PM15 Biomarkers
Exhibit Hall
8:00 AM - Monday
(PM246) Histopathology of common carp (Cyprinus carpio) collected from the Lake Mead National Recreational Area.
Hinck, J1, Papoulias, D1, Tillitt, D1, 1 USGS-CERC, Columbia, Missouri, USA
ABSTRACT- Male and female carp (Cyprinus carpio) were collected in the fall of 2003 from Pearce Ferry and Willow Beach, located within the Lake Mead National Recreational Area, as part of the Biomonitoring of Environmental Status and Trends (BEST) Large River Program - Colorado River Basin Project. The BEST program is a national monitoring effort that measures whole-body concentrations of selected contaminants and evaluates biomarker responses in fish from large river basins. The incidence and severity of macrophage aggregates, oocyte atresia, and the overall health of carp from Pearce Ferry and Willow Beach were compared to carp from other sampling locations within the Colorado Basin. Fish health assessments were performed in the field to identify external and internal gross anomalies. Samples were also taken for histopathological examinations of various tissues including spleen, gonads, kidneys, liver, and gills. Macrophage aggregate analysis of spleen and gonad tissues examined cellular-level immune response. Carp from Pearce Ferry and Willow Beach differed in gross morphology when compared to carp collected from other locations in the Colorado basin. Specifically, many carp from these two sites had thinned body walls, fluid-filled abdomens, and inflamed anal pore; characteristics consistent with infectious abdominal dropsy of cyprinids. Histological examination of the gonads revealed one intersex carp. Carp from Pearce Ferry and Willow Beach had significantly greater macrophage aggregates (size and percent tissue occupied) than carp collected from other stations in the lower Colorado River. Multiple female carp from Pearce Ferry and Willow Beach had oocyte atresia exceeding 21%, a percentage that was rare in female carp from other sites in the Colorado Basin. The cause(s) of the observed poorer health of carp from Pearce Ferry and Willow Beach are unknown. However, our information suggests the need for further study to better understand the factors contributing to unhealthy fish in this recreational area.
Key words: Colorado River, fish health , ovotestis, benthivores