Isomers of Dechlorane Plus flame retardant in the eggs of herring gulls (Larus argentatus) from the Laurentian Great Lakes of North America: Temporal changes and spatial distribution

Stable nitrogen (δ15N) and carbon (δ13C) isotope values were measured in lipid-free homogenates of herring gull (Larus argentatus) eggs collected from the Laurentian Great Lakes during 1974-1995. δ15N values provided an indication of adult gull trophic position during egg formation. After adjustment of egg δ15N values for interlake differences in baseline food web δ15N signatures, significant differences in gull trophic position were found among colonies. These results were attributed to differing proportions of fish in the diets of gulls from the various colonies. Aquatic foods available to gulls had greater δ15N values than terrestrial foods. δ13C measurements provided some support for our hypothesis that terrestrial foods, particularly garbage, were more enriched in 13C than aquatic foods. As the proportion of fish in the diet decreased, the fraction consisting of terrestrial food increased, resulting in an increase in δ13C values and a decline in δ15N values. Stable isotope values for gull eggs from Lake Erie changed significantly during the study period and may have reflected a decline in fish availability.

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A QUANTITATIVE ASSESSMENT OF THYROID HISTOPATHOLOGY OF HERRING GULLS (LARUS ARGENTATUS) FROM THE GREAT LAKES AND A HYPOTHESIS ON THE CAUSAL ROLE OF ENVIRONMENTAL CONTAMINANTS

Journal of Wildlife Diseases ◽

10.7589/0090-3558-22.1.60 ◽

1986 ◽

Vol 22 (1) ◽

pp. 60-70 ◽

Cited By ~ 76

Author(s):

R. D. Moccia ◽

G. A. Fox ◽

A. Britton

Keyword(s):

Great Lakes ◽

Quantitative Assessment ◽

Environmental Contaminants ◽

Causal Role ◽

Larus Argentatus ◽

Herring Gulls

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Biogeography of the deepwater sculpin (Myoxocephalus thompsonii), a Nearctic glacial relict

Canadian Journal of Zoology ◽

10.1139/z07-125 ◽

2008 ◽

Vol 86 (2) ◽

pp. 108-115 ◽

Cited By ~ 11

Author(s):

T. A. Sheldon ◽

N. E. Mandrak ◽

N. R. Lovejoy

Keyword(s):

North America ◽

Great Lakes ◽

Current Distribution ◽

Fish Fauna ◽

Laurentian Great Lakes ◽

Glacial Lakes ◽

Deep Lakes ◽

Freshwater Fish Fauna ◽

New Localities ◽

Glacial Relict

Although the freshwater fish fauna of North America is relatively well studied, the biogeography of the deepwater sculpin ( Myoxocephalus thompsonii (Girard, 1851)) remains poorly understood. Collections of the species are limited, both because of its relatively remote distribution and because its habitat at the bottom of very deep lakes presents considerable logistic challenges for sampling. To investigate the biogeography of the deepwater sculpin, we conducted a range-wide (excluding the Laurentian Great Lakes) survey for the species between May and October 2004. Deepwater sculpin were collected using a variety of sampling gears, including a trap that was specifically designed to capture the species. We hypothesized that deepwater sculpin would be found only in areas that were formerly occupied by glacial lakes or the Champlain Sea. We reconstructed the historical boundaries of these water bodies and found that nearly all lakes where deepwater sculpin were collected, including four new localities, were within those limits. Conversely, the species was not detected in sampled lakes that were beyond these boundaries. Our results clarify the distribution and biogeography of the deepwater sculpin and strengthen the view that the current distribution of the species was mediated by dispersal through glacial lakes and the Champlain Sea.

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