(Sharecast News) - Shares in Costain eased in morning trading on Wednesday after the construction and engineering group unveiled a decline in revenues and profits and announced that its long-standing chief executive was stepping down.Total revenues for the year to 31 December were £1.49bn, down from 2017's £1.73bn. Underlying operating profits rose 7% to £52.5m, but pre-tax profits nudged lower, to £40.2m from £41.8m.Costain attributed the revenue decline to "a lower level of capital project activity in line with our strategic change in mix of activities" during the year. Chairman Paul Golby said 2018 had been "an another strong performance for Costain, with further growth in underlying profit at enhanced margins".The group, which specialises in energy, water and transportation infrastructure, also remained confident about the current year, with the order book now at £4.2bn, 90% of which is repeat orders. Chief executive Andrew Wyllie said: "With a clear strategy, strong balance sheet and a record order book, the business is in an excellent position deliver further growth in the future."However, cautious investors remained less sure, sending the shares 4% lower to 382.5p by noon GMT.Costain also announced that Wyllie was leaving the company, after 14 years at the helm, to pursue a portfolio of non-executive career. He will be replaced by Alex Vaughan, managing director of the group's natural resources division.Golby said: "[Wyllie] leaves the group in good health, the result of the growth strategy which he and his colleagues have been implementing for the last 14 years."