Meeting Abstract

62.9  Wednesday, Jan. 6  Impact of an Elevated Sea Level Anomaly on Fish Recruitment to a Georgia Estuary FRANCIS, JR., A.W.; Armstrong Atlantic State Univ., Savannah, GA austin.francis@armstrong.edu

The occurrence and abundance of fish species in shallow coastal waters and estuaries is generally determined by atmospheric and oceanographic processes coupled with fish behavior. It was the goal of this investigation to identify temporal and spatial patterns of fish recruitment in a Georgia estuarine nursery area. Larval and juvenile fishes were collected using an ichthyoplankton net deployed during night flood tides when larvae were most likely to be suspended in the water column. All sampling was conducted at the Moon River, a tidal stream of Skidaway Island that empties into Wassaw Sound. Samples were collected once a week from April 9, 2009 until July 28, 2009 and fixed in 10% formalin. Environmental conditions were assessed by recording air and water temperature, salinity, and current speed. Additional meteorological data, including fraction of moon illuminated, atmospheric pressure, wind speed, cloud cover, and precipitation, were obtained from U.S. Naval Observatory and National Oceanographic and Atmospheric Administration databases. In the laboratory, ichthyoplankton was sorted and identified to lowest possible taxon. Over a period of 16 weeks, a total of 13,994 fish were collected, representing 25 species from 14 families. Several species had not been previously described as occurring along Georgia’s shallow coastal waters or estuaries. The dominant species in most samples was the bay anchovy, Anchoa mitchilli, representing 94.2% of the total catch. The greatest numbers of fishes were collected during the new moon. In late June, an elevated sea level anomaly contributed to a recruitment event more than 30 times the recruitment observed before or after the anomaly. Stochastic physical processes that elevate coastal sea level appear to enhance recruitment for at least some fishes.