News broke last month that a solitary bloody red shrimp (hemimysis anomala), an aquatic invasive species not found before in Lake Superior, was discovered in the Twin Ports Harbor ("Worries of a new invasive species," February 20). With ship ballast tanks being the top means of moving invasive species across the globe and around the Great Lakes, this news is disappointing but not a surprise.

This finding is a stark reminder of the unknowns floating around in ship ballast tanks waiting to be emptied in ports around the region. Bloody red shrimp were brought into the Great Lakes in the ballast tanks of oceangoing vessels and first discovered in 2006 in Lakes Michigan and Ontario. These tiny critters were added to the list of more than 180 aquatic invasive species found in the Great Lakes, causing irreparable ecological harm. Aquatic invasive species also cause more than $200 million in economic damage annually to the region.

The shipping industry continues to claim success in stopping aquatic invasive species with the 2006 implementation of "swish and spit," a rule requiring oceangoing ships to swish saltwater around ballast tanks and dump it before entering the freshwaters of the St. Lawrence River. The theory is that saltwater kills off any species that might live in Great Lakes freshwater; however, some potentially harmful species can tolerate higher salinity, or can survive the treatment while in a dormant phase.

This practice is necessary, but it is not sufficient to keep aquatic invasive species out of the Great Lakes. Installing technology on board ships to clean up ballast tanks is the most effective way to prevent new invasive species introductions into the Great Lakes.

The U.S. Environmental Protection Agency and the U.S. Coast Guard have protections in place that require shippers to install ballast water treatment technologies on their ships to protect the Great Lakes from the introduction and spread of aquatic invasive species. This is especially important for Lake Superior, which has far fewer of these unwanted pests than the other more industrialized lakes to the east. The bloody red shrimp is just one example. Onboard water treatment can effectively stop the transfer of many problem invasives from other Great Lakes to our cleaner Lake Superior.

Unfortunately, the federal rules that protect the Great Lakes are under attack. Shipping industry lobbyists in Washington, D.C., are currently pushing the commercial vessel incidental discharge act (S. 168 and H.R. 1154). The bill would significantly weaken ballast water cleanup rules, expose Lake Superior and all the Great Lakes to new aquatic invasive species, and expedite the movement of existing nonnative species across the Great Lakes.

Industry lobbyists on Capitol Hill are working hard to add the bill as a rider on other funding and program authorization bills. We have joined conservation groups around the region and across the country in opposing it.

It's really straightforward. In Minnesota, anglers now know they need to clean and drain their fishing boats when moving between water bodies. It's not an easy task and it takes time. But that's how we protect our water. It's only fair that large domestic and international shippers who make profits by moving goods via our lakes play by the same rules.

The finding of a bloody red shrimp in the Twin Ports is a stark reminder of what's at stake. Lake Superior is an important source of drinking water, an economic driver, and part of Minnesota's cultural fabric.

Many members of Minnesota's congressional delegation have fought hard to protect this important resource and strongly supported programs like the Great Lakes Restoration Initiative, which provides vital funding for restoration projects. Being a Great Lakes champion also means standing up against powerful interest groups like the shipping industry when needed. We urge our elected officials in Washington to fight for Lake Superior by opposing the vessel incidental discharge act.

Steve Morse is executive director, Minnesota Environmental Partnership. Molly Flanagan is vice president, policy, Alliance for the Great Lakes.