Mitochondrial DNA phylogeography of least cisco Coregonus sardinella in Alaska.

This study presents the first detailed analysis of the mitochondrial DNA diversity of least cisco Coregonus sardinella in Alaska using a 678 bp segment of the control region (D-loop) of the mitochondrial genome. Findings suggest that the history of C. sardinella in Alaska differs from that of other species of Coregonus present in the state and surrounding regions. The examined populations of C. sardinella are genetically diverse across Alaska. Sixty-eight distinct mitochondrial haplotypes were identified among 305 individuals sampled from nine locations. The haplotype minimum spanning network and phylogeny showed a modest level of geographic segregation among haplotypes, suggesting high levels of on-going or recent connectivity among distant populations. Observed ΦST values and the results of homogeneity and AMOVAs indicate incipient genetic differentiation between aggregations in three broad regional groups. Sites north of the Brooks Range formed one group, sites in the Yukon and Selawik Rivers formed a second group and sites south of the Yukon drainage formed the third group. Overall, the sequence data showed that a large proportion of mtDNA genetic variation in C. sardinella is shared across Alaska, but this variation is not homogeneously distributed across all regions and for all haplotype groups.

Metals in feathers of black-crowned night-heron (Nycticorax nycticorax) chicks from the New York Harbor Estuary.

In heavily urbanized landscapes such as the New York Harbor Estuary, the local environment is subject to a variety of contamination sources. Environmental contaminants such as heavy metals and metalloids pose a risk to wildlife inhabiting the harbor. Metal concentrations in feathers indicate exposure and provide insight into the potential adverse effects on birds. In 2004 and 2005 down feathers were collected from 147 black-crowned night heron (Nycticorax nycticorax) chicks living on four island colonies in the New York Harbor Estuary, USA: Goose Island, Hoffman Island, North Brother Island, and Canarsie Pol. We examined geographical and interannual differences in concentrations of the metalloid arsenic (As) and the heavy metals cadmium (Cd), chromium (Cr), lead (Pb), and mercury (Hg). Significant differences in metal concentrations were a function of location, with North Brother Island having the highest As concentrations and Goose Island having the highest Cr and Pb concentrations in feathers collected in 2004. In 2005, feather samples indicated Hoffman Island had the highest Cr concentrations and North Brother Island had the highest Pb and Hg concentrations. Concentrations of As, Cd, and Hg decreased significantly from 2004 to 2005 on North Brother Island, Hg on Hoffman Island decreased from 2004 to 2005, while Cr on Hoffman Island increased from 2004 to 2005. Cd and Pb concentrations were higher and As and Cr concentrations were generally lower than concentrations reported in previous studies. Further investigation is necessary on the declining population of herons in the New York Harbor Estuary to determine specifically if birds are experiencing adverse effects from metal contaminants, or if organic contaminants, such as organic Hg or polychlorinated biphenyls (PCBs), are playing a role in this population's decline.