The surplus of tankers competing to ship 2 million-barrel oil cargoes from ports in the Persian Gulf expanded for a second week, according to a Bloomberg News survey of shipbrokers.

There are 18 percent more very large crude carriers seeking charters over the next 30 days than probable shipments in the world’s largest cargo-loading region, the median in the survey of four shipbrokers and two owners showed today. The excess last week was 13 percent.

The VLCC fleet’s capacity expanded 39 percent in the past five years, according to data from IHS Fairplay, a Redhill, England-based maritime research company. Seaborne crude-oil imports will average 38.4 million barrels a day this year, 0.5 percent more than in 2008, according to Clarkson Plc, the world’s largest shipbroker.

Freight rates for VLCCs on the benchmark route to Asia from the Middle East slumped 0.5 percent yesterday to 42.06 Worldscale points, the sixth consecutive decline, according to figures from the Baltic Exchange in London. The Worldscale rate equates to earnings for owners of $16,282 a day for the vessels, according to the bourse’s calculations.