.2 million. Interest and fee income decreased 14.9 percent to $167.7 million from 2012.

"Originated loan volumes stabilized at $1.5 billion; however, purchased loan volumes continued to decline," said David Payne, chairman, president and chief executive officer, in a statement. "Low market interest rates continue to pressure our net interest margin, which was an annualized 3.92 percent for the fourth quarter of 2013. Our lower-risk balance sheet continues to generate a relatively high annualized return on common equity of 11.8 percent for the fourth quarter of 2013."

Westamerica said credit quality had improved. Nonperforming assets were $35 million at the end of the year, representing a decline of 32.7 percent over the final three months of 2013. That portfolio had decreased 40.9 percent over the year.

The bank reduced its provision for loan losses to $8 million for all of 2013, versus $11.2 million in the prior year.

Average total loans were $1.96 billion at year end, compared with $2.32 billion a year before. Total assets were $4.88 billion, compared with $4.92 billion at the end of 2012.

Earnings per share were $2.50 for the year, down 14.7 percent. The bank had a 1.38 percent return on average assets versus 1.64 percent, and a 12.5 percent return on equity compared with 14.9 percent. Its net interest margin declined from 4.79 percent to 4.08 percent.

Westamerica paid $1.49 a share in dividends last year, up 1 cent from the prior year.

Shares in Westamerica Bancorporation were $53.61 at the end of trading on Thursday, down 1.97 percent.