Organochlorine Concentrations, Eggshell Thickness, and Hatchability in Seabirds off Central California

Thickness of Common Murre (<em>Uria aalge</em>) eggshells in Atlantic Canada

“…The mean thickness of the shells of the 20 eggs collected from known established breeders on Gull island in 2013 was significantly greater than the mean thickness of eggshells measured in 2012 on Gull island (middle: 0.811, SD 0.040 mm, P < 0.001), but was not significantly greater than the mean thickness of eggshells on Machias Seal island (middle: 0.767, SD 0.078 mm, P = 0.58). California, 1968and 1970(Gress et al 1971; C, island rock and Gull island, oregon, 1979 (Henny et al 1982); D, Southeast Farallon island and Ano nuevo island, California, 1993 (Pyle et al 1999); E, Farallon islands, California, 1913 (Gress et al 1971); F, Pacific Coast, northern California to Queen Charlotte islands, British Columbia, pre-1947(Henny et al 1982G, Gull island, newfoundland and labrador, 2012;H, Machias Seal island, new Brunswick, 2006;and i, Gull island, 2013. (Uspenski 1958), eggs of Common Murres are not of uniform thickness.…”

“…A volume index was calculated as length × breadth 2 . Finally, we compared the thickness of our shell samples with previously published values (Gress et al 1971;Henny et al 1982;Pyle et al 1999;Zimmerman and Hipfner 2007) and tested differences using AnoVA and Tukey's HSD. All tests were performed in r 3.0.2 (r Development Core Team 2013), and differences were considered significant when P < 0.05.…”

Bioaccumulation of organochlorine pesticides in the liver of birds from Boraphet wetland, Thailand

“…For OCP quantification, standard solutions were used to calibrate the instrument daily. Calibration curves based on a set of concentration (5,10,20,50, 100, and 200 µg/l) were drawn. Procedural blanks, solvent blanks, and field blanks were analysed using the same procedure as the used for real samples.…”

“…Carnivorous species are at highest risk for OCP accumulation 1 . Furthermore, OCPs have been found to impact the breeding success of many bird species because they inhibit carbonic anhydrase activity and therefore lower the levels of calcium, which in turn leads to eggshell thinning and breakage [2][3][4][5] . OCPs may also affect other reproductive properties of birds, including the induction of male feminization 6 , inhibiting egglaying, decreasing clutch size 7 and hatching success 8 , and inducing deformities of the embryos 6,7 .…”

Seabird Tissue Archival and Monitoring Project:

“…Many studies have documented the declines in eggshell thickness in birds exposed to DDE (e.g., Hickey and Anderson, 1968). Pyle et al (1999) found that oxychlordane, but not DDE, was significantly correlated with eggshell thinning in common murre eggs at concentrations between 6-12 ng/g. Although concentrations of oxychlordane in murre eggs collected during this study were similar to these levels, neither oxychlordane nor 4,4'-DDE concentrations were correlated with shell thickness (R 2 = -0.11, p = 0.373 and R 2 = -0.13, p = 0.304, respectively).…”