With concern rising that invasive Asian carp will make their way up the Mississippi River into some of Minnesota’s prime fishing waters, it appears increasingly likely that Congress will authorize the closure of a key navigational lock in Minneapolis, effectively ending the city’s days as a river port.

On Sept. 15, crews from scads of state and federal agencies launched a small fleet of research boats at Hidden Falls Regional Park in St. Paul, looking for an answer to a suddenly pressing question: Have two species of the dreaded Asian carp finally worked their way up the Mississippi River to the Twin Cities?