Education Level

Undergraduate

Faculty Advisor(s)

Professor David Taylor

Academic Department(s)

Marine and Natural Sciences

Comments

This research was presented at the 2024 Rhode Island Summer Undergraduate Research Symposium, held on Friday, July 26, at the University of Rhode Island and supported by independent research with Dr. David Taylor.

Symposium Date

2024

Abstract

Mercury is a widespread environmental contaminant that poses a threat to human and wildlife health. Mercury concentrations ([Hg]) may be elevated in fish tissues due to individual bioaccumulation and biomagnification in the food web. This study examined Hg bioaccumulation rates in striped bass (SB) and largemouth bass (LMB): top-level predatory fishes in marine and freshwater environments. SB, LMB, and their prey were collected in Rhode Island waters from 2006 to 2023 using rod & reel, electrofishing, and trawling methods. Age (yr) was determined for each fish based on measurements of total lengths (TL; cm) in the laboratory (LMB: 15-57 cm, 1-18 yr, n = 412; SB: 26-105 cm, 2-12 yr, n = 231). Muscle tissue excised from SB and LMB, as well as prey whole bodies, were analyzed for total [Hg] (ppm wet weight) using automated atomic-absorption spectroscopy. Total [Hg] of SB were significantly lower than LMB despite no difference in the species’ trophic position, as calculated from stable nitrogen isotopes, and SB being older and larger in body size. Prey of LMB (juvenile conspecifics, sunfishes, and crayfish) had higher [Hg] compared to SB prey (forage fish, squid, and crabs), which may explain interspecific differences in Hg contamination. Growth dilution and variations in feeding and excretion rates may also contribute to higher [Hg] in LMB relative to SB. Lastly, total [Hg] of legally harvestable LMB and SB routinely exceeded the US EPA threshold level; thus, frequent consumption of either species may adversely affect human health.

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