Charles Stanley has upgraded James Fisher & Sons from hold to add, after its interim results highlighted the "continued attraction of the group's specialist niche marine services offering."The Asia-focused marine services firm reported last week that revenues rose 12% and normalised pre-tax profits increased 5% in the six months ended 30 June. Diluted earnings per share (EPS) climbed 11%.While the broker has kept its profit forecasts unchanged at £29.4m (implying an increase of 8% year-on-year), it has raised its EPS estimates to factor in a lower tax charge of 20%, compared with 23% the year before."Our prevailing price target of 570p was based upon peer group valuation applied to forecast FY2010 EPS of 42p. On the same basis, applying a peer group multiple to the forecast FY2011 EPS of 47p generates a target price of 587p, upside of 10%." By 10:23 on Tuesday, the shares were 1.22% higher at 539.50p.BC