Mitten crab
(Source: CA
Dept. of Fish
& Game)
The flow of goods in and out of Bay Area ports is a vital part of the region's economy. However, the ships bringing these goods also discharge ballast water containing exotic, and unwelcome, marine life into San Francisco Bay. In June 1999, the Port of Oakland became the first major US West Coast port to take action against this threat by restricting the discharge of ballast water.
Ballast water is used by ships to provide stability and make the vessels easier to handle. The need for ballast water varies by type of ship, and with differing cargo and sea conditions. Ballast water is often taken on in a port or coastal region, where the water contains many organisms. It may be released at sea, along a coast or in another port. If conditions are right, the "kidnapped" organisms may find a new ecosystem in which to flourish.
In the Bay Area, the many non-native species introduced in the past few years have changed the marine environment so much that scientists despair of ever returning the Bay to its original ecosystem. New species arrive not only in ballast water, but on fouled ship hulls, and through aquaculture, bait fish shipments, and deliberate introductions of species used for food in other parts of the world or originally acquired for aquarium use. According to Andrew Cohen of the San Francisco Estuary Institute, the rate of such relocations is increasing; one study shows that between 1961 and 1995 there was one new invasion of the San Francisco Bay ecosystem every 14 weeks, and at least four species a year become established as permanent residents.
Three of these invaders, the green crab, the Asian basket clam and the mitten crab, have had the greatest effect on the Bay and Delta. Green crabs feed on the clams and Dungeness crabs which support commercial seafood operations in the region. Asian clams draw on the same food sources as native mollusks, crustaceans and small fish, but their tendency to concentrate selenium makes them a far less desirable food source than the species they have replaced. The mitten crab, which may have been deliberately introduced, clogs fish screens at Delta pumps. (So far, the Bay and Delta have not seen any sign of the zebra mussel, which now blocks water transport and purification systems along the Great Lakes and the Mississippi River. However, the mussel is moving slowly westward, spread by recreational boaters as they move from one water body to another, and has been found on boats at California checkpoints.)
One of the first lines of defense against exotic species is to cut off the supply of ballast water which transports them into the Bay. This may seem somewhat like closing the barn door after the horse has gotten loose, but it may slow the arrival of additional problem species such as the zebra mussel, and allow the ecosystem to stabilize so that scientists can determine if the impact of exotics already here can be minimized.
Reporting on the discharge of ballast water which originated outside the 200-mile Exclusive Economic Zone surrounding the United States is required by the US Coast Guard under the National Invasive Species Act of 1996. Information from the Coast Guard reports provides a basis for research efforts conducted by the Smithsonian Environmental Research Center on ballast water and invasive species. Voluntary ballast water exchange was included in federal regulations beginning July 1, 1999; exchange may be federally mandated after 2001 if Coast Guard reports indicate compliance with the voluntary program is inadequate. However, the Port of Oakland, now joined by the state, has already taken this important step toward protecting San Francisco Bay from more unwelcome new species.
The Port ordinance, which went into effect in August, was modeled on one from the Port of Vancouver, Canada. It requires ships to exchange ballast water taken up in other ports with water from deep ocean waters beyond the continental shelf. Organisms from deep water cannot survive in shallower Bay waters. Exemptions are available if such an exchange would be hazardous to the vessel or its crew, or if the ballast water to be discharged in Oakland originated in another West Coast port. Most ships entering the Port of Oakland are container ships, which already do deepwater ballast water exchange.
A state ballast water exchange law, effective January 1, 2000, covers all ships entering the Bay. It requires a joint effort by the State Lands Commission, the California Department of Fish and Game, and the California Regional Water Resources Control Board to conduct monitoring and inspection of vessels entering California ports, to research baseline conditions in waters which may be affected by ballast water discharges, to evaluate alternatives to mid-ocean exchanges, and to prepare reports for the state legislature prior to the law's sunset date in 2004. The Coast Guard and the state are coordinating reporting requirements, although the state is doing an independent compliance verification.
The Port had planned the first year of its program as an introductory period, but enforcement began in January under the state program. The state regulations also use different definitions and are somewhat more extensive in scope, creating some confusion for shippers. The Port will revise its ordinance after working with regulatory agencies which included implementation of the ordinance as conditions for Port improvement permits. Although the permit conditions will be satisfied under state regulations, the agencies may require the Port to take additional steps to mitigate the effects of ballast water discharge. The Port plans to retain the part of its ordinance which goes beyond state regulations by requiring ships to report the specific source of ballast water discharged in San Francisco Bay that originated in other West Coast ports. This information will contribute to research determining if precautions need to be taken even between one West Coast port and another.
Ballast water exchange is not a perfect solution. When ships cannot safely exchange ballast water in midocean, ballast water from one port will still be discharged in another. Even a complete ballast water exchange may not flush out all the organisms in the tank; some organisms may be left in dead spaces in the plumbing system, and in sediments at the bottom of tanks. Research is currently taking place on other options, such as treatment of ballast water tanks while underway with heat, chemicals, filtration or ultraviolet light, or treatment in onshore wastewater treatment plants before discharge. Research sponsors include the Port of Oakland, port and shipping associations, and the US Fish and Wildlife Service. Results will help form another line of defense for the Bay and Delta.
The Bay Area has already sustained major impacts from non-native species arriving in ballast water. The ballast water exchange program, first implemented at the Port of Oakland and now in effect at all the region's ports, is the first strand of what may become a complex safety net protecting the Bay and Delta from more extensive invasions.
Leslie Stewart
For more information on ballast water regulations:
Port of Oakland: Jody Zaitlin (see below); http://www.portofoakland.com/news_ballast.html
State of California (State Lands Commission): 916/574-1900; http://www.slc.ca.gov/BallastWater/default.asp
US Coast Guard: http://www.uscg.mil/hq/g-m/mso4/surveyresults.htm
For more information on invasive species:
San Francisco Estuary Institute: 510/231-9539; http://www.sfei.org/invasions.html
Smithsonian Environmental Research Center: http://www.serc.si.edu/invasions/ballast.htm
Ballast water is discharged from a ship in port. (Source: CA State Lands Commission)
May 11, 2000, 9:00 am - 12:30 pm
Elihu Harris State Building, 1515 Clay Street, Oakland; Admission is free.
Contact:
Jody Zaitlin, Port of Oakland
530 Water Street, Oakland, CA 94607
510/627-1179
jzaitlin@gw.portoakland.com