P1.187 Wednesday, Jan. 4 Catch and Compare: Ichthoplankton Sampling Methods in a Georgia Estuary KNIGHT, M.S.*; FRANCIS, JR., A.W.; Armstrong Atlantic State Univ., Savannah, GA firstname.lastname@example.org
This study examined the temporal distribution and abundance of ichthyoplankton occurring in the Moon River, a salt marsh estuary near Savannah, Georgia using two different nets over a three month period. The purpose of this study was to determine the effect of net design on ichthoplankton sampling by comparing juvenile fish collected by two different nets. Beginning in July 2011, weekly sampling was performed on a night flood tide. The two nets were deployed three separate times for 30 minutes each. Both ichthyoplankton nets had a diameter of 1 m, a 3:1 shape, and 1 mm in mesh. One net was a traditional bridle-based setup with an attached cod end jar. The second net was bridle-less with a dorsal float and ventral weight to orient the net and a bucket clasped to the end. The float and weight combination allowed the net to be lower in the water column than the bridled net. The bucket had several openings on one side covered by 1 mm mesh allowing water to pass through the end of the net. Additional abiotic factors were measured including weather and presence or absence of the moon, salinity, pH, dissolved oxygen, water depth, water temperature, water flow, and air temperature. The samples were preserved in the field with 10% formalin. In the lab, samples were sorted, identified to the lowest taxon, and transferred to 70% ethyl alcohol. A comparison of each net’s numbers of juvenile fish demonstrated that the bridle-less net collected greater numbers of each species than the bridled net. The bridle-less net also collected more species than the bridled net. The most common juvenile fishes were Anchoa mitchilli, Gobiosoma bosc, Gobiosoma robustum, and Microgobius thalassinus. M. thalassinus was one species only collected in the bridle-less net.