Aquatic Nuisance Species and Ballast Water Management

Halting the Bioinvasion of American Waterways

Dave Cooley, GHPB

Lawmakers continue to tackle the challenge of regulating ballast water management to protect U.S. rivers, lakes, and waterways. Recently a federal appeals court in New York ordered the government to rewrite its rules regulating the discharge of ballast water by ships. The ruling was a result of a lawsuit against the Environmental Protection Agency’s 2013 Clean Water Act Vessel General Permit brought about by the National Resources Defense Council, Northwest Environmental Advocates, the Center for Biological Diversity, and the National Wildlife Federation.

On October 5, 2015, the U.S. Court of Appeals 2nd Circuit ruled that the Environmental Protection Agency (EPA) acted arbitrarily and capriciously when issuing regulatory stipulations of the Vessel General Permit (VGP). While not vacating the VGP, the Court remanded the issue to the EPA in order for it to consider alternatives with regard to referencing the International Maritime Organization (IMO) Standard utilized for Technology‐Based Effluent Limitations (TBEL), failing to consider onshore treatment for ballast water, failing to establish numerical standards for both TBEL and Water Quality‐Based Effluent Limitation (WQBEL), inappropriately exempting vessels plying only the Great Lakes (Lakers) built before 2009, and stating TBEL and WQBEL monitoring and reporting requirements that were inadequate to guarantee compliance and therefore not in compliance with law.

The EPA’s response to these issues, given the magnitude of the flow of waterborne foreign trade involving the U.S., could result in possible modifications to the existing IMO Convention for the Control and Management of Ship’s Ballast Water and Sediments.
Aquatic nuisance species (ANS) are non-native aquatic and terrestrial organisms artificially introduced into new habitats throughout the world. These non-indigenous species can dominate native species by spreading diseases or parasites, rapidly multiplying in the new environment, or simply out-competing native species for existing resources. As a result, ANS produce harmful environmental and economic impacts on native aquatic ecosystems and the human use of these aquatic resources. The most recent estimate offered by the Aquatic Nuisance Species Task Force suggests the economic cost of the damage inflicted by ANS is about $137 billion annually.
The first notice of a non-indigenous invasive species in the U.S. was the zebra mussel, native to the Caspian and Black Seas. The zebra mussel arrived in Lake St. Clair, a freshwater lake near Detroit, Michigan, in the ballast water of a transatlantic freighter in 1988. The zebra mussel spread to all five neighboring Great Lakes within ten years and has now invaded most waters east of the 100th meridian.
Congressional Action
In response to the invasion of zebra mussels, Congress passed the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 (NANPCA). NANPCA established the federal Aquatic Nuisance Species Task Force to work closely with lower levels of government to address the problems with zebra mussels. In addition, to prevent continued introduction of zebra mussels, it required all ships entering the Great Lakes to exchange ballast water in the open ocean before arrival. The ballast exchange process is discussed in more detail below.
Six years after passing NANPCA, additional harmful ANS were found across the country. Congress moved to expand the original act by passing the National Invasive Species Act of 1996 (NISA). Through NISA, the control of invasive species moves beyond zebra mussels and ballast water, although those two issues remain high in importance and priority. Two key ways that NISA updated its predecessor, NANPCA, include requiring all ships entering the U.S. to exchange their ballast water outside the 200-mile U.S. Exclusive Economic Zone and expanding the geographical scope to include areas outside the Great Lakes region.
Implementing these congressional actions, in 2012, the Coast Guard issued final ballast water regulations pursuant to NISA, as well as guidance offered by an IMO Convention on ballast water management adopted in 2004. Further supporting this effort, the EPA issued a VGP under Clean Water Act authority for controlling all discharges for ships, including ballast water — initially in 2008 and again in 2013.


Ballast water exchange process. Diagram by MaxxL is licensed under CC BY SA 3.0.

Ballast Water
In order to provide adequate stability to a vessel at sea, ballast is used to weigh the ship down and lower its center of gravity. This is accomplished by pumping seawater into specially designated tanks aboard ships known as ballast tanks. Depending on the type of vessel, the tanks can be double bottom (extending across the breadth of the vessel), wing tanks (located on the outboard area from keel to deck) or hopper tanks (occupying the upper corner section between the hull and the main deck). These ballast tanks are connected to pumps which can pump water in or out as necessary to accommodate stability requirements of the ship.
Depending on the amount of cargo aboard, these tanks are filled to add weight necessary to the ship to achieve the required stability. Also, once cargo has been discharged, ballast is added to improve the ship’s stability during the ensuing voyage to the next port (the “ballast” voyage) in order to load the next cargo.
Ballast Water Exchange
While pumping ballast aboard after cargo discharge or to improve stability, a ship could be unintentionally transporting aquatic species from one part of the world to another. By conducting a ballast water exchange in mid-ocean, the objective is to flush any hitchhiking aquatic species in the ballast tank and replace it with water free of any foreign aquatic species. While this process is generally effective, a ballast water exchange will not clear the entire ballast tank. Additionally, should the ship encounter inclement weather during the voyage, conditions may not permit a safe exchange of ballast water. For a detailed review of the topic, read the 2010 Marine Environmental Research article, “Brine-induced mortality of non-indigenous invertebrates in residual ballast water,” by Bradie, J., et al.

zebra mussels

Zebra mussels; Photo Courtesy of U.S. Fish and Wildlife Service

Types of Aquatic Nuisance Species
Zebra Mussels
In 1988, zebra mussels (Dreissena polymorpha) were found in Lake Erie and quickly spread to all the Great Lakes. Zebra mussels are still found today in each of the Great Lakes, as well as throughout the major navigable rivers in the eastern part of the United States. Recent reports indicate that this species has spread to California.
The zebra mussel most likely made its way from its native western Russia to North America through the release of ballast water from cargo ships traveling from the Black Sea to the Great Lakes. It spread further by being carried through the lakes and connected waterways via recreational and commercial traffic. The zebra mussel’s ability to disperse is enabled by its travel flexibility. In the larval stage, zebra mussels float along passively. In the adult stage, zebra mussels securely attach themselves to recreational boats that then travel overland and launch in other lakes and streams, thus spreading the non-indigenous species to other bodies of water.
Zebra mussels are most disruptive in two ways. First, they colonize and clog water supply pipes, thereby restricting water flow for systems such as cooling, fire-fighting, and hydroelectricity. The economic repercussions of this type of species invasion can be devastating. Second, zebra mussel invasions can deplete food sources in aquatic ecosystems. Zebra mussels are filter feeders consuming microorganisms, and they do so at very fast rates. Eliminating that food source from the bottom of the food chain can be dangerous to the survival of native species. The spread of the non-indigenous zebra mussels have greatly decreased the numbers of native mussels in Lakes St. Clair and Erie, species which now may be at risk for extinction.


Eurasian ruffe; “Gymnocephalus cernuus in Pärnu River Estonia” by lifar, licensed under CC BY SA 3.0;

Eurasian Ruffes
The Eurasian ruffe (Gymnocephalus cernuss) is another aquatic nuisance species that spread to the Great Lakes, Wisconsin, and Michigan, after first being discovered in the St. Louis River Estuary of the Duluth-Superior Harbor in 1986. Originally from southern Europe, the ruffe is also believed to have arrived in North America through the release of ballast water from foreign ships traveling to the Great Lakes.
The Eurasian ruffe, an extremely aggressive species of small spiny fish, produces 200,000 eggs in the first batch and 6,000 eggs in later batches. It is able to thrive in a number of different habitats where waters range from fresh to brackish and in water depths of 9 inches to 280 feet. As a fierce competitor for food sources, it feeds on plankton, bottom-dwelling insect larvae, and sometimes fish eggs. One advantage that the ruffe has over native species is better eyesight in dark conditions, allowing it to consume more food and at a quicker rate. The ruffe is now considered a dominant species in Lake Superior and the St. Louis River Estuary, and native fish species are becoming compromised.
Early efforts to control the ruffe populations attempted to introduce predator species; however the predators preferred native fish. Current management strategies are centered more on regulating ballast water discharge, as well as focused programs for identifying, monitoring, and netting the ruffe.

mitten crabEriocheirSinensis1

Mitten crab – “Chinese mitten crab” by Christian Fischer, licensed under CC BY SA 3.0.

Mitten Crabs
Mitten crabs (Eriochir sinensis) from China were first sighted in San Francisco Bay in 1992 and are suspected of being purposely introduced to initiate a fishery. Like other invasive species, the mitten crab is an ecological competitor that threatens the availability of food for native species. Although the current geographic range of the mitten crab is limited to Northern California, it is expected to migrate northward toward the states of Oregon and Washington. In addition, mitten crabs have been found in Chesapeake Bay, Delaware Bay, and the Hudson River.
The Chinese mitten crab also poses various threats to humans. First, they can damage the nets of commercial fisheries and clog water pipes. Second, mitten crabs tend to burrow, which can adversely affect the integrity of banks and levees. Lastly, they are a vector for the disease Asian lung fluke.
The ANS Task Force website shows additional species of concern, which can be viewed at:



Shipping Activity:
A key reason for this increased invasion of aquatic nuisance species is the dramatic increase in the worldwide seaborne trade. According to the United Nations Conference on Trade and Development (UNCTAD), between 1970 and 2014, world seaborne trade increased by 3.7 times from 2.6 billion metric tons to 9.8 billion metric tons. Nearly half of that increase has occurred since 2000.
Additionally, the world merchant fleet has grown 2.6 times since 1970; rising from 672 million metric tons to over 1,749 million metric tons in 2014. Bulk carriers followed by oil tankers have experienced the most prevalent growth, and both vessel types travel in ballast a significant portion of the time.
With regard to flag registration, ships flying flags from the Americas and Asia have shown the most growth, with Oceania rising somewhat significantly over the last few years. Countries in Africa and Europe continue to lose flag registrations.
U.S. Ballast Water Exchange or Treatment Regulations
The U.S. Coast Guard and the EPA have issued specific regulations with regard to the discharge of ballast water within U.S. waters. While each has its nuisances, the regulations have generally been harmonized not only with each other, but also with the IMO Convention for the Control and Management of Ships’ Ballast Water and Sediments.


World Merchant Fleet - ship type

World Merchant Fleet - ship flag

To summarize the regulations: the master, owner, operator, agent, or person in charge of a vessel equipped with ballast tanks operating in the waters of the United States must employ one of the following ballast water management methods:

  • Install and operate an approved ballast water management system (BWMS);
  • Use only ballast water from a U.S. public water system;
  • Perform complete ballast water exchange in an area 200 nautical miles from any shore prior to discharging ballast water, unless the vessel is required to employ an approved BWMS; or
  • Discharge to a facility onshore or to another vessel for purposes of treatment, which ensures that any untreated ballast water is never discharged into waters of the United States.

This does not authorize the discharge of oil or noxious liquid substances (NLS) in a manner prohibited by United States or international laws or regulations. Ballast water carried in any tank containing a residue of oil, NLS, or any other pollutant must be discharged in accordance with applicable laws and regulations.
A manufacturer whose BWMS has been approved by a foreign administration pursuant to the standards set forth in the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, 2004, may request in writing for U.S. authorities to make a determination that their BWMS is an alternate management system (AMS). These standards dictate the maximum quantities of organisms per volume of water that can remain in discharged ballast water.
The appeals panel left the EPA’s Vessel General Permit in place until the EPA produces a new one. As the panel set no deadline, it is uncertain as to when – or if – new regulation will be issued. The existing VGP expires in 2018, and the EPA must choose between revamping the VGP, asking the U.S. 2nd Circuit for a rehearing of the case, or seeking Supreme Court review of the 2nd Circuit’s decision. Whatever the course of action, significant challenges await for establishing U.S. environmental regulations that effectively yet pragmatically apply to the global shipping industry.

  • Date January 15, 2016
  • Tags January 2016