MERCURY CONCENTRATIONS CORRELATE WITH PARASITE PRESENCE IN EASTERN OYSTERS IN THE LONG ISLAND SOUND

Contaminants and parasites are ubiquitous in aquatic environments and their interactions can have detrimental effects on host physiological and ecological responses. Yet, few studies have investigated the combined influence of chemical stress and parasite infections on bivalves. We studied the relationships between mercury (Hg) and methylmercury (MeHg) and macroparasite infections of pea crabs (Zaops ostreum) on Eastern oyster (Crassotrea virginica). Between 2022-2023, pea crabs (n=95) were opportunistically collected during monthly sampling of oysters (n=674) deployed at four coastal sites in the Long Island Sound (CT, USA). Hg concentrations in oysters with pea crabs (least-squares mean ± SE: 28.8 ± 1.07 ng g-1 ww) were 13% higher than in oysters without pea crabs (25.4 ± 1.08 ng g-1 ww), with no observed difference in MeHg concentrations nor %MeHg. We did not observe significant relationships between pea crab and oyster tissue concentrations of Hg, MeHg, or %MeHg. Pea crab infection and oyster tissue Hg and MeHg concentrations were independently associated with reduced oyster condition index, suggesting an additive but not synergistic influence of these two stressors on oyster health. These results motivate additional research into the dynamics of Hg bioaccumulation in oyster-pea crab systems and their implications for the health of oysters and their consumers.

Presentation Preference: Oral

Primary Presenter: Anika Agrawal, University of Connecticut (anika.agrawal@uconn.edu)

Authors:

Anika Agrawal, University of Connecticut  (anika.agrawal@uconn.edu)

Noelie Molbert, University of Connecticut  (noelie.molbert@uconn.edu)

Robert Mason, University of Connecticut  (robert.mason@uconn.edu)

Jessica Brandt, University of Connecticut  (jess.brandt@uconn.edu)