Wp. Dey et al., EPIZOOLOGY OF HEPATIC NEOPLASIA IN ATLANTIC TOMCOD (MICROGADUS TOMCOD) FROM THE HUDSON RIVER ESTUARY, Canadian journal of fisheries and aquatic sciences, 50(9), 1993, pp. 1897-1907
Atlantic tomcod (Microgadus tomcod) collected from the Hudson River es
tuary during the winter spawning season revealed neoplastic and preneo
plastic lesions in livers from 44% of the age 1 individuals and 93% of
the age 2 individuals collected. These lesions appear as a continuum
ranging from basophilic foci with little cellular alterations to hepat
ocellular carcinoma frequently involving the entire liver. Lesions wer
e more prevalent in larger individuals within the same age group, sugg
esting a relationship between growth rate and tumor expression. Atlant
ic tomcod from a relatively unpolluted estuary in Connecticut did not
reveal a comparable prevalence of hepatic lesions. Juvenile tomcod col
lected from the Hudson during the summer, only 4-5 mo prior to the win
ter spawning season had no hepatic lesions, suggesting that these lesi
ons form rapidly, coincident with gonadal maturation. Chemical analysi
s of liver tissue revealed high levels of PCBs (2.5-38.2 mg/kg) and th
e presence of several pesticides including DDT (and metabolites), chlo
rdane, and dieldrin (<0.1-3.0 mg/kg) and several heavy metals (<0.1-6.
5 mg/kg). These results suggest that chemical contamination of the low
er estuary nursery areas, coupled with high-temperature stresses of su
mmer, may contribute to the high levels of hepatic lesions observed.