Health of Herring Gulls (Larus argentatus) in Relation to Breeding Location in the Early 1990s. II. Cellular and Histopathological Measures

Abstract

Organosomatic indices, hematological indicators of stress, and histopathological lesions were quantified for over 150 incubating herring gulls (Larus argentatus) sampled in 11 colonies throughout the Great Lakes and reference colonies in Lake Winnipeg and the Bay of Fundy. Of 21 parameters assessed, significantly more differed between Great Lakes colonies and reference colonies than between the two reference colonies. Relative adrenal, kidney, and liver masses of gulls from some Great Lakes colonies were reduced and thyroid masses increased relative to gulls from reference colonies. Foci of cellular atypia were observed in the hepatocytes of two Great Lakes gulls. Chronic periportal hepatitis, lipogranulomas and vacuolation of hepatocytes, and chronic granulomatous interstitial nephritis were more prevalent or severe in gulls from Great Lakes colonies and were associated with contaminants. The kidneys of gulls from the three most contaminated locations were damaged and functionally compromised. Interstitial nephritis was likely the most functionally significant histopathological lesion. Portal-tract fibrosis, granulomatous hepatitis, and kidney tubule dilation/obstruction and splenic enlargement were more prevalent or severe at reference sites and were associated with blood-borne parasites. Amyloid deposits were observed in the spleen, kidneys, or liver of nearly half of the gulls. Associations between the prevalence or severity of lesions and contaminant levels in gull tissues or the trophic level of their diet suggest some lesions are toxicopathic. Associations were most frequently found with planar halogenated aromatic hydrocarbons and lead. The stress response, as measured by the heterophil/lymphocyte ratio, was attenuated in gulls from Areas of Concern and associated with decreased adrenal mass. Our findings suggest that adult Great Lakes gulls suffered from chronic exposure to chemical stressors in the early 1990s sufficient to modulate endocrine function and physiological processes and induce structural changes in tissues.

Health of Herring Gulls (Larus argentatus) in Relation to Breeding Location in the Early 1990s. III. Effects on the Bone Tissue

“…Plasma magnesium concentrations were significantly lower in Great Lakes gulls than in the freshwater reference and were significantly lower in the high-PCB colonies than the low-PCB colonies (Fox et al, 2007a). Plasma magnesium concentrations were inversely associated with nonortho-PCB and TCDD-TEQ concentrations in individual livers (Fox et al, 2007a). Plasma magnesium concentrations in loggerhead sea turtles (Caretta caretta) from North Carolina were inversely associated with ΣPCBs and TCDD-like PCB concentrations in blood (Keller et al, 2004).…”

“…Magnesium is another important constituent of bone mineral; a deficiency in Mg inhibits the osteoblastic activity (Palacios, 2006). Plasma magnesium concentrations were significantly lower in Great Lakes gulls than in the freshwater reference and were significantly lower in the high-PCB colonies than the low-PCB colonies (Fox et al, 2007a). Plasma magnesium concentrations were inversely associated with nonortho-PCB and TCDD-TEQ concentrations in individual livers (Fox et al, 2007a).…”

“…The incubating gulls were trapped on their nests using self-triggered drop traps. Gulls were weighed to the nearest 10 mg; blood was collected and various organs and tissues were collected and preserved appropriately for biochemical assays, histology, or contaminant analysis (Fox et al, 2002(Fox et al, , 2007a(Fox et al, , 2007b. Sex was determined by gonadal inspection.…”

“…These minerals are leaked from the body by damaged kidneys. Fox et al (2007a) found that chronic granulomatous interstitial nephritis was more severe in gulls from Great Lakes colonies and associated with pollutants. These findings prompted our investigation of bone composition, size, and strength in these gulls using pQCT and three-point bending which is reported here.…”

“…Tissue pollutant concentrations (Fox et al, 2002), hematological effects (Grasman et al, 2000), decreased DNA strand length (Fox et al, 2005), and biochemical, cellular, and histopathological variables of health (Fox et al, 2007a(Fox et al, , 2007b have been reported previously for these individuals. Gulls from one or more Great Lakes differed from one or both reference colonies for 17 of 19 biochemical variables, whereas the freshwater and marine reference sites differed for only 3 (Fox et al, 2007b).…”