Publications

To facilitate decisions to classify species according to risk of extinction, we used Bayesian methods to analyze trend data for the Spectacled Eider, an arctic sea duck. Trend data from three independent surveys of the Yukon-Kuskokwim Delta were analyzed individually and in combination to yield posterior distributions for population growth rates. We used classification criteria developed...

Several years ago, Science published an important essay (Ludwig et al. 1993) on the need to confront the scientific uncertainty associated with managing natural resources. The essay did not discuss instream flow standards explicitly, but its arguments apply. At an April 1995 workshop in Davis, California, all 12 participants agreed that currently no scientifically defensible method...

No abstract available.

Seaducks (Tribe Mergini) are a diverse group of birds. In North America, many species nest in boreal or arctic habitats in Canada and Alaska and winter in ice-free coastal, marine, and freshwater habitats. Data from long- term surveys, population studies, and local knowledge suggest that some populations and species of seaducks have declined over the past decades. In most cases, the...

The activity and feeding behavior of ovigerous Dungeness crabs, Cancer magister, were examined as part of a long-term study. Part of this study surveyed Bartlett Cove in Glacier Bay, Alaska, during the spring of 1994 where 50 commercial pots were soaked for 24 hours. Catch per unit effort (CPUE), dispersion, and stomach samples of male, nonovigerous female, and ovigerous female crabs...

Patterns of micro- to mesoscale distribution of Dungeness crabs (Cancer magister) in nearshore habitats at five locations in and near Glacier Bay National Park were revealed using subtidal transects. Sampling was conducted in April and September 1992 and 1993 and April 1994. Divers censused crabs by sex and reproductive status (ovigerous/nonovigerous females) along belt transects (2 m x...

Surface and ground water in Nebraska may contain contaminants resulting from human activities. For purposes of this publication, a contaminant is any element or compound whose presence may affect the water's suitability for certain uses. For example, herbicide concentrations may exceeed the U.S. Environmental Protection Agency's (USEPA) Health Advisory Levels (HAL) for drinking water or...

Dispersal is of central importance to population biology, behavioral ecology and conservation. However, because field studies are based on finite study areas, nearly all dispersal distributions for vertebrates currently available are biased, often highly so. The inadequacy of dispersal data obtained directly by traditional methods using population studies of marked individuals is...

Previous studies have demonstrated several reproductive-behavior patterns in male salmon, including competitive and sneaking tactics, the formation of hierarchies, and non-hierarchical aggregations around ripe females. Through behavioral observations at varying spatial and temporal scales, we examined the hypothesis that operational sex ratio (OSR) determines male sockeye salmon...

We used restriction-enzyme analysis of polymerase-chain reaction-amplified, mitochondrial DNA (mtDNA) to assess genetic differentiation of subspecies and populations of sea otters, Enhydra lutris, throughout the range of the species. There were several haplotypes of mtDNA in each subspecies and geographically separate populations. MtDNA sequence divergence of haplotypes of sea otters was...

Short-term effects of the 1989 TV Exxon Valdez oil spill on seabirds were dramatic and well documented. Seabird populations at sea in the spill zone were immediately depressed, and more than 30,000 dead, oiled seabirds were recovered from beaches within months of the spill. It is estimated that 250,000 seabirds were killed by oil, of which 74% were murres. Based on comparisons of...

We measured forage intake, digestibility, and retention time for 11 free-ranging, human-imprinted lesser snow geese (Chen caerulescens caerulescens) as they consumed underground stembases of tall cotton-grass (Eriophorum angustifolium) on an arctic staging area in northeastern Alaska. Geese fed in small patches (x̄=21.5 m2) of forage that made up ≤3% of the study area and consisted of...