Status of shortnose sturgeon in the Neuse River, North Carolina

Shortnose sturgeon Acipenser brevirostrum historically occurred in most major Atlantic Coast rivers from Saint Johns River, New Brunswick, Canada to St. John's River, Florida. However, there are few records of shortnose sturgeon occurrences within North Carolina and none from the Neuse River. We conducted a 2-year intensive gill-net survey, following the National Marine Fisheries Service sampling protocol, and a reward program in order to determine their population status within the Neuse River. No shortnose sturgeon were observed, although 10 juvenile Atlantic sturgeon (506-992 mm fork length) were encountered. Habitat surveys of the lower Neuse River, where shortnose sturgeon would be expected to occur during summer, showed that bottom waters were severely hypoxic during June-September of 2001-2002. A juvenile Atlantic sturgeon tagged with an ultrasonic transmitter moved upstream of the unsuitable summer habitat and remained in a restricted area until late fall, when water quality improved due to increased flows and lower temperatures. We developed logistic regression models of watershed and river characteristics based on 36 Atlantic Coast rivers with a known presence or absence of shortnose sturgeon. Model predictions suggest that the Neuse River should contain a population of shortnose sturgeon based on the amount of physical habitat. We hypothesize that shortnose sturgeon have been extirpated from the Neuse River due to a lack of suitable summer habitat. Population recovery may be impossible until habitat quality can be improved.