Chronic stress in cunner, Tautogolabrus adspersus, exposed to municipal and industrial effluents

Chronic changes were measured in fish downstream from a pulp and paper mill located in the Humber Arm, Newfoundland, Canada. Cunner (Tautogolabrus adspersus) downstream of the mill were longer and heavier at an earlier age than reference fish. Condition factor was similar among sites. Hepatosomatic indices and ethoxyresorufin-O-deethylase activity were higher in fish near the mill. Gondal condition suggested that gametogenesis might have been delayed in these same fish. Although splenosomatic indices were greater in exposed fish, splenic hemosiderin was not significantly different from reference values. Gill and liver changes in exposed cunner were significant. Gill parasites showed no site difference; however, the prevalence and abundance of gastrointestinal acanthocephalans were significantly greater in fish from impact sites. These results suggest that effluent from this mill may be responsible for observed biological effects; however, further study is needed to determine whether gradients in nutrient loading and untreated sewage discharge may also contribute to fish health in the Humber Arm.