The History of Iowa's Nonnative Aquatic Introductions, 1874 - 2014

The state of Iowa is bordered by the Missouri River to the west and the Mississippi River to the east. These hydrologic connections make Iowa’s waterbodies extremely vulnerable to aquatic invasions. Throughout the recorded history of Iowa’s fisheries there have been a wide range of aquatic introductions from the introduction of Common Carp (Cyprinus carpio) in 1880 to the present day issues with Zebra Mussels (Dreissena polymorpha) and Silver Carp (Hypophthalmichthys molitrix). Upon investigating this historical information, two general periods of introductions can be depicted. The late 1800’s through the early 1960’s witnessed many purposeful introductions in an attempt to increase the sport fisheries of the state and the period from the 1980’s to present day  has experienced multiple accidental invasions such as the introduction of Zebra Mussels or Eurasian Water Milfoil (Myriophyllum spicatum). For every invasion during these periods, the approximate invasion date and method of introduction is given for each species. Overall, these data suggest that both accidental and intentional introduction to the state both have similar ecological impacts to Iowa’s waters. To this end, determining the cause of past introductions and increasing outreach relating to invasive species can prevent the occurrence of future issues.