Factors influencing mercury accumulation in three species of forage fish from Caddo Lake, Texas, USA

Most studies that have examined mercury (Hg) contamination of fish have focused on game species feeding near the top of the food web, while studies that examine forage fish that feed near the base of the food web are rare. We conducted a survey of Hg contamination in three species of forage fish, brook silverside (Labidesthes sicculus), threadfin shad (Dorosoma petenense) and gizzard shad (Dorosoma cepedianum), from Caddo Lake, Texas, USA and found species-specific di erences in Hg concentrations. We examined total length, age, trophic position (determined using 15N), and growth rate of forage fish as factors that could have influenced within- and between-species di erences in Hg concentration. Total length and age were the best predictors of within-species di erences in Hg concentration. Between-species di erences in Hg concentrations were most strongly influenced by trophic position.