What does the research show as far as sea lamprey in the river now, both above and below the 6th Street Dam?  By

What does the research show as far as sea lamprey in the river now, both above and below the 6th Street Dam?

Sea lampreys enter the Grand River from Lake Michigan and inhabit the river downstream of the 6th Street Dam.  That stretch of the river contains poor sea lamprey habitat and the stretch is not productive enough to warrant treatments in the Grand itself.  Crockery and Norris creeks, located downstream of the Sixth Street dam, are treated regularly. The upper Grand River and its tributaries have been regularly surveyed for sea lampreys since 1962.  A total of 44 tributaries upstream of the Sixth Street dam have been surveyed.  Two sea lamprey escapement events have been noted upstream of the Sixth Street dam.  Larval sea lampreys were collected from Lowell Creek in 1962 and the stream was treated with TFM (3-trifluoromethyl-4′-nitrophenol) in 1965.  Larval sea lampreys were collected from the Rogue River during 2008, resulting in a treatment in 2009.  The source(s) of escapement for each event is unknown. Harmless, native lampreys are known to occupy reaches of the watershed upstream of the Sixth Street dam.