Toward Biological Integrity:
The Challenge of Alien Invasive Species

Introduction: An Ecologically Damaging
and Economically Costly Problem

Since the 1980s, the International Joint Commission has issued alerts about the threat of aquatic alien invasive species to the Great Lakes-St. Lawrence River basin ecosystem and economy.¹ Yet despite more than a decade of international attention and regional action, this "biological pollution" continues at both great ecological and economic cost.

Most citizens of Canada and the United States are probably familiar with the havoc some alien invasive species have wreaked. The chestnut blight and Dutch Elm disease, gypsy moths, Norway rats and kudzu, and, in the Great Lakes basin, purple loosestrife, sea lampreys and zebra mussels are well known examples of ecologically and economically harmful species imported either accidentally or purposely from other continents to North America. In each of these cases, damage occurred because native species and ecosystems were not capable of resisting infection, infestation, predation or competition from the alien species. In some cases, damage has been extraordinarily severe. The chestnut blight, for instance, eventually wiped out virtually all American chestnut trees across nine million acres; sea lampreys devastated populations of lake trout and other fish species in the Great Lakes.²

• Chart: Causes of Biodiversity Change in the Great Lakes during the 21st Century
  
  The introduction and spread of aquatic invasive species is expected to be one of the leading causes of biotic change in lake ecosystems during the 21st century. All of the Great Lakes are experiencing such impacts from zebra mussels, sea lamprey, round gobey, and the spiny waterflea. Sala et al., 2000.

Invasive Species

Researchers widely believe that the costs of biological pollution from alien invasive species are both massive and rising, with costs to native ecosystems, natural resources, fisheries and agriculture estimated in one study to reach $137 billion per year in the United States alone, including but not restricted to aquatic species.³ In contrast, 1992's Hurricane Andrew, the single most expensive natural disaster in United States history, cost insurers only a small fraction of that amount, about $16 billion (or $20 billion in 2002 dollars).⁴ This suggests the true costs of biological pollution in the U.S. alone equal multiple Hurricane Andrews every year.

In the Great Lakes, costs for treatment and control of zebra mussels alone reach several billion dollars annually.⁵ The Great Lakes Fishery Commission reports that sea lamprey control, assessment and research cost $13.5 million in 2001.

The damage is at least as much environmental as economic. Since biological pollution's effects are often irreversible, any future introductions of alien invasive species could permanently harm the biological and ecological diversity of the Great Lakes, the world's largest surface freshwater ecosystem. Yet, despite some efforts to reduce the potential for future introductions of harmful alien species, the threat remains. This serious problem continues at least in part because individuals or businesses responsible for introducing alien invasive species have never borne any significant part of the often extremely high costs. The high costs instead have been transferred to government resource agencies and the taxpayers who support them, to private and public utilities, and to industrial and private users of natural resources.

Current rules and practices are not solving the problem

Today, the Great Lakes - St. Lawrence River basin ecosystem is home to more than 160 non-indigenous fish, invertebrates, plants, parasites, algae and pathogens.⁶ Additionally, many introduced species have likely gone unnoticed.⁷ The number of recorded introductions of alien invasive species increased throughout the 20^th century, from 40 in the first half to 76 during the latter half. And despite increasing awareness of the risks, the 1990s saw no discernable improvement. In the 1990s, 15 alien species found their way into the ecosystem, a number of introductions essentially unchanged from the 1980s (15), the 1970s (17), and the 1960s (15).⁸

• Chart: Great Lakes Invasions
  
  The number of recorded introductions of alien invasive species from all sources continued to increase throught the 20th century. Riccardi 2001.

Nonindigenous Animals Established in the Great Lakes Drainage Basin Since the mid-1980s

Ricciardi and MacIsaac 2000.

A number of sources, or vectors, can transmit alien invasive species into the ecosystem including aquaculture, canals and diversions, baitfish disposal, intentional introductions, recreational boating, and ship fouling.⁹ The most significant vector is ballast water ­ the water, entrained solids and sediment and, all too often, living species, taken in and discharged by ocean-going ships.¹⁰ Some regulations and guidelines are now in place to attempt to control alien species introduction from ballast water exchange from ships moving into the Great Lakes through the St. Lawrence. Yet, as we achieve better control of ballast water, other vectors must be seriously addressed to stop the invasion of species such as the Asian carp.

Discharge of Ship Ballast Water

Ballast water is used to stabilize ships and maintain trim. Some transoceanic ships may carry up to 150 million liters of ballast water. Biota can be loaded with ballast water and discharged during routine ballast operations.

In 1993 the U.S. Coast Guard issued regulations requiring ships bound for the Great Lakes from beyond 200 miles off the U.S. coast to take steps to reduce risks from alien invasive species in ballast water. Ships now are required to exchange ballast water on the high seas, retain the water on board, discharge to an approved reception facility, use an environmentally sound alternative (which could include such steps as treating the water), or under extraordinary conditions, exchange ballast water within an alternate area. Canada is currently drafting regulations.

Compliance with these regulations and guidelines has been nearly 100 percent.¹¹ Yet this high level of compliance alone is far from 100 percent effective. Research published in 1999 showed that a population of at least one alien invasive species, Ceropagis pengoi (a waterflea), found its way into Lake Ontario, apparently transferred by ballast water, even after the ballast water exchange regulations were put in place.

One major flaw in the process appears to be that ships declaring "no ballast on board" (NOBOBs) are exempt from the regulations, even though these ships can harbor alien invasive species in residues of previously discharged ballast water and therefore represent a serious, continuing biological pollution risk to the ecosystem.

• Chart: Great Lakes Inbound Ships
  
  NOBOB ships, currently exempt from regulations requiring ballast water exchange at sea, make up about 70 percent of the ships entering the Great Lakes system.
  Colautti et al 2002.