The deepwater Gulf of Mexico remains a world-class resource potential, but competition from onshore unconventional resources has diminished the energy industry’s enthusiasm for the region, an analyst says.

Bill Marko, managing director Jefferies & Co. Inc., said the number of bidders for leases in the deepwater Gulf of Mexico has fallen 30% from March 2010 to June 2012 for at least two reasons.

Marko, speaking at Hart Energy’s recent A&D Strategies and Opportunities conference in Dallas, said GoM deepwater leasing and drilling activity has traditionally risen and fallen with changes ...