Low Levels of Bioaccumulated Mercury in Lobster (Homarus Americanus) From the Gulf of Maine Are Elevated During the Early Fishing Season

Overview

Mercury (Hg) pollutes marine ecosystems and concentrates in benthic species. This ecological case study investigated the temporal accumulation of Hg in American lobster ( Homarus americanus) as a bottom -dwelling species in coastal waters (Casco Bay, Maine, USA). We analyzed total Hg levels in legal-sized lobsters (carapace length: 8.255 - 12.5 cm; n=34) collected during the early (May -July 1st) or late (July 15th -October) recreational harves t seasons. Morphometric data show that individual body sizes correlate with individual body weights (R2=0.76; p<0.001) and average body sizes were similar in early and late seasons. The average chelipod (crushing claw) size was ~7% larger in male lobsters (p<0.02) reflecting sexual dimorphism. Hg levels in select tissues from boiled lobsters were analyzed by atomic absorption spectroscopy. Hg in ambient water was undetectable indicating that Hg in tissues reflects bioaccumulation. Hg content correlated with the sizes (cm) and weights (g) of carapace (body), chelipod and hepatopancreas (tomalley) in male and female lobsters. The total Hg levels in most tissues examined are safe and acceptable for human consumption (<0.2 ppm). Compared to late season lobsters, early season lobsters have significantly more Hg in tail muscle (~55% increase; 0.130 ppm vs 0.084 ppm; p<0.05) and tomalley tissue (~29% increase; 0.099 ppm vs 0.077 ppm; p<0.05). These findings indicate that seasonal factors modulate Hg content in this coastal habitat (e.g., spring river run-off, lobster migration). The observed seasonal fluctuations in the Hg levels of lobsters may inform other studies and mitigation strategies for pollution patterns in coastal marine ecosystems.

Competition history

• JSHS 2025 Category not listed

Resources

• National JSHS abstract book ↗

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