bluuebunny/crossref_metadata_2025_split huggingface dataset:
DIVING BEHAVIOR OF THE SAIMAA RINGED SEAL (PHOCA HISPIDA SAIMENSIS NORDQ.)
Authors: Hyvärinen Heikki , Hämäläinen Esa , Kunnasranta Mervi 
Published: August 2006

AbstractThe activity and diving patterns of four adult Saimaa ringed seals (Phoca hispida saimensis, a landlocked subspecies living in Lake Saimaa, Finland) were examined during spring, summer, and autumn by the use of VHF‐transmitters. Over 17,000 dives were registered. The duration of the dives and diving patterns differed among individuals. The mean duration of dives increased from spring to autumn; e.g., in one individual the mean dive duration increased from 6 min in June to 10.5 min in October. The haul‐out periods of one individual in May to early June made up 46.2% of its total activity budget, but in another individual in July to August the haul‐out periods made up only 11% of the budget and the seal was submerged for 80% of the time. Periods of successive long duration dives (>10 min) were observed in three individuals in summer and autumn. The longest dive measured was 23 min. The duration of the periods containing long dives was often over three hours (maximum six hours) and the mean duration of the dives about 15 min. These long duration dives are assumed to be aerobic resting dives. Generally, the dives of the Saimaa ringed seal appear to be of longer duration than previously assumed.
RETINAL GANGLION CELL SIZE AND DISTRIBUTION PREDICT VISUAL CAPABILITIES OF DALL'S PORPOISE
Authors: Murayama Tsukasa , Somiya Hiroaki , Aoki Ichiro , Ishii Takeo 
Published: August 2006

AbstractThe structure of the retina, the distribution of ganglion cells, and the extent of the tapetum lucidum were studied in Dall's porpoise (Phocoenoides dalli) with the aim of understanding the role vision plays in this species of cetacean. The basic organization of the retina was similar to that of other vertebrates. Average ganglion cell size was 21.5 μm. The distribution of the ganglion cells in the retina was not even and there were two high‐density areas, one in the temporal and one in the rostral part of the retina. Retinal resolving power was estimated using a terrestrial animal model incorporating the density of ganglion cells and other morphological data. The resolving power in the right eyes of two individuals was 2.60 and 2.64 cycles per degree. These values were close to those of other oceanic cetaceans, but inferior to those of terrestrial mammals. On the basis of amino acid analyses, it was shown that the choroid tapetum lucidum in Dali's porpoise contained collagen. The tapetum lucidum was thick at the fundal but thin at the peripheral part of the choroid.
MORBILLIVIRUS INFECTION IN TWO SPECIES OF PILOT WHALE (GLOBICEPHALA SP.) FROM THE WESTERN ATLANTIC
Authors: Duignan Padraig J. , House Carol , Geraci Joseph R. , Early Greg , Copland Heather G. , Walsh Michael T. , Bossart Gregory D. , Cray Carolyn , Sadove Samuel , Aubin David J. ST. , Moore Michael 
Published: August 2006

AbstractWe report evidence of enzootic morbillivirus infection among long‐finned, Globicephala melas, and short‐finned, G. macrorhynchus, pilot whales in the western Atlantic. A retrospective serologic survey, using five morbilliviruses, was carried out on 99 G. melas from 14 stranding events between 1982 and 1993 and from 25 G. macrorhynchus stranded in 5 events between 1986 and 1994. A blood sample was also obtained from an adult G. melas by‐caught in the western North Atlantic. Tissues were collected from 24 G. melas and 15 G. macrorhynchus for histology and immunoperoxidase staining. Neutralizing antibody titers were found in 92 (92%) of 100 G. melas and 16 (64%) of 25 G. macrorynchus, and titers were highest against cetacean morbilliviruses. Seroprevalence was similar between age classes and sexes. The earliest evidence of infection was in a G. melas that stranded in 1982. Stable antibody titers were observed in pilot whales under rehabilitation for up to eight months. Clinical disease consistent with morbillivirus pneumonia was detected in a G. melas calf. Immunoperoxidase staining confirmed that viral antigen was present in the lesions.We propose that enzootic infection in pilot whales is facilitated by population size, social structure, and migration patterns. Furthermore, through mixing with other odontocetes, pilot whales could act as vectors through the Atlantic. Clinical morbillivirus infection may precipitate mass strandings of highly social odontocetes.
SKIN BIOPSY SAMPLING OF BELUGA WHALE CARCASSES: ASSESSMENT OF BIOPSY DARTING FACTORS FOR MINIMAL WOUNDING AND EFFECTIVE SAMPLE RETRIEVAL
Authors: PATENAUDE N. J. , WHITE B. N. 
Published: August 2006

AbstractDifferent combinations of biopsy tip lengths (20, 25 mm) and diameters (5, 6, 7 mm), crossbow draw weights (23, 45, 68 kg) and distances (1.5–15 m) were tested on fresh beluga carcasses to determine factors affecting the success of biopsy retrieval and the extent of wounding. Tips with smaller diameters and longer lengths were found to be more likely to retrieve a skin sample, while the draw weight of the crossbow had a significant effect on the severity of the wound. The samples obtained from all biopsy darts tested yielded sufficient amounts of DNA for genetic analysis (20–109 μg) with the highest yield coming from the germinativum spinosum layer. For beluga whales we recommend using a tip of 5 mm in diameter, 25 mm in length, and a draw weight of 23 kg at close range.
LIFE IN THE FAST LANE: THE LIFE HISTORY OF HARBOR PORPOISES FROM THE GULF OF MAINE
Authors: Read Andrew J. , Hohn Aleta A. 
Published: August 2006

AbstractWe describe the life history of harbor porpoises in the Gulf of Maine by examining 239 animals killed in gill net fisheries and comparing these findings with the results of previous studies from the Bay of Fundy. Most female porpoises matured at age three and became pregnant each year thereafter. Reproduction was strictly seasonal, with ovulation, conception, and parturition occurring in the spring and early summer. The oldest specimen in the sample was 17 yr of age, but most individuals were younger than 12. The findings are similar to those of earlier studies from the Bay of Fundy and support the hypothesis that these animals form a single population. Harbor porpoises represent one end of a continuum of odontocete life histories that spans a wide diversity of strategies. In comparison with other, large odontocetes, harbor porpoises mature at an earlier age, reproduce more frequently, and live for shorter periods.
BODY TEMPERATURE IN THE NEWBORN SOUTHERN ELEPHANT SEAL, MIROUNGA LEONINA, AT MACQUARIE ISLAND
Authors: Little G. J. 
Published: August 2006

AbstractNewborn southern elephant seal pups were reported by Laws (1953) to be “to some extent poikilothermic at birth.” Rectal temperatures of known age southern elephant seal pups were recorded during the 1985 pupping season at Macquarie Island. The mean pup rectal temperature was found to be 381°C ± 0.1°C SEM (n= 131, range = 36.5°‐39.1°C). Pups at two hours, six hours, and one day after birth had significantly higher rectal temperatures than pups two, three, or four days of age. Rectal temperatures of neonatal southern elephant seals were within the range observed for other pinnipeds, (but never as low as the 31°C previously observed for southern elephant seals at Signy Island in 1953). A significant though weak positive correlation was found between pup temperature and body weight. However, no correlation between pup temperature and age or any environmental factor was found. These observations demonstrated that southern elephant seal pups at Macquarie Island are homeothermic, rather than heterothermic from birth.
THE CLICK‐SOUNDS OF NARWHALS (MONODON MONOCEROS) IN INGLEFIELD BAY, NORTHWEST GREENLAND
Authors: Miller Lee A. , Pristed John , Møshl Bertel , Surlykke Annemarie 
Published: August 2006

AbstractWe studied the sounds of narwhals (Monodon monoceros) foraging in the open waters in Northwest Greenland. We used a linear, vertical array of three hydrophones (depth 10 m, 30 m, 100 m) with a fourth hydrophone (depth 30 m) about 20 m from the vertical array. A smaller fifth hydrophone (depth 2 m) allowed for registering frequencies up to 125 kHz (± 2 dB) when signals were recorded at 762 mm/set on an instrumentation tape recorder. Clicks were the prevalent signals, but we heard whistles occasionally. We separated the clicks into two classes: click trains that had rates of 3‐10 clicks/sec and click bursts having rates of 110‐150 clicks/sec. The spectra of train clicks had maximum amplitudes at 48 ± 10 kHz and a duration of 29 ± 6 psec. The spectra of burst clicks had maximum amplitudes at 19 ± 1 kHz and a duration of 40 ± 3 psec. By analogy with other dolphin species, narwhals presumably use the clicks for echolocation during orientation and for locating prey. The narwhal click patterns resemble those of insectivorous bats. Click trains might correspond to bat searching signals and click bursts to the bat's terminal “buzz”, emitted just before prey capture.
PLASMA VASOPRESSIN LEVELS AND WATER CONSERVATION IN FASTING, POSTWEANED NORTHERN ELEPHANT SEAL PUPS (MIROUNGA ANGUSTIROSTRIS)
Authors: Ortiz Rudy M. , Adams Sean H. , Costa Daniel P. , Ortiz C. Leo 
Published: August 2006

AbstractNorthern elephant seal pups (Mirounga angustirostris) use several physiological mechanisms to conserve water during their 8‐ 12‐wk postweaning fast. Urine was analyzed from five animals and plasma from four of those animals was sampled serially throughout the postweaning period to quantify changes in urine concentrating ability and electrolyte homeostasis at various stages of the fast (Early = 1‐4 wk, Mid = 4‐7 wk, Late = 7‐10 wk). Plasma osmolarities stayed relatively constant at 301.6 f 13.1 mOsm/kg. Urine osmolarities ranged from 1,053.5 ± 78.6 mOsm/kg (Early), to 1,585.0 ± 136.7 mOsm/kg after eight weeks, dropping to 1,214.3 ± 349.6 mOsm/kg (Late). Urine concentrations for Na+ and K+ early in the fast were 55.0 ± 14.6 mM and 180.8 ± 48.6 mM, respectively, declining to 8.2 ± 3.3 mM and 91.4 ± 29.0 mM later. Plasma vasopressin concentrations ranged from 34.8 ± 18.2 pg/ml (Early) to 4.8 ± 1.3 pg/ml (Late). The pups appear to conserve their body water by producing a concentrated urine, thus reducing urinary water loss. The significance of the antidiuretic role of vasopressin in the conservation of body water in these pups could not be conclusively determined from the results.
SUMMER FEEDING HABITS OF DALL'S PORPOISE, PHOCOENOIDES DALLI, IN THE SOUTHERN SEA OF OKHOTSK
Authors: Walker William A. 
Published: August 2006

ABSTRACTStomach contents were analyzed from 85 Dall's porpoises, Phocoenoides dalli, taken in the southern Sea of Okhotsk during the summer of 1988. Thirteen species of fish and five species of cephalopods were identified. Fishes comprising 9 families were predominant and made up 79.9% of the total number of prey, with an overall occurrence in the stomachs of 100%. Three families of cephalopods made up 20.1% of the total number of prey ingested, with an overall occurrence of 74%. The Japanese pilchard, Sardinops sagax melanostictus, was the primary prey and represented 72.0% of the total prey in 97.3% of the stomachs examined. The gonatid squid, Berryteuthis magister, ranked second and made up 16.9% of the total prey in 61.6% of the stomachs. Walleye pollock, Theragra chalcogramma, was the third most abundant prey item consumed and represented 6.0% of the total, with an occurrence of 53.4%. Composition of the sample by the calculated total mass and caloric intake supports the numeric findings on the relative importance of the three major prey species to the DaIl's porpoise diet. The Japanese pilchard was clearly dominant using these indices and constituted 65.4% of the total mass and 80.7% of the caloric intake. Berryteuthis magister made up 26.8% of the mass and 15.5% of the caloric intake. Walleye pollock contributed the least to the diet with 7.9% of the total mass and 3.8% of the caloric intake. Volumetric data indicate that porpoises are feeding heavily on Japanese pilchard throughout the daylight hours. Berryteuthis magister was probably fed upon in the late night or early morning hours. Occurrence of both Dall's porpoise and Japanese pilchard in the coastal waters of the southern Sea of Okhotsk is seasonal. The summer movements of Dall's porpoise into this region may be related to the seasonal migration and abundance of the Japanese pilchard.
LIFE HISTORY OF FRASER'S DOLPHIN, LAGENODELPHIS HOSEI, BASED ON A SCHOOL CAPTURED OFF THE PACIFIC COAST OF JAPAN
Authors: AMANO Masao , Miyazaki Nobuyuki , Yanagisawa Fumio 
Published: August 2006

ABSTRACTLife history of Fraser's dolphin, a little known delphinid species, was examined based on 108 specimens from a school captured by the driving fishing method in Japan. The sex ratio was approximately 1:1, and mature dolphins of both sexes formed the bulk of the school. The oldest animals were two males and a female of 17.5 yr. Age and body length at sexual maturity were estimated at 7–10 yr and 220–230 cm in males and 5–8 yr and 210–220 cm in females. Mature males were larger in body length than mature females and showed apparent secondary sexual features: deepening of the tail stock and widening and darkening of the lateral dark stripe. The annual ovulation rate was 0.49. The estimated neonatal length (110 cm) predicts a gestation period of about 12.5 mo and calving peaks in spring and probably also in fall. The calving interval was estimated to be about 2 yr. These life history parameters are similar to those of the striped and pantropical spotted dolphins, except for longevity. The reproductive rate of this species may be lower than that of other pelagic delphinids, if the observed shorter longevity is real.
INTERCHANGE AND ISOLATION OF HUMPBACK WHALES OFF CALIFORNIA AND OTHER NORTH PACIFIC FEEDING GROUNDS
Authors: Calambokidis John , Steiger Gretchen H. , Evenson Joseph R. , Flynn Kiirsten R. , Balcomb Kenneth C. , Claridge Diane E. , Bloedel Prentice , Straley Janice M. , Baker C. Scott , Ziegesar Olga VON , Dahlheim Marilyn E. , Waite Janice M. , Darling James D. , Ellis Graeme , Green Gregory A. 
Published: August 2006

ABSTRACTHumpback whales feed in several high‐latitude areas of the North Pacific. We examined the interchange of humpback whales between one of these areas, off California, and those in other feeding grounds in the eastern North Pacific:. Fluke photographs of 597 humpback whales identified off California between 1986 and 1992 were compared with those off Oregon and Washington (29); British Columbia (81); southeastern Alaska (343); Prince William Sound, Alaska (141); Kodiak Island, Alaska (104); Shumagin Islands, Alaska (22); and in the Bering Sea (7). A high degree of interchange, both inter‐and intrayear, was found among humpback whales seen off California, Oregon, and Washington., A low rate of interchange was found between British Columbia and California.: two whales seen near the British Columbia/Washington border were photographed off California in a different year, No interchange was found between California and the three feeding areas in Alaska. Humpback whales off California, Oregon, and Washington form a single intermixing feeding aggregation with only limited interchange with areas farther north. These findings are consistent with photographic identification studies in the North Atlantic and with genetic studies in both the North Atlantic and North Pacific.
UNDERSTANDING AND INTERPRETING HEMATOCRIT MEASUREMENTS IN PINNIPEDS
Authors: Castellini J. M. , Meiselman H. J. , Castellini M. A. 
Published: August 2006

ABSTRACTHematocrit data are relatively easily obtained from blood samples of pinnipeds but differences in methodology and variable physiological conditions of the subjects can significantly alter their values. This two‐fold problem makes comparative data and modeling efforts difficult. To quantify the difficulty of obtaining accurate and representative hematocrit values in pinnipeds, hematocrit was measured by both microcentrifugation and Coulter counter methods in a range of pinnipeds under a variety of physiological and handling conditions. The data show that the Coulter counter hematocrit values were 4%‐15% higher than those measured by microcentrifugation. In addition, blood samples from restrained animals showed consistently elevated hematocrit values relative to resting subjects. A significant difference was also found between hematocrit values from pups and adults. Finally, hematocrit was shown to decline over the course of isofluorane anesthesia. Taken together, these results suggest that laboratory methodology, developmental state, and animal handling techniques can significantly alter hematocrit values in pinnipeds. Thus, modeling efforts that require representative hematocrit values, such as calculations of total blood oxygen stores, can be markedly impacted by variations in hematocrit measurement techniques and sampling regimes.
ASSESSMENT OF HETEROGENEITY IN SIGHTING PROBABILITIES OF HUMPBACK WHALES WITHIN VIEWING RANGE OF CAPE VIDAL, SOUTH AFRICA
Authors: Findlay K. P. , Best P. B. 
Published: August 2006

AbstractThe migrations of humpback whales on the African east coast were monitored between 1988 and 1991 at Cape Vidal, South Africa. Shore‐based surveys of the northward migration were undertaken each winter, and a survey of the southward migration was undertaken in 1990, from an approximately 60‐m‐high vantage point on a headland. Independent‐observer surveys were carried out in both 1990 (22 d) and 1991 (51 d) to determine the proportion of the population within the survey area that were being missed by observers using a single mark‐release model. Results were stratified into three distance intervals from the shore and three sighting condition intervals; there were constant sighting probabilities from the south tower under different sighting conditions, while those from the north tower increased slightly as sighting conditions improved. Sighting probabilities from both towers were highest in the intermediate distance interval and decreased in both the inshore and offshore regions.
ESTIMATES OF THE NUMBERS OF HUMPBACK WHALES OBSERVED MIGRATING PAST CAPE VIDAL, SOUTH AFRICA, 1988–1991
Authors: Findlay K. P. , Best P. B. 
Published: August 2006

AbstractA recovery‐monitoring program of the African east coast humpback whale population was carried out through shore‐based visual surveys from Cape Vidal, northern Natal. Surveys of the northward migration were undertaken each winter from 1988 to 1991, and a survey of the southward migration was undertaken in 1990. Independent observer surveys were undertaken during June 1990 and during the entire 1991 survey. Hourly densities of groups sighted each day were adjusted for groups missed by observers with distance from the shore and under different sighting conditions. Densities were multiplied by 24 h and the mean group size of the survey year to give resulting daily densities of individuals, which were summed to provide totals of whales sighted during each year's survey. The best estimate of population size was 1,711 (made during the northward migration of 1990), although this is likely to be biased downwards by a proportion of the population passing outside of observers’view. Bootstrapping of the 1991 daily data resulted in CVs between 11.4% and 12.2%. The numbers sighted show the population to have undergone considerable recovery since protection in October 1963.
EPIDEMIOLOGY OF POXVIRUS IN SMALL CETACEANS FROM THE EASTERN SOUTH PACIFIC
Authors: Bressem Marie‐Françloise Van , Waerebeek Koen Van 
Published: August 2006

AbstractThe prevalence of‘tattoo’skin lesions, characteristic of poxvirus infection, was examined in 339 small cetaceans captured in gillnet fisheries off coastal Peru: 196 Lagenorhynchus obscurus (34.7%, CI 29.0%–41.8%), 54 Delphinus capensis (61.1%, CI 46.6%–74.1%), 77 Phocoena spinipinnis (62.3%, CI 50.5%–73.2%) and 12 offshore Tursiops truncatus (41.6%, CI 15.2%–72.3%). Sexual variation in tattoo prevalence was significant only in P spinipinnis with males two times more infected than females. Prevalence of poxvirus infection was correlated with the body length class in all species. It peaked around weaning age, supposedly in part due to the loss of maternal protection, and then gradually decreased as immunity developed in the delphinids, but remained high in the porpoise. This pattern is indicative of an endemic infection equivalent to a children's viral disease. The generalized distribution of the tattoos in several animals suggests that viremia may occur. Indications are that the incidence of the disease in L. obscurs and P. spinipinnis may have increased since 1990, however additional research is needed to confirm this trend.
BEHAVIORAL SIGNIFICANCE OF UNDERWATER VOCALIZATIONS OF CAPTIVE LEOPARD SEALS, HYDURGA LEPTONYX
Authors: Rogers T. L. , Cato Douglas H. , Bryden M. M. 
Published: August 2006

AbstractTwo groups of underwater vocalizations were identified in a three‐year study of two captive leopard seals, Hydurga leptonyx (one female and one male at Taronga Zoo, Sydney). This was supplemented by recordings over three months from a male at Marineland, New Zealand. The sexual state of the seals at Taronga was deduced from serum hormonal concentrations: the female was considered to be in estrus at specific times during the breeding season. The seal at Marineland, New Zealand was assumed to be sexually mature on the basis of size and age. Of 12 different underwater sound types recorded, six were produced by the seals at Taronga Zoo during agonistic interactions (local calls) and were heard through most of the year. The other six sound types were produced by lone seals. These broadcast calls were produced by the female only when sexually receptive, and by the mature male during December and January, months believed to be the breeding season of wild leopard seals. We propose that underwater acoustic behavior is important in the mating system of this species, and that broadcast calls are used by mature females to advertise their sexual receptivity, and possibly by mature males in search of mates.
STATUS OF THE PACIFIC WALRUS POPULATION, 1950–19891
Authors: Fay F. H. , Eberhardt L. L. , Kelly B. P. , Burns J. J. , Quakenbush L. T. 
Published: August 2006

AbstractThe 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.