California Coast & Ocean

Among alarming recent arrivals in California waters is the Asian kelp Undaria pinnafitida, best known by its Japanese name, wakame. First found in Los Angeles Harbor in March 2000, by August 2001 it had been spotted as far north as Monterey Bay. Wakame is harvested as food in Japan, and is also eaten here. How Undaria came to California waters is uncertain--it is a fouling species, but its spores could have arrived in ballast water, or it may have been introduced deliberately for harvesting. A major concern is that it might interfere with, or even hybridize with, giant kelp (Macrocystis pyrifera), potentially devastating the coastal kelp forests, which are among the richest marine ecosystems. Scientists fear that if Undaria becomes established it will be impossible to control, as a single adult releases millions of spores that can lie dormant on the sea floor until conditions are right for it to grow. In Monterey Bay, boaters, divers, and other volunteers have been working to find and remove new-grown algae before they can reproduce. It may still be possible to control Undaria there, Cohen said, but he doubts that it can be eradicated in California.

Controlling ballast water may be difficult, but it's a breeze compared to trying to eliminate fouling species--plants, algae, and animals that attach themselves to boat hulls and hard substrates, natural or manmade, such as rocks and piers. "Ballast water is a solvable problem," said Cohen. "Organisms contained in a tank of water can be killed, but fouling species are in open water." It's next to impossible to police all the boat hulls in state waters, but he thinks the worst offenders are the small number of boats that stay in one place for a long time, then move slowly to another.

Boaters have always had to scrape barnacles, kelps, and other fouling species from hulls. More recently, they have also been using anti-fouling paints--based on copper and, until it was outlawed, TBT--that are toxic to these species. These paints, however, also leach toxins into the water, harming other marine life. The Department of Boating and Waterways has been encouraging boaters to find alternatives, but nothing quite as effective as copper has been found, so avoiding these paints means that more fouling species survive to wreak further damage.

Exotic species also get into coastal waters from other sources, including imported fish and seaweeds that are released from aquaria. Aquaculture operations have been a source of imported parasites and diseases that can be devastating if they escape into coastal waters. Most native abalone species are now threatened by withering disease or by a South African parasite, both introduced from abalone culture operations.

The Coastal Conservancy is now working with the Department of Fish and Game to develop a comprehensive aquatic invasive species management plan, funded by $110,000 from the California Ocean Protection Council, that will coordinate and define the roles of multiple agencies in combating invasive species in all California waters, including freshwater. This plan will be completed by May, and then open to public input during the summer. If the plan is approved by the governor and hoped-for federal funds are obtained, it should provide a much better coordinated effort that will facilitate early detection of aquatic invaders, rapid response to species that are of urgent concern, and improved monitoring of species and control efforts. It's encouraging that so many people are working to deal with marine invaders and the problems they cause, but the challenges are nearly as vast and complex as the oceans themselves.