TShad are plankton feeders and are pelagic (open water ) feeders in schools. If a population survives to next spring you may have established an on going population ( absent real cold winter water temps.( 42 ) or the LMB eating them all) Here are 2 links with info.

http://srac.tamu.edu/tmppdfs/11830457-140fs.pdf

http://www.fishbase.org/Summary/SpeciesSummary.php?id=1606