The discovery of a rare subspecies of fish in the Lake of the Isles has created yet another challenge for the planners and engineers working on the long-planned extension of the Green Line light rail project into the southwest suburbs. Called the Minnesota lake shark, or selachimorpha calhounus, and once thought to be be extinct, the appearance of of the fish in the murky spring waters of the Chain of Lakes comes with unfortunate effects for transit planners. As one of the only mid-continental lake sharks in the country, the subspecies means new rules regulating environmental impacts.
“This is certainly the sharpest challenge we have faced on an already complicated project,” announced Metro Transit planner Rachel Owlglass at a press conference on the shores of Bde Mka Ska yesterday afternoon. “Nobody expected a shark.”
The Minnesota lake shark, selachimorpha calhounus, pretending to ignore its prey.
The rare Minnesota lake shark is notorious amongst inland marine biologists for being finicky about its aquatic environment. Unlike most sharks, which simply attack without mercy, the Minnesota lake shark relies on passive aggressive hunting tactics shark that render it sensitive to subterranean tremors.
“It’s a unique fish,” said prairie ichthyologist Horst Achtfaden of the Saint Paul-based Mid-Continent Oceanographic Institute. “It’s the only predatory shark that simply makes its prey feel bad about itself until succumbing to a lethal depression, at which point the shark will eagerly devour it. You don’t see anything like that in coastal communities.”
Because of the Minnesota lake shark’s feeding habits — it feeds primarily on the locally-specific grey duck population — mean that the proposed transit connection will not be able to tunnel under the lake channel as previously planned. Projected light rail trains would severely affect the passive-aggressive vibrations on which the sensitive fish relies.
Yet according to the fish scientists, Minnesota lake sharks are also extremely sensitive to seasonal affective disorder. They must maintain sight lines of the sky at all times, and that challenge means that a bridge for the planned light rail line is also not possible at the choke point. For the first time on a project plagued by unexpected challenges, the lake shark left light rail planners at an impasse.
That all changed when, earlier this week, an unexpected solution presented itself.
Some of the new Metro Transit LRT cars, preparing for shark-jump pre-testing.
“At first we were stumped by this,” admitted Judith Prietht, a planner working on the project. “At our recent technical committee meeting, we sat in the conference room for a few hours murmuring gibberish, until one of our engineering team hit upon an idea, something they remembered from an old episode of Happy Days.”
The proposed plan, which still needs local approval, is for the train to launch itself off a ramp on one side of the shark habitat and to land neatly on the other side of the canal using an innovative “catch basin.”
“The shark-jump will come with a groundbreaking design featuring inertial dampeners that will allow each light rail passenger to continue comfortably over the shark habitat,” explained Zepho Bark, an engineer for the engineering firm SITCOM, which has been the lead consultant on the transit project.
“Thank goodness we chose light rail instead of heavy rail as our locally preferred option,” Bark added. “That weighty decision is what made this technical solution possible.”
The light-rail shark-jump will be the first of its kind in the Twin Cities metro area, and sets precedents for future projects of a similar complexity, like the proposed but long-stalled Eagan Eagle Enjoyment Elevated, the Richfield Raccoon-Retention Ring Road, and the Saint Paul Fungus Funicular.