The red Japanese seaweed that smells like rotten eggs is more than a nuisance this summer on the beaches of Cape Cod and Cape Ann. It also speaks to one downside of globalization: the ballast water that cargo ships take in or discharge to maintain the proper overall weight as the amount of cargo on board changes.

Scientists say the journey of this seaweed probably began decades ago in Japan or Korea, when it hitched a ride in ballast water or on oysters imported to Europe for shellfish farming. From its first detection in 1984 near an oyster farm in France, the seaweed spread over to Ireland, up to Norway and Sweden, and down to Spain and Italy. It then likely came here from Europe in ballast water. It showed up on a Rhode Island beach three years ago and now has moved up the New England coast, worrying innkeepers at the peak of the summer tourism season and lobstermen who are finding the seaweed clogging their traps. This pattern has become grimly familiar: From seaweed to zebra mussels to Asian carp and long-horned beetles, invasive species cost the nation an estimated $120 billion a year in eradication efforts, lost recreational business, and fallen property values.

This spring, the Coast Guard, in coordination with the Environmental Protection Agency, issued new rules to dramatically limit the number of live organisms in discharged ballast water. It will also require new ships built after Dec. 1, 2013, to have equipment to treat ballast water with ultraviolet light or chemicals before discharge. That is a start.

But the shipping industry lobby won a grace period for the 61,000 commercial ships based in the United States and the 9,400 foreign ships operating in US waters. Owners of the those vessels do not have to worry about retrofitting until their first scheduled maintenance dry-docking. Since well-built ships can go several years without major maintenance, it may be nearly a decade before some vessels actually comply. The schedule should be accelerated. The cost of treatment equipment has to be balanced against the damage that invasive species do to the economy in Massachusetts and elsewhere.