Grass carp (Ctenopharyngodon idella) in the Trinity River, Texas

Recent confirmation of grass carp spawning in the river systems entering Galveston Bay is a serious concern to many fisheries ecologists. Researchers suspect a portion of recent losses in submersed vegetation and marsh habitat in Galveston Bay may be due to the presence of glass carp. Grass carp captured in the Trinity River were examined to determine population structure, ploidy, fecundity, and diet. Fish captured were primarily diploids and represented a broad range of cohorts, providing strong evidence that naturally spawned grass carp are being recruited to adult sizes in the Trinity River. No evidence of submersed estuarine vegetation exclusive to Trinity Bay was found in the gut contents of grass carp examined.