Cliff's Notes

From May, 1997 (Update #30)

It was hectic day at the office. Everything that came up was interesting and needed quick attention. Visitors had come a long way to work on a project. The phone kept ringing. Then there was a caller with a friendly voice telling me I was wrong. "Hi Cliff, this is Joe Leach. In your last newsletter you implied that zebra mussels never caused buoys to sink. Well, they did. I can fax you a letter to prove it." Oops. I knew from experience that Joe Leach was an accurate supplier of information. My office visitors must have noticed my telephone voice change to a conciliatory tone of, "Gee, please send me that fax, Joe, I was just trying to verify these apocryphal stories. Thanks. . ." So here's the scoop. In 1990 Louis Goulet, vice president of Pembina Exploration Limited, in Port Colbourne, Ontario, wrote a letter to the Ontario Ministry of Natural Resources describing problems that zebra mussels were causing for their gas well markers. The letter stated that "The added weight of the zebra mussels attaching themselves to the (gas) well markers eventually forces the marker to lake bottom. This also creates another problem for the fishermen and Great Lakes shipping industry in identifying the location of our wells and pipelines." In order to learn what's happening with gas markers today, I called Pembina. Goulet is no longer with the company, so I spoke with Bruce Petrochuk, diving superintendent. He said zebra mussel colonization is currently nowhere near as bad as in "years two or three" of the infestation. But yes, in the early years zebra mussels had sunk markers used to identify nearly 750 Lake Erie underwater gas wellheads, plus another 150 pipeline junctions. Prior to the zebra mussel invasion, Pembina used 2 foot by 18 foot wooden poles as markers, of which about five feet stuck above the surface as a warning to boaters. After the weight of zebra mussels caused some of these markers to sink completely below the surface, Pembina tried different markers with greater buoyancy. Some five-inch PVC pipe, floatation foam on the inside, a couple of caps, and that zebra mussel problem was licked. Petrochuk added that overall, zebra mussels have increased Pembina's operating costs by requiring periodic cleaning of underwater gas wellheads and junctions. He said that with dive operations costing around $4,500 per day, anything that adds 10% more time to a job is "real money." However, he also noted that increased underwater visibility caused by the mussels has helped speed up some tasks, thereby compensating somewhat for extra dive time spent cleaning mussels off equipment. The 1990 Pembina letter also contains this intriguing observation: "The presence of this tiny black and white mollusk, first observed four years ago (emphasis added) on our wellheads and well markers. . ." If accurate, this would indicate a 1986 sighting from Lake Erie. Oh no! Should I publicly question the accuracy of Pembina's observation? If not, it's time to re- evaluate another zebra mussel legend, the one that starts every publication and presentation: "First discovered in Lake St. Clair in June 1988. . ." I've suspected this was questionable ever since the second issue of this newsletter reported an Illinois museum had zebra mussel shells collected from a southern Lake Michigan tributary in May 1988. Well, I can't help but be curious about the lore of zebra mussels. Maybe I'll get another phone call to help out.

ID: 199705-14.

The Zebra Mussel Update was a 4- to 8-page quarterly national newsletter published by the University of Wisconsin Sea Grant Institute from May 1990 through May 1997. The ZMU documented the spread of the zebra mussel -- an exotic nuisance mussel -- through North America's freshwater environments, especially the Great Lakes, and on efforts to control it.