hipping lines calling at California ports must now comply with costly regulations designed to prevent the discharge of non-indigenous marine life into the state's waters.

Under a measure that took effect Jan. 1, every vessel calling in California must engage in a process known as midocean ballast-water exchange.The regulations are a clear warning signal to the shipping industry at large, which has yet to take a cohesive position on the issue. Similar - and possibly more rigorous - rules are coming elsewhere. A federal version already is in place on the Great Lakes and the Hudson River, and Washington isn't through.

Ballast water that a ship takes on in a foreign port to trim and stabilize itself often contains aquatic species indigenous to that region. When the ballast is discharged at a U.S. port during cargo operations, the creatures are released into U.S. waters.

They often thrive. They crowd out native marine life, clog water-intake pipes and burrow into levees. The zebra mussel, introduced into the Great Lakes in the mid-1980s by vessels arriving from Europe, has caused billions of dollars of damage.

Similar problems have occurred in California, especially in the San Francisco Bay. To combat them, California now requires that vessels arriving directly from a foreign port exchange ballast in midocean to replace potentially tainted ballast water with clean water. The process is costly, though, and it requires constant monitoring.

And that's only half the equation. Shipping lines must also pay the state $600 per vessel call to fund a research program designed to find better ways to prevent the discharge of invasive species in California waters.

The Steamship Association of Southern California and the Pacific Merchant Shipping Association in San Francisco supported the ballast-exchange bill when it was revised to its current form. The original bill could have led to even more onerous requirements, such as installation of on-board and shoreside ballast-treatment plants.

The shipping organizations, however, object to the per-voyage fee. They believe a fee of $300 to $400 would be sufficient to fund a program of research and development.

The current rules are temporary. The State Lands Commission will study the issue further and publish permanent rules in April. The shipping groups will try to get the fee lowered in the permanent regulations.

But the issue goes far beyond California. Other states and the federal government, not to mention environmentalists, are concerned about invasive species. The Coast Guard in July began a national program under which vessel operators must report ballast-management practices. Midocean ballast exchange is voluntary under the program, but the policy will be reviewed in two years and could become mandatory.

Midocean exchange isn't a perfect response to invasive marine species, but nothing more effective has emerged. And unfortunately the shipping industry has yet to come up with a solid approach of its own - something it should think hard about, and promptly.

At the very least, the industry should seek a workable national program that doesn't become a profit center for the government. That would be better than a hodgepodge of programs at the state level.