bluuebunny/crossref_metadata_2025_split huggingface dataset:
MOVEMENTS, HOME RANGE, AND TERRITORIES OF MALE SEA OTTERS OFF CENTRAL CALIFORNIA
Authors: Jameson Ronald J. 
Published: August 2006

AbstractSixty male sea otters (Enhydra lutris) were tagged on the rear flippers with colored tags. Of these, 46 (77%) were resighted. Movements of 127 km were documented for adults and 187 km for subadults. Adults maintained breeding territories that averaged 40.3 ha (n= 10, SE = 4.0). They returned to the same territory seasonally for up to seven consecutive years. Territorial males moved from areas of high male abundance to areas of high female abundance on a seasonal basis. During the winter, 74% of adult males left breeding areas and joined concentrations of males located near the ends of the range. Thirty percent of the subadult males were observed in male groups near the extremities of the range. During the summer and fall, the density of adult males (15/1,000 ha) and adult male to independent otter (non‐pup) ratio (1:5) in female areas was highest. The number of adult males in areas of female abundance was inversely related to the number of dependent pups, perhaps because when pup numbers are low (late summer and fall) the number of estrous females is high. Subadult males may remain in female areas on a year round basis until their second or third year. However, they were not generally associated with adult females.
CHEMICAL RESTRAINT AND ANESTHESIA OF PINNIPEDS: A REVIEW
Authors: Gales Nicholas J. 
Published: August 2006

AbstractDrugs used to restrain and anesthetize pinnipeds have included neuromuscular blocking agents, narcotic analgesics, barbiturates, cyclohexamines, ataractics and inhalational agents. Problems associated with narrow margins of safety, thermoregulatory disturbances, cardiovascular changes and fatalities have excluded all but the cyclohexamines, ataractics and inhalational agents from presently accepted drugs for chemical restraint and anesthesia of pinnipeds. Combinations of tiletamine hydrochloride and zolazepam hydrochloride show great promise for immobilizing some species of pinnipeds in the field and inhalational agents are recommended for surgical anesthesia.
HAUL‐OUT PATTERNS, SITE FIDELITY AND ACTIVITY BUDGETS OF MALE HOOKER'S SEA LIONS (PHOCARCTOS HOOKERI) ON THE NEW ZEALAND MAINLAND
Authors: BEENTJES MICHAEL P. 
Published: August 2006

AbstractDiurnal and seasonal haul‐out patterns, site fidelity and activity budgets of individually identified Hooker's sea lions were studied for two years at Papanui Beach, Otago Peninsula, New Zealand.Fourteen male sea lions were identified. Lengths ranged from 1.65 m–2.28 m and estimated ages from 2‐11 yr. The population consisted of four sexually and socially mature (potentially breeding), eight sexually mature but socially immature and two immature males. Most haul‐outs (95.6%) were by nine identifiable individuals (Residents) returning on a regular basis, suggesting a high degree of site specificity. Emigration and recruitment were low in relation to the length of the study. Daily arrivals (mean = 0844 h, SD = 1.49) and departures (mean = 1802 h, SD = 1.18) indicate nocturnal feeding. During March 1986 sea lions spent 43.8% of each day ashore (= 78% of daylight hours). Numbers of sea lions hauled out declined in both breeding seasons; in 1986/87 this was due to a decrease in haul‐out frequency of resident animals. All but one of these sea lions returned after the breeding season.Sea lions preferentially selected the middle and the extreme ends of the beach as haul‐out sites. During winter use was made of the grass dunes as haul‐out areas.There were significant differences in the frequencies of behavioral activities between summer and winter; more time was allocated to resting in summer.
HARBOR SEAL TRACKING AND TELEMETRY BY SATELLITE
Authors: Stewart Brent S. , Leatherwood Stephen , Yochem Pamela K. , Heide‐Jørgensen Mads‐Peter 
Published: August 2006

AbstractWe tested a satellite Platform Transmitter Terminal (PTT) in the laboratory (on a float and on captive seals) and on a free‐ranging harbor seal in the Southern California Bight to investigate the utility of satellite telemetry in documenting seals’at‐sea behavior and movements. We used records from a microprocessor‐based time‐depth recorder (TDR) to interpret location and diving records from the PTT. For the free‐ranging harbor seal, we obtained at least one uplink during 70% (while the seal was at sea) to 82% (while she was ashore) of satellite passes and at least one location each day. Of 62 locations determined by Service Argos for the free‐ranging seal, 20 were verified from TDR records to have been at sea; these indicated that the seal may have ranged up to 48 km from the haul‐out site, although most locations were within 5 km. The accuracies of locations calculated when the seal was at sea (±15 km) were substantially less than when it was ashore (±1.5 km), thus limiting at‐sea tracking of seals by satellite to rather gross movements. Fewer transmissions were detected and locations calculated when the seal was actively diving than when it was swimming near the surface as it departed from or returned to the haul‐out site. Consequently, average dive durations indicated by the PTT were substantially shorter than those calculated from TDR records. Documentation of foraging areas and detailed at‐sea movements using satellite technology may not be possible for pinnipeds unless PTT‐transmission rates are increased substantially from the 1 per 45 set maximum rate now permitted by Service Argos.
QUANTITATIVE DETERMINATION OF OPTIMUM SUSTAINABLE POPULATION LEVEL
Authors: Gerrodette Tim , DeMaster Douglas P. 
Published: August 2006

AbstractQuantitative methods are reviewed and compared for determining whether a marine mammal population is at an optimum sustainable population (OSP) level, a management goal specified by the U.S. Marine Mammal Protection Act. Methods of OSP determination fall into two general types: those that require an estimate of a population's maximum net productivity level (e.g., the back‐calculation method) and those that do not (e.g., dynamic response analysis). The two types differ in the data they require and in whether they determine OSP with respect to present or historical carrying capacity. Back‐calculation and dynamic response analyses are compared using data on the California gray whale (Eschrichtius robustus.) Marine mammal monitoring programs should be designed to detect trends in both the abundance of a population and its condition relative to carrying capacity, because both quantities are involved in the definition of OSP. The value of using both abundance and condition indices in an assessment is illustrated with data on the northern fur seal (Callorhinus ursinus.)
DENSITY DEPENDENCE IN NORTHERN FUR SEALS (CALLORHINUS URSINUS)
Authors: Fowler Charles W. 
Published: August 2006

AbstractThis paper summarizes, updates, and interprets information on density‐dependent dynamics of populations of the northern fur seal (Callorhinus ursinus). Density‐dependent changes observed in these populations have involved various aspects of growth (body length, body weight, tooth weight, and size of other skeletal parts, especially the skull), survival, age at maturation, incidence of disease, and time spent foraging. For the population of northern fur seals on St. Paul Island of the Pribilof Islands, which was observed during a major increase and during two significant declines, density‐dependent changes that occurred during the growth of the population were reversed during the declines. The Robben Island population in the western Pacific declined after 1965, and the decline was accompanied by changes similar to those observed during the declines on the Pribilof Islands. Although data are not available for all age and sex classes, it appears that most or all components of the populations exhibit similar changes. The overall implication of these changes is that current populations on Robben Island and the Pribilof Islands are reduced to levels below what could be supported by the resources available in their environments. Density dependence for this species is consistent with that of other large mammals, specifically in that vital rates for fur seals ate related to density in a nonlinear fashion.
THE MOST NORTHERLY HARBOR SEAL,PHOCA VITULINA, AT PRINS KARLS FORLAND, SVALBARD
Authors: Prestrud Pål , Gjertz Ian 
Published: August 2006

AbstractThe harbor seal (Phoca vitulina) has its northernmost distribution at the Norwegian arctic archipelago of Svalbard. Little information exists on this particular harbor seal population. The present paper summarizes this information, and gives the result of surveys of harbor seals conducted in Svalbard in 1984, 1985 and 1987. These surveys show that harbor seals in Svalbard are limited to the area around Prins Karls Forland, the westernmost island in the archipelago. The harbor seal population at Prins Karls Forland numbers at least five to six hundred animals.
ENTANGLEMENT IN MAN‐MADE DEBRIS OF ANTARCTIC FUR SEALS AT BIRD ISLAND, SOUTH GEORGIA
Authors: Croxall J. P. , Rodwell S. , Boyd I. L. 
Published: August 2006

AbstractNeck collars of man‐made marine debris were seen on 208 Antarctic fur seals (and removed from 170) during the 142 days of the 1988–1989 pup‐rearing season at Bird Island, South Georgia. This represents at least 0.1% of the total Bird Island population and a minimum of 0.4% of animals in the best covered areas; a maximum value might approach 1%. Polypropylene straps (packaging bands) formed 59% of collars, nylon string (16%), fishing net (13%) and six other materials comprised the rest. Males accounted for 71% of entanglements, 88% of which were of young (1–4 yr old) animals; females accounted for 64% of animals older than this. Obvious physical injury was being caused to 30% of animals and only on 19% of animals was the collar loose enough potentially to come off. The magnitude of the problem at South Georgia is similar to that with northern fur seals at the Pribilof Islands, where a significant population decline has occurred concurrently. Antarctic fur seals are still increasing in numbers but stricter controls on the jettisoning of debris into the Southern Ocean ate needed if the entanglement problem is not to increase beyond the level of a potential threat.
Books
Authors: Shaughnessy Peter 
Published: August 2006

AbstractBook review in this ArticleTHE PINNIPEDS: SEALS, SEA LIONS, AND WALRUSES. M. Riedman. University of California Press, Berkeley. ISBN O‐520‐06497‐6. 439 pp. 1990. Price $29.95 (U.S.) (hard‐bound).
DIVING PATTERNS OF NORTHERN ELEPHANT SEAL BULLS
Authors: DeLong Robert L. , Stewart Brent S. 
Published: August 2006

AbstractWe used small microprocessor‐based, time‐depth recorders to document the diving patterns of six adult male northern elephant seals (Mirounga angustirostris) from San Miguel Island, California. The recorders stored measurements of hydrostatic pressure every 30 or 60 set while the seals were at sea for 107 to 145 d in spring and early summer; collectively, over 36,000 dives were recorded. Seals dove continually while at sea, most often to depths of 350–450 m although two seals had secondary modes at about 700–800 m; maximum depths for two seals of 1,333 m and 1,529 m are the deepest yet measured for air‐breathing vertebrates. Seals were submerged about 86% of the time they were at sea, rarely spending more than 5 min at the surface between dives; 99% of all post‐dive surface intervals were shorter than 10 min. Dives averaged 21–24 min, the longest was 77 min. The uninterrupted patterns of long dives punctuated by brief surface periods suggest that most if not all dives were well within these seals’aerobic limits. Dives of bulls were, on average, about 18% longer than those published earlier for cows, evidently because of the substantially greater body mass of bulls and allometric scaling of dive endurance. Dive depths and dive durations varied seasonally; depths were greatest in spring, durations greatest in early summer. During each season dives were deepest during the day and shallowest at night except for the sixth seal whose consistently shallow dives (50–150 m) in spring were independent of time of day. Prey remains recovered by lavage from seals’stomachs were primarily of vertically migrating, epi‐ and meso‐pelagic squid. The die1 patterns in dive depths suggest that five seals dove to and foraged in the offshore mesopelagic zone, pursuing those vertically migrating prey. The sixth seal behaved similarly in early spring and early summer but may have foraged in nearshore epibenthic habitats in spring.
SEA OTTER DIETS IN A DECLINING POPULATION IN ALASKA
Authors: Green Gregory A. , Brueggeman John J. 
Published: August 2006

AbstractDiet of sea otters (Enhydra lutris) using a haulout site on the north side of the Alaska Peninsula was determined from 50 scats. Dominant prey species were mussels (Mytilus edulis), followed by three species of clams (Siliqua spp., Spisula polynyma, and Tellina lutea), sand dollars (Echinarachnius parma), and helmet crabs (Telmessus cheiragonus). Our results support preliminary findings by Cim‐berg et al. (1984) that this sea otter population preys heavily on mussels and that the presence of low caloric value sand dollars in their diet is significant. Coupled with population estimates, our results also provide evidence that this population of sea otters may be declining due, in part, to overdepletion of food resources.
THE NARWHAL, MONODON MONOCEROS, IN THE NORWEGIAN HIGH ARCTIC
Authors: Gjertz Ian 
Published: August 2006

AbstractNarwhals (Monodon monoceros) are known to frequent the waters of the Norwegian arctic archipelago of Svalbard. An attempt is made to summarize narwhal observations from the Svalbard area, and from this to deduce their distribution. Observations have been gathered from the literature, sealing vessel log books and official statistics. Interviews have also been conducted with residents of Svalbard. I con&de that narwhals are most frequently observed in the area off the north‐west corner of Spitsbergen.
OCCURRENCE AND BEHAVIOR OF THE SOUTHERN RIGHT WHALE DOLPHIN LISSODELPHIS PERONII OFF NAMIBIA
Authors: Rose Barrie , Payne Andrew I. L. 
Published: August 2006

AbstractThe southern right whale dolphin Lissodelphis peronii is a seldom seen cetacean of southern latitudes. Off southern Africa, observations have been made predominantly in the major upwelling area off Lüderitz, Namibia, but the species has now also been seen south of the Orange River in South African waters. Sightings for the years 1980–1990 are documented and they reveal that L. peronii occurs off southern Africa both inshore and offshore and throughout the year. An opportunity for extended observation in January 1989 afforded the opportunity to record some interesting behavior patterns.
A PATERNITY TEST CASE FOR THE KILLER WHALE (ORCINUS ORCA) BY DNA FINGERPRINTING
Authors: Hoelzel A. Rus , Ford John K. B. , Dover Gabriel A. 
Published: August 2006

AbstractThe minisatellite DNA profiles from four captive killer whales (two adult males, a female and her calf) were compared to determine paternity between two potential fathers. One of the males was clearly excluded, while the other shared all paternal bands with the calf. The background of this technique, and its potential applications in captive breeding programs and field studies are discussed.
RATE OF INCREASE, 1978–1988, OF BOWHEAD WHALES, BALAENA MYSTICETUS, ESTIMATED FROM ICE‐BASED CENSUS DATA
Authors: Zeh Judith E. , George John C. , Raftery Adrian E. , Carroll Geoffry M. 
Published: August 2006

AbstractThe number of bowhead whales, Balaena mysticetus, passing within viewing range of the ice‐based census at Point Barrow, Alaska, during spring migrations from 1978 to 1988 is estimated from the visual census data. The trend in the annual numbers yields an estimated rate of increase of 3.1% per year with a 95% confidence interval ranging from 0.1% to 6.2% for the Bering‐Chukchi‐Beaufort Seas bowhead stock during this period. Alternative treatments of the data suggest less precise or somewhat lower estimates, but all results indicate that the stock was increasing.
THE ROLE OF PREDATION IN THE ECOLOGY OF THE RINGED SEAL IN BARROW STRAIT, NORTHWEST TERRITORIES, CANADA
Authors: Hammill M. O. , Smith T. G. 
Published: August 2006

AbstractPredation on ringed seals (Phoca hispida) was examined in Barrow Strait between March and May 1984 to 1986. Polar bears were the most important predator. Evidence of bear predation was observed at 18–30% of the ringed seal subnivean structures we located. Ten to 24% of predation attempts were successful, with pups making up 75% to 100% of the seals killed. Bears killed an average of 0.08 to 0.51 seals/km2, which comprised 8 to 44% of the estimated annual pup production. Bears were successful on average in 11.3% of their attempts to kill pups hidden inside birth lairs. On southeast Baffin Island where snow was soft and pups were exposed, bears were successful in 33.5% of their attempts to kill a seal. Negative correlations were found between mean snow depth and predation by polar bears (r= ‐0.896, P= 0.04, n= 5) in 1985, and between snow depth and the number of predation attempts (r= ‐0.613, P= 0.02, n= 14) in 1986.
A METHOD FOR ESTIMATING MASS OF LARGE PINNIPEDS
Authors: Haley Michael P. , Deutsch Charles J. , Boeuf Burney J. Le 
Published: August 2006

AbstractFifty‐two male elephant seals were weighed and photographed at Año Nuevo State Reserve, California, to establish a predictive relationship between photographically measured morphological variables (length, side area, and girth area) and body mass. Regression of mass on these variables revealed that side area, roughly equivalent to a longitudinal cross‐section, was the most useful single variable for predicting mass, and that adding the other two variables to side area slightly improved the accuracy of the photogrammetric technique. Curvilinear regressions based on a power model provided the best predictive relationships. This technique may prove useful for estimating body mass of other pinnipeds.
AN EPIZOOTIC OF FLORIDA MANATEES ASSOCIATED WITH A DINOFLAGELLATE BLOOM
Authors: O'Shea Thomas J. , Rathbun Galen B. , Bonde Robert K. , Buergelt Claus D. , Odell Daniel K. 
Published: August 2006

AbstractOver a 10‐wk period in early 1982, 39 Florida manatees (Trichechus manatus latirostris) were found dead in the lower Caloosahatchee River and nearby waters of southwestern Florida. Two were killed by boats. The remainder showed no evidence of trauma. Lesions indicative of infectious agents were not identified, and bacteriological and contaminant residue findings were unremarkable. Nonspecific lesions of congestion and hemorrhage were identified in brain tissue. Numerous reports were also received of manatee morbidity. Some distressed manatees showed no biochemical lesions in clinical analyses of blood samples and recovered quickly. Timing of manatee illnesses coincided with fish and double‐crested cormorant (Phalacrocorax auritus) mortality and morbidity. A widespread bloom of the dinoflagellate red tide organism (Gymnodinium breve) also coincided with these incidents. G. breve produces potent neurotoxins (brevetoxins). Circumstantial evidence links these events, and possible routes of exposure may include ingestion of filter‐feeding ascidians. Ecological conditions that magnified the extent of the epizootic included an early dispersal of manatees into the area from a nearby winter aggregation site and unusually high salinities that facilitated the inshore spread of the red tide bloom. Management responses to future episodes of red tide in manatee areas are suggested.
EFFECTIVENESS OF VARIOUS CATTLE EAR TAGS AS MARKERS FOR WEDDELL SEALS
Authors: Testa J. Ward , Rothery Peter 
Published: August 2006

AbstractMethods for estimating tag loss and sightability of tags are presented. Rates of tag loss were estimated for metal and several varieties of plastic cattle ear tags in a long‐term population study of Weddell seals. Tags were lost at a higher rate in the first year after application than in subsequent years, and pups lost tags at a higher rate than older seals given the same tag types. Medium‐sized plastic tags (Dalton, Allflex and Fearing) were retained at higher rates and were overlooked less frequently than metal tags on adult seals. Dalton Jumbo Rototags showed the lowest loss rates on pups in comparison to larger, flexible plastic tags, but were harder to read in the field.
CETACEAN LENS ZONES OF DISCONTINUITY—INDICES OF HEALTH AND DEVELOPMENT
Authors: Dawson William W. , Hope G. M. , Dawson Judyth C. , Nachtigall Paul E. , Schroeder J. Pete 
Published: August 2006

AbstractDetails of the lenses of eyes in two living Tursiops truncatus and one Grampus griseus were photographed. In the laboratory the lens cortex could be retro‐illuminated by a fundus camera and spatially periodic stria could be visualized, in large part because of the highly developed tapetum of the cetacean eye. Varying spaces were present between the stria. On a three‐dimensional basis, the best analogy is the layering of an onion. One photograph was digitized giving good quantification of the sizes of the layers and their number. Similar, but less easily resolved, lens cortex organization has been described frequently in humans as “zones of optical discontinuity.” These have been explained as a periodic temporal consequence of normal aging with layer thickness depending on general health. We found that young cetaceans have few “zones” and older cetaceans have many. Lens zones measurement may be developed to Provide objective data on history of cetacean health and age.
AN ANALYSIS OF CALIFORNIA SEA OTTER (ENHYDRA LUTRIS) PELAGE AND INTEGUMENT
Authors: Williams Thomas D. , Allen D. Diane , Groff Joseph M. , Glass Robert L. 
Published: August 2006

AbstractThe sea otter is associated with a cold, marine habitat, has no insulating fat layer, and relies on its fur layer for insulation. Soiled pelage provides inadequate insulation and can lead to hypothermia and death. Information on sea otter pelage, the surface and bound lipids found in the pelage, and histology of the integument is thus relevant to the development of rehabilitation and management techniques for sea otters soiled with oil. We present detailed data on the sea otter pelage and integument, including hair bundle density (737–2,465 bundles per cm2), hair density per bundle (19–91.1), total hair density (26,413–164,662 hairs per cm2), guardhair length (8.2–26.9 mm), underfur length (4.6–15.8 mm), guardhair diameter (44.0–106.0 μ), underfur diameter (7.6–11.9 μ), angle of hair with respect to the skin (61.9°‐ 84.3°) and structure of individual hairs as seen with a scanning electron microscope. The hydrocarbon squalene was found to be the major component of the lipids associated with the pelage. Various layers of skin from eight sites on a single animal are described histologically. With the exception of density of the hair coat, sea otter integument is similar to that of domestic carnivores.
PHOCINE DISTEMPER VIRUS INFECTION IN HARP SEALS (PHOCA GROENLANDICA)
Authors: Markussen Nina Hedlund , Have Per 
Published: August 2006

AbstractAntibodies against phocine distemper virus were found in liver and serum specimens of harp seals from the Barents Sea and north of Jan Mayen (West Ice) in 1987 and 1989. By immunoperoxidase testing, antibodies against phocine distemper virus could be demonstrated in 34 of 74 liver specimens (46%) from 1987 and in 44 of 126 liver specimens (35%) from 1989. The prevalence of neutralizing serum antibodies against phocine distemper virus was found to be 98% in 1989. Both findings clearly demonstrate the presence of a widespread infection with phocine distemper virus or a closely related virus in harp seals. The significance of these findings to the recent outbreak of phocine distemper virus infection in harbor seals in Northwestern Europe is discussed and it is concluded that there may be an epizootiological link between this outbreak and the large migration of harp seals in 1987.