April 27--More than just being the stuff of lake swimmers' nightmares, the "leech-nado" video filmed by a Shedd Aquarium researcher gives Chicagoans one more reason to spurn Green Bay.
What is a leech-nado? It's a massive, mysterious swarm of five- to seven-inch long aquatic leaches that wriggle and shimmy around, as if playing to the GoPro camera the Shedd's Solomon David stuck into a shallow body of water near the city that is home to Chicago football rivals the Packers.
David posted his video to YouTube last week, gave it the catchy title inspired by the purposely schlocky "Sharknado" film series, and watched the number of views climb. As of late morning Monday, they had passed 22,000.
David, a fish ecologist doing post-doctorate work on "habitat restoration for migratory Great Lakes fishes," including lake whitefish and northern pike, was working near Green Bay's bay, in a nondescript area where an agricultural ditch meets a wetland.
He had seen unusual things in this body of water two years running, he said in an interview: a "perch cloud," a huge aggregation of yellow perch in 2013, and "a bunch of large spawning walleye in 2014."
So he approached the pool on his most recent visit, on a Thursday in mid-April, alert for the extraordinary and, right away, he saw it.
"I've never seen an aggregation of leeches like that anywhere," he said. "And a lot of the invert people (experts in invertebrates) I spoke with hadn't seen much like this before."
His video shows a kind of underwater dance that might be described as poetic if the creatures dancing weren't, you know, leeches. Such large congregations of the parasites are rarely witnessed, David said.
David is working to identify the species of animal involved, the aquarium said in a news release, and whether they are "blood-suckers or predatory leeches that eat aquatic invertebrates."
Before he knew any of that, though, for his research he had to wade back into that water and, bare armed, place a temperature data logging device at the bottom. His flesh emerged unbroken.
