Import cargo volume at the nation's nine major retail container ports will remain below last year's levels for the remainder of the summer before seeing year-over-year gains again this fall as retailers begin to stock up for the holiday season, according to the monthly "Global Port Tracker" report released yesterday by the National Retail Federation (NRF) and consultancy Hackett Associates.

"Cargo numbers have been down this summer but that's a reflection of last year's unusual shipping patterns more than the economy," said Jonathan Gold, NRF's vice president for supply chain and customs policy, in a statement. "The economy continues to face challenges, but job growth has been steady and retailers have been adding jobs themselves as sales improve. Cargo figures for this fall clearly show that retailers are expecting a healthy holiday season."

U.S. ports followed by the Global Port Tracker handled 1.25 million twenty-foot equivalent units (TEUs) in June, the latest month for which numbers are available. That was down 2.6 percent from May and 5.0 percent from June 2010.

June's volume broke an 18-month streak of year-over-year improvement dating to December 2009, and declines continued in July, which was estimated at 1.3 million TEUs, down 5.7 percent from July 2010. August is forecast at 1.4 million TEUs, a 1.6-percent decrease from a year ago.

Rather than reflecting an economic downturn, however, the numbers are a skewed comparison against higher-than-normal numbers last summer when fears of shortages in shipping capacity caused many retailers to bring holiday merchandise into the country earlier than usual, according to the report. Actual retail sales have seen 12 straight months of growth, according to the report.

Year-over-year increases are expected to resume in September, which is forecast at 1.48 million TEUs, up 10.4 percent from last year. October is forecast at 1.46 million TEUs, up 8.0 percent from last year; November at 1.31 million TEUs, up 6.2 percent; and December at 1.18 million TEUs, up 3.0 percent.

The first half of 2011 totaled 7.15 million TEUs, up 3.9 percent from the first half of 2010, and the full year is forecast at 15.28 million TEUs, up 3.6 percent from 2010. Imports during 2010 totaled 14.7 million TEUs, a 16-percent increase over unusually low numbers in 2009.

While cargo volume is expected to increase through this fall's holiday shipping cycle, Hackett Associates founder Ben Hackett said a number of key economic indicators are raising concerns about future cargo growth.

"Industrial production in China is weak, bulk commodity imports are declining, and ports are beginning to report reduced export volumes," Hackett said in the statement. "In the U.S., we have lower private consumption, lower government expenditure, and lower indices like the purchasing managers' index. This is cause for concern because it could lead to lower growth of trade volumes."

The report covers the U.S. ports of Long Angeles/Long Beach, Oakland, Seattle, and Tacoma on the West Coast; New York/New Jersey, Hampton Roads, Charleston, and Savannah on the East Coast; and Houston on the Gulf Coast.