Health of Herring Gulls (Larus argentatus) in Relation to Breeding Location in the Early 1990s. I. Biochemical Measures

Abstract

Tissues of 156 adult herring gulls (Larus argentatus) were sampled in the early 1990s from 11 colonies throughout the Laurentian Great Lakes and 2 reference colonies in Lake Winnipeg and the Bay of Fundy. Gulls from 1 or more Great Lakes differed from Lake Winnipeg or the Bay of Fundy for 17 of 19 clinical biochemical measures, whereas the freshwater and marine reference sites differed in only 3. Three differed with sex. There was little evidence to suggest that these differences reflect genotypic differences. Plasma thyroxine, albumin, calcium, magnesium, inorganic phosphorus, triglyceride, bile acids, total protein, uric acid, and urea nitrogen concentrations and aspartate aminotransferase (AST) activity were lower in gulls from one or more Great Lakes than for gulls from one or both reference sites, while those for globulins and glucose were higher. Highly carboxylated porphyrins accumulated in the livers of Great Lakes gulls and ethoxyresorufin O-deethylase (EROD) activity was induced. There was resistance to PCB/TCDD-induced EROD induction in the Lake Erie colonies. Gulls from five colonies were unable to obtain adequate food to maintain average body condition. Body condition was associated with seven biochemical measures. Colonies in designated Areas of Concern as well as those with high liver polychlorinated biphenyl (PCB) concentrations both differed for 50% of the biochemical measures. Associations between biochemical measures and delta15N-derived trophic position and/or contaminant levels in tissues suggest the effects may be toxicopathic responses. Associations were most frequently with PCBs and dioxin-like contaminants. The health of adult herring gulls varied with breeding location and "lifestyle" in the early 1990s, and Great Lakes gulls suffered from chemical and nutritional stressors that modulated physiological processes and endocrine function.

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

“…Without sufficient mineralization, bones will plastically deform under load (Turner, 2006). The measured plasma concentrations of Ca and P in the gulls show that individuals from the Great Lakes area had significantly lower concentrations compared to gulls from the freshwater reference (Fox et al, 2007b). Plasma calcium concentrations were significantly lower in the gulls from Great Lakes relative to the gulls from the freshwater reference, and were lower in gulls from the high-PCB colonies than in those from the low-PCB colonies (Fox et al, 2007b).…”

“…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). Herring gulls from some of the Great Lakes had lower plasma calcium, inorganic phosphorus, and magnesium concentrations than those from the reference colonies.…”

“…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.…”

“…Adult herring gulls were collected under federal permit using protocols and procedures approved by the National Wildlife Research Centre Animal Care Committee for the Canadian Council on Animal Care as described previously (Fox et al, 2002(Fox et al, , 2007b. Briefly, collections were timed to coincide with mid-incubation (d 7 to 21 of the 28-d incubation period.…”

“…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).…”