Underwater Aliens

Seth Cool is program manager for the Washington Invasive Species Coalition (http://www.invasivespeciescoalition.org). He lives in Bellingham’s York neighborhood.

In March 2004, as she was scuba diving at the Edmonds underwater park, Kinsey Frick spotted something she had only seen on the East Coast. A mustard-colored spongy creature coated the bottom of a sunken boat. Kinsey suspected this was Didemnum sp., an invasive sea squirt native to Europe that has infested the East Coast. It had never before been found in Puget Sound. In our waters, this aggressive critter that can create thick mats, has no known predators and may smother native aquatic life.

While no one is sure how Didemnum sp. arrived here, scientists believe it was likely introduced by ballast water. Large ships use ballast water for stability; when they unload, cargo ships pump aboard huge quantities of ballast water to avoid capsizing. Everything one might find in seawater—from bacteria to fish, sediments to plankton, and copepods to mussels—can get sucked up, transported across oceans and then introduced to new areas when ballast water is discharged. These aliens sometimes survive and flourish in their new environment.

Unfortunately, introductions from ballast water have had profound effects on fish and other wildlife. As with Didemnum sp., new species with no local predators can become invasive and wreak havoc on the marine environment as they displace or smother other wildlife, steal their food or feast on natives. And once introduced, aquatic invaders have few barriers against spreading. They are hard to detect and are virtually impossible to eradicate, becoming what some call “pollutants without half-lives.”

Prevention of introduction is key and ship operators have ways to reduce the risk of introducing exotic marine species. Some ship operators have found ways to hold their ballast water. Ballast water uptake can be avoided in areas with rich amounts of aquatic life, such as estuaries. Most ships are able to conduct exchange at sea, flushing their ballast tanks with relatively benign seawater. And entrepreneurs are racing to manufacture systems that sterilize ballast water.

Ships have been introducing invasive species for centuries—rats were spread around the world on early voyages. Sailing ships used rocks or sand as ballast, and are thought to have introduced the seeds to North America of wetland invader purple loosestrife.

Today, less-polluted ports and faster ships with less time between ports have led to more favorable conditions for stowaway critters. Less toxins in the ballast water, and shorter travel time increases the chance that organisms will survive the relocation process. The huge increase in global trade has increased the amount of ballast water being transported and discharged. Every hour, an average of more than two million gallons of ballast water is released into U.S. waters. (Source: West Coast Ballast Outreach Project, California Sea Grant Extension Program.)

San Francisco Bay harbors at least 234 introduced species, and the rate of invasion is increasing. From 1851 to 1960, the average rate of invasion of the bay was one new species every 55 weeks; from 1961 to 1995 it increased to one new species every 14 weeks. In the benthic (sediment) community invasive organisms comprise up to 99 percent of the biomass.

To reduce the likelihood of invasive species introductions, the U.S. Coast Guard requires that ships entering from outside the U.S. exchange their ballast water at sea with clean ocean water. But federal law ignores ships traveling along the coast—say from San Francisco to Seattle. So to prevent the spread of invasive species from port to port, the Washington Department of Fish and Wildlife (WDFW) requires ocean exchange for these coastwise ships too.

The Washington Department of Fish and Wildlife tracks ship operators’ ballast water management, and randomly boards vessels to take samples and check ship logs. This program is funded on a shoestring budget, but has been remarkably successful at helping educate ship operators and encourage better practices. Container ships have been remarkably successful at exchanging and holding their ballast water, while ships that carry bulk commodities such as grain or steel, etc., and petroleum tankers appear to have a harder time complying with the law.

Just three years ago, the largest and second-largest dischargers of dangerous ballast water in Washington were at Cherry Point and March Point. Ships that transport petroleum products from refineries near Bellingham and Anacortes to California, return with ballast water. Several of these ships could not conduct exchange, and were discharging dangerous ballast water right here in Whatcom County.

Crowley Maritime operates a few of these ships, and has worked hard to install new pumps on some of their vessels. Their efforts were a major success—the ballast water in these ships is now exchanged at sea with clean ocean water. U.S. shipping still operates a handful of older ships and barges, which call on Cherry and March Points and have trouble exchanging at sea. Some of these ships are due for replacement, and British Petroleum is requiring in their contract that new ships calling on their Cherry Point refinery have the ability to conduct exchange and have space to install future treatment systems.

From a statewide prospective, WDFW’s ship boarding program is very successful—discharges of un-exchanged ballast water have been reduced from 47 discharges in the first six months of 2004 to just 10 in the first six months of 2005. The risk of invasion appears to be going down!

In the long-term, ballast water exchange will likely be replaced with treatment systems which sterilize ballast water. Exchange is extra work for the ship’s crew, can be dangerous and is not always effective.

Entrepreneurs and engineers have tried for years to design ballast water treatment to protect our marine environment with inventions ranging from heat, ozone, UV light, centrifuges, to biocides. But some ships carry more than one million gallons of ballast water, which must be pumped aboard or discharged quickly. Ships and the marine environment are notoriously harsh on equipment, and the system must be effective at killing unwanted organisms in the ballast tanks but not harming native aquatic plants and animals when the ballast water is discharged.

Fortunately, there are several promising treatment systems moving forward. One such system, called “BalPure,” uses hyperchlorite technology, which has been used in the maritime industry for decades. This system uses electricity to isolate chlorine and bromine naturally present in seawater. The ballast water is dechlorinated just before discharge. BalPure has done remarkably well in lab tests and will be reviewed for approval by Washington state before the end of the year. NEI Treatment Systems, LLC, is marketing a chemical-free “venturi oxygen stripping” system which deoxygenates ballast water. Unfortunately, it works slowly, so will not likely be a solution for ships operating along the West Coast. Another company, called Ecochlor, has a test system operating on a ship in the Atlantic and just installed a second system aboard a ship that frequents Hawaii. Ecochlor uses chloride dioxine to sterilize ballast water.

Didemnum sp., the invasive species of sea squirt, has since been discovered in Hood Canal. It is likely here to stay. But with a mix of luck, continued funding of Washington Department of Fish and Wildlife’s ship boarding program, and if shipping companies abide by the law and work to install treatment systems, we will have fewer invasions in the future. §