Publications

We estimated age at sexual maturity and age-specific reproductive rates by examining carcasses and reproductive tracts from 177 female sea otters (Enhydra lutris). Carcasses were recovered from south-central Alaska, Primarily from western Prince William Sound, as a result of the T/V Exxon Valdez oil spill in 1989. We found 65% of our sample to be sexually mature. Sexual maturity was...

Results from two experiments are presented that contrast differences in life-history traits and population dynamics between two species of live bearing fishes (Gambusia affinis and G. holbrooki) that hybridize across portions of the southeastern United States. Progeny from parental holbrooki and holbrooki-affinis F1 crosses exhibited larger lengths at birth, at 15 days, and matured...

Natural populations of many species are increasingly impacted by human activities. Perturbations are particularly pronunced for large ungulates due in part to sport and commercial harvest, to reductions and fragmentation of native habitat, and as the result of reintroductions. These perturbations affect population size, sex and age composition, and population breeding structure, and as a

Several recently published papers discussed the importance of systematics (the study of evolutionary and genetic relationships among organisms) and taxonomy (the naming and classification of organisms) for managing wildlife (Ryder 1986, Avise 1989, Amato 1991, O'Brien and Mayr 1991, Dowling et al. 1992), Often, classification below the species level is needed; for example, the Endangered...

Laysan albatrosses (Diomedea immutabilis) are among the most prominent bird species which interact with commercial fisheries in the North Pacific. They are attracted to fishing nets and vessels and feed extensively on animals caught in nets, waste fish, offal, and refuse discarded from vessels. Approximately 17,500 individuals were killed in the five major high seas driftnet fisheries in...

Biomarkers may be used to determine chemical exposure and effects in several important ways. These include (1) evaluation of new agricultural or industrial chemicals for effects, (2) screening of municipal or industrial effluents, (3) determining the geographic distribution of chemical effects in the environment and their changes over time, (4) determining the identity and source of...

The kelp forest fishes of San Nicolas Island, California were studied from 1981-1986 to examine the causes of among-site and among-year variation in the fish assemblages. Fish counts and seven physical and biological variables were recorded at six sites around the island every spring and fall. Over the study period, a total of 45 fish species from 18 families were recorded, though...

We identified the HindIII restriction site polymorphism of K-casein in cattle reported by Pinder et al. (Animal Genetics 22, 11, 1991) and found an additonal polymorphism (RsaI) in cattle and bison. The HindIII and RsaI restriction sites were mapped and three haplotypes (alleles) were identified. Preliminary screening of 39 cattle and 71 bison revealed one allele restricted to cattle...

A positive relationship exists between fledgling body mass and juvenile survival for some altricial (Krementz et al. 1989, Magrath 1991, Linden et al. 1992) and precocial (Owen and Black 1989, Longcore et al. 1991, Francis et al. 1992) species. Because the energetic demands of migration are high, physiologic condition may be a proximate determinate of juvenile survival in geese. Owen and...

Compared with their Atlantic counterparts, Black-legged Kittiwakes (Rissa tridactyla) in North Pacific colonies are notably unproductive. A large colony on Middleton Island, Alaska, has in most years since 1981 seen complete breeding failure and the population has declined by half. We compared parent-offspring behaviors in this colony during two years that differed in overall breeding...

It is often incorrectly assumed that plutons have a relatively uneventful structural history after emplacement. The 151 Ma Guadalupe Igneous Complex (GIC) in the Foothills Terrane, California, was involved in three post-emplacement events: (1) ∼30° of southwestside-up tilting during ductile regional faulting and contraction, (2) burial of the pluton from ∼4 to 12 km during crustal...

Breeding Black-legged Kittiwakes Rissa tridactyla survived at a mean annual rate of 0.926 in four years at a colony in Alaska. Survival rates observed in sexed males (0.930) and females (0.937) did not differ significantly. The rate of return among nonbreeding Kittiwakes (0.839) was lower than that of known breeders, presumably because more nonbreeders moved away from the study plots...