Pandora's Locks: The Opening of the Great Lakes-St. Lawrence Seaway

11/ MELTDOWN

153 153 Foreign food webs from the Black Sea that evolved together over millions of years are being reconstructed here like Lego bricks. —Anthony Ricciardi, Canadian research scientist, 2000 11 MELTDOWN T he evening was young and there were few other boats on Lake Michigan when I joined research scientist David Jude and two of his colleagues for an unusual fishing expedition along a deserted stretch of beach in South Haven, Michigan. We ventured into the lake’s placid waters in an 18-foot Boston Whaler cluttered with fishing nets, small buoys, and weights to hold the gear in place once it was deployed. The mission was simple: trap fish in a series of gill nets to get a snapshot of what lived in the nearshore waters of the lake. Jude had performed this drill annually since 1973. It was part of a long-term monitoring program that tracked the abundance of yellow perch and alewife—and whatever else turned up—in southern Lake Michigan. Jude invited me to join his annual excursion to see if the nets would produce any surprises. Sampling fish populations in the lake had become far 154 C H A P T E R 1 1 154 less predictable in the early 1990s, after Dreissena mussels—zebra and quagga mussels—led an army of new foreign species into the Great Lakes. Sampling missions that once were routine in the 1970s and ’80s had become fraught with uncertainty. Monitoring aquatic life in the Great Lakes in the Dreissena era was a bit like the movie character Forrest Gump’s theory of life. Gump’s mother taught him that “Life is like a box of chocolates: You never know what you’re gonna get.” Scientists who studied the lakes after zebra and quagga mussels invaded faced a similar scenario. They never knew what might show up in their sampling gear. There was no telling what new species of fish, mussels, or zooplankton were lurking in these inland seas. “The lakes,” Jude said on that temperate summer evening, “are in total chaos.”1 As he steered the boat out of the Black River and into the gently rolling swells of a passing boat, Jude expressed deep concern for the future of native Great Lakes fish species and other aquatic life. Native species were wilting under the pressure of invasives, which thrived in their adopted homes and ruled like a gang of muscle-bound thugs in a neighborhood of scrawny computer nerds. Evidence of such change was found in the nets Jude’s crew used to capture fish over the course of five hours that summer night. Theirs was a modest haul for such a considerable effort. The 100-foot-wide net that the sixty-something Jude and his assistants manually dragged through the water, perpendicular to the beach, caught few fish that night. Under normal conditions, they would have hauled in hundreds of young perch. Frustrated by the meager catch, and with a half hour to kill before removing nets the crew had anchored in deeper water earlier in the evening, Jude lightened the mood with one of his trademark junk-food buffets. He broke out some Vienna mini-sausages, a bag of Doritos, and cans of Mountain Dew. The moment was classic Jude. The unconventional academic who had spent three decades studying the Great Lakes was known almost as much for his eccentricities as his expertise. To many in the scientific community, Jude was like the E. F. Hutton of Great Lakes research: When he spoke, people listened. His observations about the lakes—particularly during the biological roller coaster that followed the great mussel invasion in the late 1980s—were usually dead-on. Jude’s assertion that zebra and quagga mussels were causing certain fish species to starve or decline in numbers was bolstered by his 2007 assessment of fish populations in a small area of Lake Michigan’s 23,000 square 155 M E LT D O W N 155 miles. Trapped in the nets were a few perch and alewives, when there should have been many. Perch were once among the most abundant and coveted sport fish in Lake Michigan. Alewives, though an invader, fueled the lake’s billion-dollar salmon fishery. Most disturbing, however, was the presence of several round gobies that had found their way into the nets. Gobies were bottom-feeding fish that, like Dreissena mussels, were native to...