The Mississippi River’s spring pulse is upon us, bringing both good and bad news. Flooding has been tempered by slow snow melt in the north. Flooding has benefits in that it removes trash that litters the shoreline and either pushes it a little higher on the shore or sends it to our neighbors down south. Extended periods of high water contribute to increased sedimentation and filling in of backwaters, which is a chronic problem in our area.
The spring high water provides perfect conditions for Asian carp, bigheads and silvers, to migrate upriver. These Asian invaders escaped from Arkansas fish farms in the 1970s and began their trek north, south, east and west. They compete directly with our native fish in their diet of phytoplankton and have taken over much of the Illinois River fishery. There have been infrequent reports of Asian carp this far north on the Mississippi River. However, in April, a 36- inch, 21-pound silver carp was caught in Dubuque and in a nearby area Asian carp eggs and embryos were discovered. A 73-pound bighead was caught in Sabula Lake in June 2012. Monster bigheads can weigh 90 pounds and measure 60 inches long.
Silver carp are the notorious flying fish that leap from the water in large numbers when a passing boat’s motor excites them. Accidents with humans are common when boaters, skiers, and tubers are hit by the flying fish. Two underwater electric barriers span the Sanitary Ship Canal near Chicago and emit shock waves to keep these invasive carp from entering Lake Michigan and impacting the multi-million dollar fishing industry.
The great white trawlers, American white pelicans, have returned in large numbers and grace the shorelines and skylines with their synchronized swimming and aerial acrobatics. They arrived on the trailing edge of ice, taking advantage of cold water temperatures to scoop up slow moving fish. The pelicans are nesting on several island sandy beaches located north of Clinton in Pool 13. They are joined by their colonial nesting buddies, great blue herons, great egrets and double-crested cormorants. These islands are the only known white pelican nesting colonies on the Upper Mississippi River.