Meeting Abstract

36.3  Sunday, Jan. 5 08:30  Hepatic Melanomacrophage Aggregates and Metal Bioaccumulation in Spotted Gar (Lepisosteus oculatus) FRENCH, J.D.*; YOUNG, J.E.; CHUMCHALL, M.M.; BRINKMAN, E.L.; MOORE, B.C.; Louisiana Tech University; Louisiana Tech University; Texas Christian University; Arkansas Game and Fish Commission; Louisiana Tech University jdf040@latech.edu

Toxic metal contamination of aquatic environments can pose serious health threats to fish, especially those in higher trophic levels due to tissue buildup through biomagnification. Elevated mercury concentrations can jeopardize overall fish health in various ways including liver damage resulting in robust immune response. Hepatic mercury accumulation has been demonstrated to increase the formation of melanomacrophages in spotted gar, putatively as a consequence of chronic mercury-mediated tissue damage and resulting inflammation. Additionally, melanomacrophage aggregates scavenge iron after tissue damage. We investigated the relationship between hepatic mercury and iron concentrations and the frequency of liver melanomacrophages in spotted gar from two southern Arkansas lakes (Calion Lake and Felsenthal National Wildlife Refuge) with varying levels of mercury contamination. We quantified the number, size, and frequency of melanomacrophages and the concentrations of total mercury and iron in the liver tissues. Lower liver mercury concentrations were found in the fish from the control site, Calion Lake, compared to those from Felsenthal NWR. Both collections of fish from Felsenthal NWR also exhibited increased hepatic melanomacrophage aggregates with higher mercury concentrations. These associations, along with variations in iron concentrations, will be discussed in light of possible detriments to spotted gar health and potentially other fish in similar environmental conditions.