LONDON (AFP) - British oil group Shell said Wednesday its net profit plunged by 62 percent in the first quarter, to 3.488 billion dollars (2.645 billion euros), with production down due to the weak economic climate.

The figure excludes changes in the value of oil held in stock, a key measure for the industry, and compared to net profit totalling 9.083 billion dollars in the first quarter of 2008.

On a "current cost of supplies" basis, which adjusts for changes in the value of oil held in stock, Shell reported earnings of 3.297 billion dollars, down 58 percent from the same quarter last year.

"First quarter 2009 performance was affected by the weaker global economy, with a challenging upstream and downstream business environment," Royal Dutch Shell's chief executive Jeroen van der Veer said in an earnings statement.