A Comparison of Fish Kills in the Pamlico River and the Neuse River in Coastal North Carolina (A Symptom) and Abiotic Factors (The Root Causes)

For many decades the State of North Carolina (NC) witnessed fish kills in its coastal waters, particularly its inshore coastal estuarine and riverine waters. This study looks at fish kill data collected from two adjacent coastal rivers, the Neuse River and the Pamlico River, which both experienced fish kills over an 11 year period, and looks at possible naturally occurring abiotic environmental factors which may have contributed to or been responsible for the documented numbers of fish kill events and the sizes of those individual and collective events. In our study, naturally occurring abiotic environmental factors, including excessive precipitation or the lack thereof, and seasonal atmospheric wind fields, and subsequent estuarine circulations, were found to be responsible for creating strongly vertically salt stratified conditions in both river-estuaries, lowering dissolved oxygen levels in the bottom layers in the two separate rivers. We also present the possibility that excessive nutrient loading of both rivers may be responsible for lowering oxygen levels. These factors may have resulted in the fish kills.