bluuebunny/crossref_metadata_2025_split huggingface dataset:
BEHAVIOR AND ECOLOGY OF THE ATLANTIC WHITE‐SIDED DOLPHIN (LAGENORHYNCHUS ACUTUS) IN COASTAL NEW ENGLAND WATERS
Authors: Weinrich Mason T. , Belt Cynthia R. , Morin David 
Published: August 2006

AbstractAtlantic white‐sided dolphins (Lagenorhynchus acutus) are among the most abundant, and least studied, cetaceans in coastal New England. Between April and October 1984 through 1997 we sighted 1,231 groups of Atlantic white‐sided dolphins, primarily on Stellwagen Bank and Jeffreys Ledge (two shallow glacial deposits along the coasts of Massachusetts, New Hampshire, and Maine). Mean group size was 52 (≥90.9), and was significantly larger from August through October (71.9 ± 111.4) than April through June (35.0 ± 45.4). Calf sightings were uncommon until June and July, after which they were present in over 50% of groups. Combined with observations of apparent newborn calves, this confirms that early summer is an important calving period. The presence of calves did not, however, solely account for the increase in group size. Boat interaction (bow‐ and stern‐wake riding) was the most commonly recorded behavior (47.4% of sightings), followed by traveling (31.4%), interactions with other cetacean species (27.6%), social interaction (15.5%), and feeding (9.5%). While feeding was uncommon, one observation of apparently coordinated “ball” feeding was seen with sand lance (Ammodytesspp.) as the visible prey. Aerial behavior showed a positive correlation with group size, although it was often impossible to tell whether the same dolphins were leaping repeatedly. Eighty‐eight dolphins were photo‐identified using either unusual body pigment or a distinctive dorsal fin. While several individuals were reidentified between years and between areas, no reidentifications were made within a year in the same area. Unusually pigmented individuals were much more likely to be reidentified than those with distinctive dorsal fins, most likely due to higher visibility. We suggest that Atlantic white‐sided dolphins are generally using the study area as transients in what appears to be a large home range.
COASTAL BOTTLENOSE DOLPHINS FROM SOUTHEASTERN AUSTRALIA ARE TURSIOPS ADUNCUS ACCORDING TO SEQUENCES OF THE MITOCHONDRIAL DNA CONTROL REGION
Authors: Möller Luciana M. , Beheregaray Luciano B. 
Published: August 2006

AbstractSequence analysis of the mitochondrial DNA control region was used to clarify the taxonomic status of two coastal bottlenose dolphin populations from southeastern Australia currently classified as Tursiops truncatus. A 368‐bp segment of the control region of 57 biopsy‐sampled, photo‐identified dolphins of Jervis Bay and Port Stephens was compared to published sequences of T. truncatus and T. aduncus from different oceanic regions. Sequence divergence between haplotypes from southeastern Australia and T. aduncus was much lower than that from T. truncatus. Analyses using two different methods of phylogenetic reconstruction unambiguously placed all haplotypes from southeastern Australia in a group composed exclusively of T. aduncus. The results strongly indicated that these two bottlenose dolphin populations belong to T. aduncus, extending the range of the species to subtropical waters of the Western South Pacific Ocean.
GEOGRAPHICAL VARIATION OF THE PARASITE, PHYLLOBOTHRIUM DELPHINI (CESTODA), IN BALL'S PORPOISE, PHOCOENOIDES DALLI, IN THE NORTHERN NORTH PACIFIC, BERING SEA, AND SEA OF OKHOTSK
Authors: Walker William A. 
Published: August 2006

AbstractPrevalence of the larval cestode, Phyllobothrium delphini, was estimated from 2,445 Dall's porpoise, Phocoenoides dalli, from the incidental take of the Japanese high seas salmon drift‐net fishery in the northwestern North Pacific Ocean, Bering Sea, and a local hand harpoon fishery in the southern Sea of Okhotsk. Prevalence of P. delphini was 22.7% in the northwestern North Pacific Ocean and 1.4% in the Bering Sea. This parasite was not found in the southern Sea of Okhotsk. Geographical differences in the prevalence of P. delphini may be due, at least in part, to regional differences in abundance of elasmobranchs known to feed on marine mammals and suspected as hosts of the parasite. Estimated intensity of infection of individual porpoises by P. delphini was low (estimated mean intensity of 3.5 plerocercoids per animal). This is a low intensity of infection compared to other species of small cetaceans studied and may be due to both differences in regional abundance of elasmobranchs and the comparatively short life span of P. dalli.
CORRECTING AERIAL SURVEY COUNTS OF HARBOR SEALS (PHOCA VITULINA RICHARDSI) IN WASHINGTON AND OREGON
Authors: Huber Harriet R. , Jeffries Steven J. , Brown Robin F. , Delong Robert L. , Vanblaricom Glenn 
Published: August 2006

AbstractAerial surveys of harbor seals on land produce only a minimum assessment of the population; a correction factor to account for the missing animals is necessary to estimate total abundance. In 1991 and 1992, VHF radio tags were deployed on harbor seals (n= 124) at six sites in Washington and Oregon. During aerial surveys a correction factor to account for seals in the water was determined from the proportion of radio‐tagged seals on shore during the pupping season. This proportion ranged from 0.54 to 0.74. Among the six sites there was no significant difference in the proportion of animals on shore nor was there a difference in age/sex categories of seals on shore between sites. The pooled correction factor for determining total population abundance was 1.53. An additional 32 seals were radio tagged in 1993 at one of the sites used in 1991. Comparing data from the two years, we found no interannual variation. Aerial surveys of all known harbor seal haul‐out sites in Washington (n= 319) and Oregon (n= 68) were flown during the peak of the pupping season, 1991–1993. The Washington and Oregon harbor seal population was divided into two stocks based on pupping phenology, morphometics, and genetics. Mean counts for the Washington inland stock were 8,710 in 1991, 9,018 in 1992, and 10,092 in 1993. Oregon and Washington coastal stock mean counts were 18,363 in 1991, 18,556 in 1992, and 17,762 in 1993. Multiplying the annual count by the correction factor yielded estimates of harbor seal abundance in the Washington inland stock of 13,326 (95% CI = 11,637–15,259) for 1991, 13,798 (95% CI = 11,980–15,890) for 1992, and 15,440 (95% CI = 13,382–17,814) for 1993. In the Oregon and Washington coastal stock the corrected estimate of harbor seal abundance was 28,094 (95% CI = 24,697–31,960) in 1991, 28,391 (95% CI = 24,847–32,440) for 1992, and 27,175 (95% CI = 23,879–30,926) for 1993.
CHARACTERIZATION OF BEAKED WHALE (ZIPHIIDAE) AND SPERM WHALE (PHYSETER MACROCEPHALUS) SUMMER HABITAT IN SHELF‐EDGE AND DEEPER WATERS OFF THE NORTHEAST U. S.
Authors: Waring G. T. , Hamazaki T. , Sheehan Daniel , Wood Grayson , Baker Sheekela 
Published: August 2006

AbstractSperm whales (Physeter macrocephalus) and beaked whales (Mesoplodonspp. andZiphius cavirostris) are deep‐diving cetaceans that frequent shelf‐edge and Gulf Stream waters off the northeast U. S. coast. Sighting data collected during seven summer (1990, 1991, 1993, and 1995–1998) shipboard surveys were analyzed using a geographic information system to determine habitat use based on bathymetric and oceanographic features. Although sighting rates were lower for beaked whales, both taxa occupied similar habitats. Beaked whales were concentrated at the colder shelf edge, whereas sperm whales were associated with warmer off‐shelf water. Mean sighting rates for both taxa were higher in canyon features, but only beaked whale sighting rates were significantly different between canyon and non‐canyon habitat (Wilcoxon signed rank testP= 0.007). Within the shared habitat, the two taxa were separated at fine‐scale based on oceanographic features.
MORPHOLOGY OF THE EYE AND SURROUNDING STRUCTURES OF THE BOWHEAD WHALE, BALAENA MYSTICETUS
Authors: Zhu Qian , Hillmann Daniel J. , Henk William G. 
Published: August 2006

AbstractObservations were made on eyes from 46 bowhead whales, Balaena mysticetus, taken in the subsistence harvest near Barrow, Point Hope, Savoonga, and Kaktovik, Alaska. Data reported here include palpebral, eyeball, corneal, scleral, pupillary, and lens dimensions. These quantitative data have allowed us to compare structures relative to one another and sometimes to compare them with similar structures in other species. We found, for example, that the cornea is almost three times as thick at its periphery as at its center; that when the ratio of scleral thickness and eyeball size are compared, the ratio, in the bowhead whale, is twice that of any other cetacean for which data were available; and that the corneal and pupillary width to height ratios indicate a less elongated cornea and pupil than has been reported in other cetaceans. We also found a strong correlation between body length and eyeball size indicating that within the species, unlike what is seen between species, larger animals have larger eyes. Novel observations include the presence of three periorbital fatty layers, 112 ciliary processes, the presence of scleral canals, the absence of an obvious fovea or macular region in the retina, a holangiotic pattern of fundic vessels, the presence of zonular fibers and a lens sheath, and the absence of an obvious pupillary operculum. Anatomical features like the wide angle of divergence and the palpebral dimensions suggest the absence of binocular vision while features like the size of the palpebral sac, abundant conjuctival fat, and the prominence of the retractor bulbi muscle suggest mechanisms for the protrusion and retraction of the eyeball.
SEAL RESPONSES TO AIRGUN SOUNDS DURING SUMMER SEISMIC SURVEYS IN THE ALASKAN BEAUFORT SEA
Authors: Harris Ross E. , Miller Gary W. , Richardson W. John 
Published: August 2006

AbstractNumbers, sighting distances, and behavior of seals were studied during a nearshore seismic program off northern Alaska in July‐September 1996. We observed from the seismic vessel for 885.6 h, including all periods (day and night) when airguns operated and many periods without airguns. Of 422 seals seen, 421 were seen in daylight; 91‐8% were ringed seals, 7.3% were bearded seals, and 0.9% were spotted seals. About 79% were first seen within 250 m of the seismic boat, and sighting rate declined rapidly at lateral distances > 50 m. During daylight, seals were seen at nearly identical rates (0.60‐0.63/ h) during periods with no airguns firing, one airgun, and a “full‐array” of 8‐11 120‐in3 airguns. However, seals tended to be farther away (P < 0.0001) during full‐array seismic. There was partial avoidance of the zone <150 m from the boat during full‐array seismic, but seals apparently did not move much beyond 250 m. “Swimming away” was more common during full‐array than no‐airgun periods, but relative frequencies of five behaviors did not differ significantly among distance categories. Airgun operations were interrupted 112 times when seals were sighted within safety radii (150–250 m). The National Marine Fisheries Service specified these radii in the Incidental Harassment Authorization issued for the project; they are based on a 190 dB re 1 μPa (rms) criterion for broadband received level. Methods for estimating numbers of seals potentially affected by the seismic program are described, and effectiveness of monitoring and mitigation is discussed. There is an urgent need for more data on effects of strong seismic pulses on seals.
ONTOGENETIC AND SEASONAL VARIATION IN BLOOD PARAMETERS IN SOUTHERN ELEPHANT SEALS
Authors: Lewis Mirtha , Campagna Claudio , Uhart Marcela , Ortiz Charles Leo 
Published: August 2006

AbstractBlood samples were collected from 156 free‐ranging southern elephant seals (Mirounga leonina) from Peninsula Valdes to study the variation in blood parameters related to ontogeny and the annual cycle. Samples ranged from newborn pups to adults. Interactions between age and sex showed different trends in ontogenetic changes of blood parameters (MANOVA, Wilkis' Lamb‐da12,243= 0.75,P< 0.01). The hematocrit (HCT) and hemoglobin concentration (HB) reached adult levels early in life. Weanlings had 14 % higher HCT than pups, and similar levels to juveniles and adults (HCT range = 46%‐62 %). HB of males were below those of females from weaning (18.4vs. 20.3 g/dl) to adulthood (19.8vs. 22.3 g/dl). Red blood cell counts (RBC) did not change significantly from pups to juveniles (2.8–3.2 106/μl), but varied for adults at different times of the annual cycle. Breeding females had higher RBC than molting females (3.1vs.2.4 106/μl). Changes in blood parameters are related to the development of diving capabilities from pups to juveniles. Changes in adults were associated with different stages of the annual cycle, and these may be the result of the requirements imposed by pregnancy and fasting duration.
DIET OF RINGED SEALS (PHOCA HISPIDA) ON THE EAST AND WEST SIDES OF THE NORTH WATER POLYNYA, NORTHERN BAFFIN BAY
Authors: Holst Meike , Stirling Ian , Hobson Keith A. 
Published: August 2006

AbstractIn conjunction with the International North Water Polynya Study (NOW) in northern Baffin Bay, we examined the diets of ringed seals (Phoca hispida)1on the west (Grise Fiord, Nunavut) and east (Qaanaaq, Greenland) sides of the polynya, using conventional stomach content analysis, as well as inferences from stable isotope ratios in seal muscle. Between May and July 1998, stomach and muscle tissue samples were collected from 99 ringed seals taken near Grise Fiord and 100 taken near Qaanaaq. The amphipodThemisto libellulawas the dominant prey type in the diet of immature ringed seals from Grise Fiord, whereas arctic cod (Boreogadus saida) and polar cod (Arctogadus glacialis) predominated in the diet of adults. Both immature and adult seals collected near Qaanaaq fed predominantly on arctic cod. Overall, seals collected near Grise Fiord had significantly higher δ13C values than those collected near Qaanaaq (P< 0.001), but there was no statistical separation in δ15N values between the two samples (P= 0.06). Differences in diets of ringed seals from the east and west sides of the North Water Polynya may be due to differences in prey distribution and/or differences in biological productivity and fish biomass within the polynya.
A RESIDENT POPULATION OF INDO‐PACIFIC BOTTLENOSE DOLPHINS (TURSIOPS ADUNCUS) IN AMAKUSA, WESTERN KYUSHU, JAPAN
Authors: Shirakihara Miki , Shirakihara Kunio , Tomonaga Jyunji , Takatsuki Megumi 
Published: August 2006

AbstractResidency patterns and population size were examined for Indo‐Pacific bottlenose dolphins (Tursiops aduncus) in the coastal waters of Amakusa‐Shimoshima Island, western Kyushu, Japan, from summer 1994 to fall 1998. A total of 203 individuals were identified. The number of newly identified individuals barely increased after the first 1.5 yr. The identified individuals in one season were frequently resighted with percentages of mostly over 60% during the subsequent seasons. Most of the dolphins off Amakusa were yearround residents, although the total range of their habitat was unknown. The population size estimated by the mark‐recapture technique was 218 individuals with a CV of 5.41% in 1995–1997. The group commonly consisted of more than 100 individuals. The large group size was thought to be a response to feeding on schooling fishes.
GRAY WHALE CALF PRODUCTION 1994–2000: ARE OBSERVED FLUCTUATIONS RELATED TO CHANGES IN SEASONAL ICE COVER?
Authors: Perryman Wayne L. , Donahue Meghan A. , Perkins Peter C. , Reilly Stephen B. 
Published: August 2006

AbstractWe conducted shore‐based sighting surveys to estimate the number of northbound migrating gray whale calves passing Piedras Blancas, California, for seven consecutive years (1994–2000). In addition, we conducted aerial surveys to determine offshore distribution of the migration in 1994 and 1995, measured day/night migration rates with thermal sensors in 1994–1996, and maintained concurrent replicate watches near the peak of each migration to estimate the proportion of the cow/calf pairs missed by the standard watch team. During good weather, we counted 325, 194, 407, 501, 440, 141, and 96 calves during 1994–2000, respectively. Correcting these counts for periods not on watch and for calves missed, produced final estimates of 945 calves (SE = 68.21) for 1994, 619 calves (SE = 67.19) for 1995, 1,146 calves (SE = 70.67) for 1996, 1,431 calves (SE = 82.02) for 1997, 1,388 calves (SE = 91.84) for 1998, 427 calves (SE = 41.10) for 1999, and 279 calves (SE = 34.79) for 2000. Calf production indices (calf estimate/total population estimate) are 4.2%, 2.7%, 4.8%, 5.8%, 5.5%, 1.7%, and 1.1% for the years 1994–2000, respectively. Fluctuations in calf production over this time period were positively correlated with the length of time that primary feeding habitat was free of seasonal ice during the previous year.
DIET‐TISSUE FRACTIONATION OF STABLE CARBON AND NITROGEN ISOTOPES IN PHOCID SEALS
Authors: Lesage VÉRONIQUE , Hammill Mike O. , Kovacs Kit M. 
Published: August 2006

AbstractDiet‐tissue isotopic fractionation of carbon (C) and nitrogen (N) isotopes in short‐ and longer‐term diet integrators of diet (i. e., blood serum and red cells), that involve non‐invasive sampling techniques was examined using three species of phocid seals (harbor seals, gray seals, and harp seals) fed a known diet. Variability in diet‐tissue fractionation values within and between species was also scrutinized to determine the legitimacy of using values obtained from one species to explore trophic positions and diets of other related species. All captive seals raised on a constant diet had tissues enriched in 13C and 15N relative to their diet. Diet‐tissue isotopic fractionation values were generally consistent among conspecifics and among phocid species for a given tissue. Trophic isotopic enrichment in 13C was significantly higher in red blood cells (+1.5%±) than in blood serum (+0.8%±), whereas the reverse was observed for nitrogen isotopes (+1.7%± in red cells vs. +3.1%± in serum). However, 13C‐depleted lipids were not extracted from blood tissues in this study. This results in a downward bias in the diet‐tissue fractionation factors for carbon for both red cells and blood serum, particularly the latter because of their significantly higher lipid contents (x̄± SD = 14.6 ± 2.3%; n= 20; red blood cells 3.8 ± 0.9%±; n= 50, muscle 7.7 ± 2.0; n= 21) in marine mammals.
HAUL‐OUT SELECTION BY PACIFIC HARBOR SEALS (PHOCA VITULINA RICHARDII): ISOLATION AND PERCEIVED PREDATION RISK
Authors: Nordstrom Chad A. 
Published: August 2006

AbstractThe potential for non‐aquatic predators to influence habitat use by harbor seals (Phoca vitulina) in a nearshore marine environment was studied by examining haul‐out site use and through an experimental approach. Distance from shore, distance to possible foraging depths, peripheral water depth, and haul‐out areas were quantified for each haul‐out. There was a positive relationship between the number of seals hauled out and the distance from shore for eight known haul‐out sites. The hypothesis that harbor seals increasingly hauled out farther offshore to reduce predation risk was tested experimentally by measuring their response to a model of a potential terrestrial predator in comparison to a control object, and to disturbance by a human at one of the study sites. Harbor seals abandoned the haul‐out in the presence of the predator model, but showed little response to the controls, suggesting they possess a threat image for terrestrial predators and avoid hauling out when it is perceived. These results support the hypothesis that harbor seals select isolated sites to reduce exposure to terrestrial carnivores.
AIRCRAFT SOUND AND DISTURBANCE TO BOWHEAD AND BELUGA WHALES DURING SPRING MIGRATION IN THE ALASKAN BEAUFORT SEA
Authors: Patenaude Nathalie J. , Richardson W. John , Smultea Mari A. , Koski William R. , Miller Gary W. , Würsig Bernd , GReene Charles R. 
Published: August 2006

AbstractShort‐term behavioral responses of bowhead whales (Balaena mysticetus) and beluga whales (Delphinapterus leucas) to a Bell 212 helicopter and Twin Otter fixed‐wing aircraft were observed opportunistically during four spring seasons (1989–1991 and 1994). Behaviors classified as reactions consisted of short surfacings, immediate dives or turns, changes in behavior state, vigorous swimming, and breaching.The helicopter elicited fewer detectable responses by bowheads (14% of 63 groups) than by belugas (38% of 40). Most observed reactions by bowheads (63%) and belugas (86%) occurred when the helicopter was at altitudes ≤150 m and lateral distances ≤250 m. Belugas reacted significantly more frequently during overflights at lateral distances ≤250 m than at longer lateral distances (P= 0.004). When the helicopter was on the ice with engines running, 7 of 14 groups of belugas reacted, up to 320 m away, sometimes with small‐scale (≤100 m) diversion; only 1 of 8 groups of bowheads reacted.For the fixed‐wing aircraft, few bowheads (2.2%) or belugas (3.2%) were observed to react to overflights at altitudes 60–460 m. Most observed reactions by bowheads (73%) and belugas (70%) occurred when the fixed‐wing aircraft was at altitudes ≤182 m and lateral distances ≤250 m. However, the proportions reacting, especially to low‐altitude flights (e. g., ≤182 m), were underestimated for both species because observation opportunities were brief. Even so, reactions were more common when the aircraft was low (≤182 m): P= 0.009 for belugas, P= 0.06 for bowheads. There was little if any reaction by bowheads when the aircraft circled at altitude 460 m and radius 1 km.Aircraft sounds measured underwater at depths 3 m and 18 m showed that a Bell 212 helicopter was 7–17.5 dB noisier than a Twin Otter (10–500 Hz band). Bell 212 sound consisted mainly of main rotor tones ahead of the helicopter and tail rotor tones behind it. Twin Otter sound contained fewer prominent tones. Peak sound level as received underwater was inversely related to aircraft altitude, and received levels at 3 m depth averaged 2.5 dB higher than at 18 m depth. The dominant low‐frequency components of aircraft sound are presumed to be readily audible to bowheads. For belugas, these components may be inaudible, or at most only weakly audible. Mid‐frequency sound components, visual cues, or both, are probably important in eliciting beluga reactions to aircraft.
BEHAVIORAL EVIDENCE OF THERMAL STRESS FROM OVERHEATING IN UK BREEDING GRAY SEALS
Authors: Twiss S. D. , Wright N. C. , Dunstone N. , Redman P. , Moss S. , Pomeroy P. P. 
Published: August 2006

AbstractGray seals (Halichoerus grypus) in the UK exhibit clear preferences for pupping close to pools of water on inland breeding sites. The reasons for this are unclear as seals are thought to derive all their water requirements from the metabolism of fat. Likewise, the prospect of seals overheating during the UK's cool, damp, autumnal breeding seasons, has seemed unlikely, but has not been previously explored. Here, we provide preliminary behavioral evidence of thermal stress in female gray seals breeding on the island of North Rona, Scotland. Video footage provided measures of proximity to, and the proportion of animals bathing in, pools in relation to meteorological data (temperature, mean sea‐level pressure, rainfall, wind speed and direction) on four dates spread through a single breeding season. The proportion of females close to pools increased with pressure (warmer, drier conditions) and decreased on wetter days. In addition, analyses of colony‐wide patterns of seal dispersion showed that females tended to be closer to pools of water at higher pressures and temperatures and at lower wind‐speeds. These results provide the first evidence of thermal stress and behavioral thermoregulation through access to pools of water in a phocid breeding in temperate autumnal conditions.