Efforts to protect the nation's thousands of miles of vulnerable coastlines from terrorists are steaming ahead, but much more remains to be done, and the costs will likely be shouldered in part by private industry, a Coast Guard admiral told an international conference on maritime security Monday.

"Prior to 9/11, 2 percent of our Coast Guard budget was dedicated to port security; it's now about 25 percent,'' Rear Admiral Kevin Eldridge told a conference of shippers, insurers, port authorities and security consultants at the California Maritime Academy in Vallejo. Eldridge is commander of the Coast Guard's 11th District, which includes all California ports. "It's a big job. This country has 95,000 miles of coastline, including our seacoast, the Great Lakes and rivers, and 361 ports.''

Eldridge did not put a total price tag on the required changes, but indicated the amount would be large. The Coast Guard, he said, is planning computer upgrades, new vessels and other changes through 2012. Ports and private companies also will need to make improvements to keep up with Washington's changing regulations and new security systems.

The federal government, Eldridge said, is allotting "$300 million to $400 million a year in grants to companies and public entities for port security.'' But, he added, without supplying specifics, "The philosophy is that the (maritime) industry needs to bear the brunt of the cost.''

Eldridge spoke on the second day of a three-day conference sponsored by the California Maritime Academy and the Admiral Makarov State Maritime Academy in Russia.

Former Defense Secretary William Perry, who served under President Bill Clinton, also spoke, calling the nation's ports "a front line in our global war against terror.''

The conference, which ends today at the California Maritime Academy's waterfront campus, was set up to scrutinize security needs in the post-Sept. 11 era, organizers said.

Following the 2001 terrorist attacks, concern grew that terrorists could stage future attacks by smuggling dirty bombs, toxic chemicals, volatile fuels or other weapons into the United States in cargo containers and in the holds of the 9,500 U.S. ships and 8,000 foreign vessels that visit this country every year.

Such fears prompted Congress to pass the Maritime Transportation Security Act in 2002. Since then, the Coast Guard has been moved from the Department of Transportation to the newly created Department of Homeland Security and its budget has been pumped up from $5.8 billion in 2001 to $8 billion this year.

Additionally, cargo shippers are now required to furnish U.S. ports with detailed information about cargo, crew and passengers 96 hours before making landfall, up from 24 hours before the attacks.

But reinventing U.S. maritime security is far from a finished process, acknowledged Eldridge, who said that all 144 major U.S. ports will be required to have new security plans in place by July 1. The Bay Area's three major ports -- Oakland, Alameda and Richmond -- have had their plans approved, he said, but about half of the nation's ports have yet to be certified as compliant by federal authorities.

Upgrading port security has so far proved expensive, and it is not always clear where the money to cover mandatory security upgrades is going to come from.

The Port of Oakland, which handles more than 90 percent of the Bay Area's seaborne cargo, asked the federal government for $28 million in 2003 for perimeter security and other projects but landed only a $4.8 million grant from the Transportation Security Administration. Similarly, Oakland asked for $47 million last year to install a surveillance system at its rail links but got what port spokeswoman Marilyn Sandifur said was "under $1 million'' to jump-start the system, which will total $59 million.

Addressing port and security officials from as far away as Australia and the United Kingdom, Perry praised the U.S.-led invasions of Afghanistan and Iraq as brilliantly executed. "But those wars are far from over,'' he said.

Perry characterized the war on terror as overly ambitious and diffuse, saying the United States must focus on preventing catastrophic attacks by key groups such as al Qaeda, while concentrating on underfunded homeland security fronts such as the nation's seaports.

"The Coast Guard can't do it alone,'' Perry said.