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Neuse River & Pamlico Sound


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Short-term hurricane impacts

The fall of 1999 was a very unusual fall with 3 hurricanes, Dennis, Floyd, and Irene passing through North Carolina during a 6 week period between September 4th and October 17th. These three sequential hurricanes inundated eastern North Carolina with up to 1 m of rainfall, causing 500-year flooding in the Neuse River watershed. Portions of the Neuse River Basin received about 75 cm of rain during 2 months. More than one-half of the annual rainfall fell during September (North Carolina Climatological Office, Raleigh NC). High rates of freshwater inflow into the Neuse and Pamlico turned a brackish water estuary with typical fall salinities between 12 - 20 ppt to a completely fresh estuary down to the sound where surface salinities were < 5 ppt

This strong salinity front was captured in a SEAWHIF photograph:

Associated with this large perturbation were dramatic shifts in the fish community. Associated with the pulse of freshwater was several freshwater species, longnose gar, catfish, and yellow perch

Yellow Perch Catfish Longnose gar

Most of the larger juvenile fish left the estuary resulting in decreases in both catch and sizes for many fish species (e.g. spot, croaker, blue crab, silver perch, anchovy, menhaden, etc.). Total catch per unit effort usually stays the same or increases through October, but after Hurricane Floyd, catch per unit effort declined by half in the Neuse River estuary

An economically important short-term impact was that after Hurricane Floyd, not only were catches down, but the sizes of blue crabs had decreased to where there were very few legal size crabs remaining in the estuary and sound

Although the freshwater was throughout the entire water column upstream, as the estuary opened up into Pamlico Sound it formed a strong stratification with subsequent hypoxia in the bottom waters after Hurricane Floyd. This stratification was broken down by the high winds from Hurricane Irene. This hypoxic area had fish with higher rates of lesions, sores, sloughing skin, and systematic bacterial infections (Ed. Noga, NCSU, pers.comm.)

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