MacAvoy, S. E. University of Virginia, sem7e@virginia.edu
Macko, S. E. University of Virginia, sam8f@virginia.edu
McIninch, S. Virginia Commonwealth University, spmcinin@atlas.vcu.edu
Garman, G. C. Virginia Commonwealth University, ggarman@atlas.vcu.edu

 
QUANTIFYING THE CONTRIBUTION OF ANADROMOUS CLUPEID FISH TO THE DIET OF AN INTRODUCED, APEX PREDATOR (BLUE CATFISH, ICTALURUS FURCATUS) IN TIDAL FRESHWATER USING STABLE ISOTOPES
 
The tidal freshwater systems in Virginia are oligotrophic, have few piscivores and support substantial populations of anadromous clupeid fish (herring, shad and alewife) during the spring spawning run. The anadromous clupeid fish are commercially valuable and may bring nutrients to the tidal freshwater. Blue catfish (Ictalurus furcatus), an introduced piscivorous fish, may preferentially consume the anadromous clupeids during the spring. Because of differences in del34S and del13C between the freshwater and marine environments, these isotopes are powerful tools for evaluating the contribution of marine derived nutrients to freshwater systems. Anadromous clupeids captured in the tidal freshwater streams of Virginia are enriched in del34S (17.1 to 20.4) and del13C (-20.8 to -17.1) compared to resident freshwater species (3.5 to 8.3 and -28.6 to -22.3). I. furcatus, (*38 cm TL) captured in tidal freshwater in the spring, are enriched in del34S (10.4 ± 2.5, N=8) and del13C (-20.4 ± 3.2, N=5) compared to other freshwater species. This shows a substantial contribution of marine biomass to the diet of I. furcatus. Anadromous clupeids are the dominant source of marine derived sulfur and carbon in tidal freshwater, therefore, the enriched isotopic values of I. furcatus reflect anadromous clupeid consumption.
 
Day: Wednesday, Feb. 3
Time: 10:45 - 11:00am
Location: Eldorado Hotel
 
Code: SS32WE1045E