Arctic Science Journeys
Radio Script
1997

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Ballast Aliens
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STORY: When an oil tanker leaves Alaska, the weight of all that oil helps keep the ship stable. Once the ship offloads its oil at refineries in say, San Francisco or Tokyo, it then pumps seawater into its ballast tanks to help it maintain stability during the return voyage.

The problem is that sometimes more than just seawater ends up in those ballast tanks. So-called alien species--things like crabs, fish and other creatures not native to Alaska--end up in the tanks, too. When the ship arrives back in Alaska waters, the ballast water--and anything else in the water--is dumped overboard.

KOPP: "They've been referred to as floating aquariums, and that's not inaccurate. The ballast gets discharged into the receiving port and of course many of those creatures will die, but a very small portion of them will be nuisance species and have some of these detrimental affects."

That's Joel Kopp, a research coordinator with the Prince William Sound Regional Citizens' Advisory Council. The council is concerned about what tankers are dumping into Prince William Sound.

KOPP: "Because Valdez receives so much ballast water, on the order of 20 million tons a year, we are naturally concerned that we may be at risk of an invasion. There are a couple of reasons for our concern. We get so much ballast water, and the ports that we receive the ballast water from are themselves invaded by nonindigenous species. So they could easily be picked up in the ballast water from there and be deposited in Prince William Sound. Also the voyage times are short between the West Coast and here, so there's relatively little die-off. They arrive here alive."

Worldwide, invasions of alien species is a leading environmental issue. San Francisco Bay has more than 230 such species--so many that native species have virtually disappeared. Nora Foster, a biologist at the University of Alaska Fairbanks, says non-native species could cause serious environmental problems for Alaska.

FOSTER: "The green crabs that are causing problems along the West Coast could out-compete some of our smaller crabs and commercial crabs like Dungeness, and have a negative effect on that fishery. There's others that might compete with or prey upon things like urchins or sea cucumbers, where there are developing commercial and subsistence fisheries."

Earlier this year, researchers from the Smithsonian Environmental Research Center collected water samples from the ballast tanks of oil tankers. While the findings won't be ready until the fall, Anson Hines of the Smithsonian expects to see a variety of species.

HINES: "Generally speaking, from the two studies in the U.S. that have been completed to date, there are many different kinds of organisms, both plant and animal, of all major taxonomic groups, and microscopic plants. But in addition to the microscopic organisms, we also found a number of large macroscopic animals including crabs, and fish including mullet from the Mediterranean Sea which were nearly two feet long."

The Prince William Sound Regional Citizen's Advisory Council recently received funding from the University of Alaska Sea Grant Program to continue the study for two years. Researchers from the Smithsonian will take additional water ballast samples from oil tankers, and conduct tests to see if the species they find are likely to survive in the cold waters of the sound. Finally, they'll measure the effectiveness of exchanging ballast water while far at sea. The council's Joel Kopp says such research is long overdue.

KOPP: "We decided it's time to look at the ballast water because for the 20 years that tankers have been coming here, no one has done that. No one has looked to see what's arriving in the ballast water."

Some steps have been taken to reduce the chance that nonindigenous species will reach Alaska. New federal laws require tankers coming from foreign ports to exchange ballast water while far at sea, in the belief that alien species will be flushed into the deep ocean where they likely won't survive. Once back in Alaska, the tankers dump their deep ocean ballast water into Port Valdez, where likewise any species they picked up during the exchange would probably die.

But Joel Kopp says even this practice may not be enough.

KOPP: "Because even ballast exchanges are not totally effective. Not all of the ballast is exchanged and a lot of the critters just settle to the bottom of the tank in the sediment down there and never get exchanged. So they could get re-suspended and discharged into the arrival port even if the water was exchanged in mid-ocean."

At least one nonindigenous species--a type of soft-shelled clam common in the Atlantic--established a foothold in Alaska's Prince William Sound during the 1800s. Scientists want to ensure that other stowaways don't fare as well.

OUTRO: For Arctic Science Journeys, this is Debra Damron reporting from Fairbanks, Alaska.