The Pacific walrus (Odobenus rosmarus divergens) population is an important ecological and economic resource of the Bering Sea region. We describe population change, beginning with a low in 1950, through a high in about 1980, and ending in 1989. Estimates of abundance for the years after 1989 were not attempted due to the lack of harvest data and other population parameters. Selective hunting practices resulted in biased data regarding population composition and reproductive performance. Rates of reproduction had to be estimated from ovarian data, which indicated a dramatic drop in the 1980s. High harvests in the 1980s likely contributed to a decline in the population, but uncertainties as to accuracy of population estimates and other data raise reasonable doubts, especially with respect to the number of males, for which the most recent (1985) population estimate suggests a sharp decline. Past population estimates were revised upwards to compensate for walruses underwater and not seen in aerial surveys. The weaknesses in the available data make it clear that effective management of the population will require many improvements in collection of data regarding harvests, population structure, reproduction, and population trend.

Analysis of stomach contents of ringed seals (Phara hispidu) collected at eight locations along the Alaskan coast showed significant seasonal and regional difrerences in diet. During the spring-summer period saffron cod (Eleginus gmcilis) was the most important food item in the nearshore zone of the northeastern Bering and southeastern Chukchi Seas. In that period shrimps (Pundulus spp., Eualus spp., Lebbeus polaris, and Crungon septc~rnspinssu) were the major food in the northcentral Bering Sea, hyperiid amphipods (Pamthemisto libellula) in the central Beaufort Sea and euphausiids (Tlzysur~oessa spp.) in the boundary region (Barrow area) between the Chukchi and Beaufort seas. During late summer-early autumn hyperiid amphipocts were important foods in the central Beaufort and the southeastern Chukchi. The autumn diet of seals in Norton Sound included mainly sagron cod During winter-early spring Arctic cod (Boreogucius saida) predominated the diet at all localities. During spring and early summer in the northeastern Bering and southeastern Chukchi seas the amount of saffron cod consumed was directly correlated with age. In the Beuufort Sea during autumn and winter Arctic cod were eaten in similar amounts by all age-classes. An analysis of the energy value and quantities of prey consumed indicates that prey species that occur in concentrations (Arctic and saftion cods, hyperiid amphipods, euphausiids and some shrimps) are of particular importance in the annual nutrition of ringed seals. These seals may be food limited in areas and during times when these kinds of prey are not available. . 1980. Variability in the diet of ringed seals, Plzoeu kispidu, in Alaska. Can. J. Fish. Aquat. Sci. 37: 2254-2261. 11 existe des differences saisonnikres et regionales nlarquCes de regime alimentaire chez le phoque an11elC (Plzow lzispidu), comme le dCmontre I'analyse des contenus stomacaux d'Cchantillons recueillis h huit endroits le long de la c8te de 1'Alaska. Dans la pkriode printemps-6tC, la morue arctique (Elt>piilus gmcilis) est l'aliment le plus important d+ns la zone littorale du nordest de la mer de Bering et du sud-est de la rner de Tchouktche. A cette Cpoque, les crevettes (Paizdalus spy., Eualus spp., Lebbeus polaris et Cran,qon septemspinosa) constituent l'aliment principal dans le centre-nord de la rner de Bering, les amphipodes hypkriides (P~~mthc~rnisto libtdlula) dans le centre de la rner de Beaufort et les euphausides (Tl~ysurzoessa spp.) dans la region frontalikre (region de Barrow) entre les mers de Tchouktche et de Reaufort. En fin d'et6 et dCbut d'automne, les amphipodes hypkriides sont des aliments importants dans le centre de la rner de Beaufort et le sud-est de la mer de Tchouktche. Bans la baie Norton, le rCgime automnal des phoques est constituk en grande partis par de la morue arctique. En hiver et au debut du printemps, le saida (Boreogadus saida) prCdomine dans le regime h tous lec endroits. Au printemps et debut de l'kti, la quantite de rnorue arctique consomm& est fonction directe de ]'Age dans le ...

The theory of attentional inertia holds that attentional engagement increases over the time course of a look at television and that this engagement rapidly dissipates when the look ends. The theory was tested in a study of 41 undergraduate students' viewing of 2 hours of videotaped dramatic television programs and associated commercials. The main results were that (a) inertial engagement sustains looks across boundaries between programs and commercials, (b) inertial engagement does not carry over from one look to the next, (c) inertial engagement was associated with greater recognition memory for TV content, and (d) as predicted by a model of attentional inertia, look length distributions are approximately lognormal and hazard functions are nonmonotonic with a peak at about 1 second.

The abundance of harbor seals (Phoca vitulina richardii) has declined in recent decades at several Alaska locations. The causes of these declines are unknown, but there is concern about the status of the populations, especially in the Gulf of Alaska. To assess the status of harbor seals in the Gulf of Alaska, we conducted aerial surveys of seals on their haul‐out sites in August‐September 1996. Many factors influence the propensity of seals to haul out, including tides, weather, time of day, and time of year. Because these “covariates” cannot simultaneously be controlled through survey design, we used a regression model to adjust the counts to an estimate of the number of seals that would have been ashore during a hypothetical survey conducted under ideal conditions for hauling out. The regression, a generalized additive model, not only provided an adjustment for the covariates, but also confirmed the nature and shape of the covariate effects on haul‐out behavior. The number of seals hauled out was greatest at the beginning of the surveys (mid‐August). There was a broad daily peak from about 1100–1400 local solar time. The greatest numbers were hauled out at low tide on terrestrial sites. Tidal state made little difference in the numbers hauled out on glacial ice, where the area available to seals did not fluctuate with the tide. Adjusting the survey counts to the ideal state for each covariate produced an estimate of 30,035 seals, about 1.8 times the total of the unadjusted counts (16,355 seals). To the adjusted count, we applied a correction factor of 1.198 from a separate study of two haul‐out sites elsewhere in Alaska, to produce a total abundance estimate of 35,981 (SE 1,833). This estimate accounts both for the effect of covariates on survey counts and for the proportion of seals that remained in the water even under ideal conditions for hauling out.

ABSTRACT. Current and historical information about food habits of bearded seals, Erignurhus burbutus, are presented. Shrimps, crabs, and clams are overall the most important prey. Proportions of different prey in the diet vary with age of seals, location, and time of year. Foods of male and female seals are similar. Young seals eat proportionally more shrimps than do older animals. Recently, clams were important in the diet only in Norton Sond and near Wainwright, and only during late spring and summer. Greatest quantities of food were found in stomachs of seals which had eaten mostly clams. In Bering Strait, seals taken in spring 1958 and 1967 had consumed large quantities of clams, but this item was only a minor fraction of foods in 1975-79.