bluuebunny/crossref_metadata_2025_split huggingface dataset:
ABUNDANCE OF BLUE AND HUMPBACK WHALES IN THE EASTERN NORTH PACIFIC ESTIMATED BY CAPTURE‐RECAPTURE AND LINE‐TRANSECT METHODS
Authors: Calambokidis John , Barlow Jay 
Published: August 2006

AbstractWe estimated humpback and blue whale abundance from 1991 to 1997 off the west coast of the U. S. and Mexico comparing capture‐recapture models based on photographically identified animals and line‐transect methods from ship‐based surveys. During photo‐identification research we obtained 4,212 identifications of 824 humpback whales and 2,403 identifications of 908 blue whales primarily through non‐systematic small‐boat surveys along the coast of California, Oregon, and Washington. Line‐transect surveys from NOAA ships in 1991, 1993, and 1996 covered approximately 39,000 km along the coast of Baja California, California, Oregon, and Washington out to 555 km from shore. The nearshore and clumped distribution of humpback whales allowed photographic identification from small boats to cost‐effectively sample a substantial portion of the population, but made it difficult to obtain effective samples in the line‐transect surveys covering broad areas. The humpback capture‐recapture estimates indicated humpback whale abundance increased over the six years (from 569 to 837). The broader more offshore distribution of blue whales made it harder to obtain a representative sample of identification photographs, but was well suited to the line‐transect estimates. The line‐transect estimates, after correction for missed animals, indicated approximately 3,000 blue whales (CV = 0.14). Capture‐recapture estimates of blue whales were lower than this: approximately 2,000 when using photographs obtained from the line‐transect surveys as one of the samples. Comparison of the results from the two methods provides validation, as well as insight into potential biases associated with each method.
GEOGRAPHIC GENETIC STRUCTURE IN THE FRANCISCANA DOLPHIN (PONTOPORIA BLAINVILLEI)
Authors: Lázaro Marila , Lessa Enrique P. , Hamilton Healy 
Published: August 2006

AbstractThe franciscana, Pontoporia blainvillei, is endemic to the South Atlantic coast of South America. The species is of conservation concern because it suffers elevated mortality rates due to incidental captures in fishing nets, and perhaps it is one of the most threatened small cetaceans in this region. Previous morphological and genetic studies have suggested the existence of at least two distinct stocks to the north and south of Santa Catarina Island in Brazil. Fixed differences were found between a sample from Rio de Janeiro and one from Rio Grande do Sul, in southern Brazil. Using 94 sequences of the control region of mitochondrial DNA, we examined the genetic structure of the species. We found no shared haplotypes between Rio de Janeiro and samples from the southern range of the species distribution. However, a phylogenetic analysis suggests that the former population is diphyletic with respect to the southern samples. This suggests that the populations have not been isolated long enough to reach reciprocal monophyly. Furthermore, genetic differentiation is broadly consistent with a simple model of isolation by distance, that therefore appears as an alternative to a model of strict isolation of two stocks. The estimated levels of gene flow are higher among neighboring populations, and decrease as more distant localities are compared. Finally, the molecular data suggest that franciscanas have expanded in Rio de Janeiro.
MAJOR HISTOCOMPATIBILITY COMPLEX I POLYMORPHISM IN A CETACEAN: THE GRAY WHALE (ESCHRICHTIUS ROBUSTUS)
Authors: Flores‐Ramirez Sergio , Miller Robert D. , Urban‐Ramirez Jorge 
Published: August 2006

AbstractVertebrate Major Histocompatibility Complex‐I (Mbc‐I) proteins bind and display self and foreign peptides on the cell surface. Mbc‐I polymorphism is considered critical for eliciting immune responses to a diversity of antigens, and thus, for the health and conservation of a species. Based on restriction fragment length polymorphism it was concluded that whales generally have low Mbc‐I polymorphism. This was attributed to the weak pathogenic pressure in aquatic habitats. Since gray whales' habits might favor their encounter with diverse pathogens, resulting in selection pressures for Mbc variability, we searched for functional polymorphism of gray whale's Mbc‐I exon 2 sequences that encode the α‐1 protein domain of the antigen‐binding region. We sequenced twelve Mbc‐I exon 2 clones from each of seven gray whales. Most obtained sequences were similar to functional artiodactyl sequences, and their reconstructed phylogeny consistently showed three whale Mbc‐I exon 2 sequence clusters (A, B, and C). Sequences within a given cluster and from distinct clusters, showed a greater number of non‐synonymous than synonymous substitutions, that commonly shifted the physiochemical properties of the involved residue, suggesting the existence of a diverse repertoire of Mbc‐I antigen recognition sites in gray whales, and that selection maintains gray whale's Mbc‐I allelic diversity.
DETERMINING BLUBBER FATTY ACID COMPOSITION: A COMPARISON OF IN SITU DIRECT AND TRADITIONAL METHODS
Authors: Thiemann Gregory W. , Budge Suzanne M. , Iverson Sara J. 
Published: August 2006

AbstractFatty acids (FAs) are used to make inferences about the foraging behavior and diets of free‐ranging marine mammals. However, several methods are currently available for determining the FA composition of blubber and these methods may produce different results. We compared in situ direct transesterification methods, where a small amount of tissue is sampled, with more traditional methods involving prior lipid extraction of the entire sample of interest. Using gray seal (Halichoerus grypus) and beluga whale (Delphinapterus leucas) blubber, we found that when the direct in situ method was used on a 2‐mg sample of blubber, the resulting FA profile differed significantly from that produced when traditional full‐extraction methods were employed. Regardless of where the small spot sample was taken within the blubber depth, it was not representative of the entire blubber FA composition, as blubber is non‐homogeneous throughout its depth. We also modified the in situ direct method to allow analysis of the entire blubber layer. Results of this full‐layer direct method compared quite favorably with traditional extraction methods and may provide a reasonable alternative for analyses. Although application of our full‐layer direct method will require further verification in certain marine mammal blubber samples, we conclude that the large differences obtained when using the direct method are not a consequence of the chemical method itself. Rather, they arise from non‐representative sampling of the blubber FA composition.
A STAGE‐BASED MODEL OF MANATEE POPULATION DYNAMICS
Authors: Runge Michael C. , Langtimm Catherine A. , Kendall William L. 
Published: August 2006

AbstractA stage‐structured population model for the Florida manatee (Trichechus manatus latirostris) was developed that explicitly incorporates uncertainty in parameter estimates. The growth rates calculated with this model reflect the status of the regional populations over the most recent 10‐yr period. The Northwest and Upper St. Johns River regions have growth rates (λ) of 1.037 (95% interval, 1.016–1.056) and 1.062 (1.037–1.081), respectively. The Southwest region has a growth rate of 0.989 (0.946–1.024), suggesting this population has been declining at about 1.1% per year. The estimated growth rate in the Atlantic region is 1.010 (0.988–1.029), but there is some uncertainty about whether adult survival rates have been constant over the last 10 yr; using the mean survival rates from the most recent 5‐yr period, the estimated growth rate in this region is 0.970 (0.938–0.998). Elasticity analysis indicates that the most effective management actions should seek to increase adult survival rates. Decomposition of the uncertainty in the growth rates indicates that uncertainty about population status can best be reduced through increased monitoring of adult survival rate.
METHODS FOR JOINT INFERENCE FROM MULTIPLE DATA SOURCES FOR IMPROVED ESTIMATES OF POPULATION SIZE AND SURVIVAL RATES
Authors: Goodman Daniel 
Published: August 2006

AbstractCritical conservation decisions often hinge on estimates of population size, population growth rate, and survival rates, but as a practical matter it is difficult to obtain enough data to provide precise estimates. Here we discuss Bayesian methods for simultaneously drawing on the information content from multiple sorts of data to get as much precision as possible for the estimates. The basic idea is that an underlying population model can connect the various sorts of observations, so this can be elaborated into a joint likelihood function for joint estimation of the respective parameters. The potential for improved estimates derives from the potentially greater effective sample size of the aggregate of data, even though some of the data types may only bear directly on a subset of the parameters. The achieved improvement depends on specifics of the interactions among parameters in the underlying model, and on the actual content of the data. Assuming the respective data sets are unbiased, notwithstanding the fact that they may be noisy, we may gauge the average improvement in the estimates of the parameters of interest from the reduction, if any, in the standard deviations of their posterior marginal distributions. Prospective designs may be evaluated from analysis of simulated data. Here this approach is illustrated with an assessment of the potential value in various ways of merging mark‐resight and carcass‐survey data for the Florida manatee, as could be made possible by various modifications in the data collection protocols in both programs.
HIGH PERFORMANCE TURNING CAPABILITIES DURING FORAGING BY BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS)
Authors: Maresh Jennifer L. , Fish Frank E. , Nowacek Douglas P. , Nowacek Stephanie M. , Wells Randall S. 
Published: August 2006

AbstractLarge predators should have difficulty catching small prey because small animals demonstrate greater maneuverability and agility compared to large animals. The ability of a predator to capture small prey indicates locomotor strategies to compensate for inequities in maneuverability. Bottlenose dolphins (Tursiops truncatus) in Sarasota Bay, Florida feed on fish at least one order of magnitude smaller than themselves. To examine the locomotor strategies involved in prey capture, the foraging movements of these dolphins were videotaped from overhead using a remotely‐controlled camera suspended from a helium‐filled aerostat, which was tethered to an observation vessel. Dolphins were observed to rapidly maneuver during chases of fish in open water or around patches of rooted vegetation. Video analysis of the chase sequences indicated that the dolphins could move the rostrum through small radius turns with a mean value of 0.20 body lengths and with a minimum value of 0.08 body lengths. Mean rate of turn was 561.6°/sec with a maximum rate measured at 1,372.0°/sec. High turning rates with small turning radii were primarily the result of maneuvers in which the dolphin rolled 90° and rapidly flexed its body ventrally. The ability of dolphins to change body orientation in multiple rotational axes provides a mechanism to reduce turning radius and increase turning rate to catch small, elusive prey.
RETROSPECTIVE ISOTOPIC ANALYSES OF STELLER SEA LION TOOTH ANNULI AND SEABIRD FEATHERS: A CROSS‐TAXA APPROACH TO INVESTIGATING REGIME AND DIETARY SHIFTS IN THE GULF OF ALASKA
Authors: Hobson Keith A. , Sinclair Elizabeth H. , York Anne E. , Thomason James R. , Merrick Richard E. 
Published: August 2006

AbstractStable isotope (δ15N and δ13C) values of individual tooth annuli of female Steller sea lions (n= 120) collected from the 1960s through the 1980s were used for retrospective analyses of temporal changes in food webs in the Gulf of Alaska and North Pacific Ocean. We also examined isotopically contour feathers of tufted puffins (n= 135) and crested auklets (n= 37) through this period to test for broader isotopic patterns indicative of whole food web changes. Steller sea lions decreased slightly in δ13C and increased in δ15N values, suggesting an increasing trophic level and change in foraging location or oceanographic isotopic signature. Steller sea lion first and second tooth annuli were enriched in 15N and depleted in 13C compared with subsequent annuli, indicating the effects of maternal influence through weaning. The general pattern of increasing δ15N values among Steller sea lions supports previous conclusions regarding a reduction or redistribution of forage fishes and an increase of demersal and semi‐demersal species in the North Pacific ecosystem. There were no significant changes in δ15N values for either bird species. However, δ13C values in both bird species again suggested changes in foraging location or a shift in oceanographic currents.
AQUATIC MATING STRATEGIES OF THE MALE PACIFIC HARBOR SEAL (PHOCA VITULINA RICHARDII): ARE MALES DEFENDING THE HOTSPOT?
Authors: Hayes Sean A. , Costa Daniel P. , Harvey James T. , le Boeuf BURNEY J. 
Published: August 2006

AbstractCompared to the harem and resource defense systems of terrestrial mating pinnipeds, males of aquatic mating species appear unable to monopolize females or resources. We investigated movements, acoustics, and aquatic territorial behavior of male harbor seals, Phoca vitulina richardii, in Elkhorn Slough, California, using VHF telemetry, hydrophones, and acoustic playback experiments. During the mating season 22 males increased time spent in the water and away from haul‐out locations, exhibiting activity patterns similar to Atlantic subspecies. Two acoustic display patterns were observed. At one location multiple males aggregated to display with acoustic activity peaking one month before peak estrus. At two other locations, lone males displayed primarily during peak estrus. Acoustic display areas were non‐adjacent with a mean ± SE size of 4,228 ± 576 m2, similar to harbor seal display patterns in the Moray Firth, Scotland. Underwater playbacks of male vocalizations were used to define territorial boundaries by inducing responses from territory‐holding males. Four solitary males defended adjacent territories (mean area 39,571 ± 18,818 m2) along a travel corridor, similar to observations of harbor seals at Miquelon, Newfoundland. Acoustic display stations appeared to be subcomponents of larger territories. Males exhibited site fidelity to territories for at least 2–4 yr. Females moved through territories freely. The establishment of male‐display territories along female‐traffic corridors resembles terrestrial systems described as hotspot leks.
TEMPORARY THRESHOLD SHIFTS AFTER NOISE EXPOSURE IN THE BOTTLENOSE DOLPHIN (TURSIOPS TRUNCATUS) MEASURED USING EVOKED AUDITORY POTENTIALS
Authors: Nachtigall Paul E. , Supin Alexander Ya. , Pawloski Jeffrey , Au Whitlow W. L. 
Published: August 2006

AbstractThe time course of recovery from temporary threshold shift (TTS) was measured in a bottlenose dolphin, Tursiops truncatus, using an evoked‐potential procedure. The envelope‐following response (EFR), which is a rhythmic train of auditory brainstem responses (ABR) to sinusoidally amplitude‐modulated tones, was used as an indicator of the sound reception by the animal. Variation of the intensity of the stimulus allowed us to measure the animal's hearing via EFR thresholds. During each session, following an initial measure of threshold, the trained animal voluntary positioned itself within a hoop 1 m underwater while a 160 dB re 1 μPa noise of a 4–11 kHz bandwidth was presented for 30 min. After the noise exposure, thresholds were measured again at delays of 5, 10, 15, 25, 45, and 105 min. Measurements were made at test frequencies of 8, 11.2, 16, 22.5, and 32 kHz. The maximum TTS occurred 5 min after exposure and rapidly recovered with a rate of around 1.5 dB per doubling of time. TTS occurred at test frequencies from 8 to 16 kHz, with the maximum at 16 kHz. TTS was negligible at 22.5 kHz and absent at 32 kHz.
HISTORICAL OBSERVATIONS OF HUMPBACK AND BLUE WHALES IN THE NORTH ATLANTIC OCEAN: CLUES TO MIGRATORY ROUTES AND POSSIBLY ADDITIONAL FEEDING GROUNDS
Authors: Reeves Randall R. , Smith Tim D. , Josephson Elizabeth A. , Clapham Phillip J. , Woolmer Gillian 
Published: August 2006

AbstractThe seasonal distributions of humpback and blue whales (Megaptera novaeangliaeandBalaenoptera musculus, respectively) in the North Atlantic Ocean are not fully understood. Although humpbacks have been studied intensively in nearshore or coastal feeding and breeding areas, their migratory movements between these areas have been largely inferred. Blue whales have only been studied intensively along the north shore of the Gulf of St. Lawrence, and their seasonal occurrence and movements elsewhere in the North Atlantic are poorly known. We investigated the historical seasonal distributions of these two species using sighting and catch data extracted from American 18th and 19th century whaling logbooks. These data suggest that humpback whales migrated seasonally from low‐latitude calving/ breeding grounds over a protracted period, and that some of them traveled far offshore rather than following coastal routes. Also, at least some humpbacks apparently fed early in the summer west of the Mid‐Atlantic Ridge, well south of their known present‐day feeding grounds. In assessing the present status of the North Atlantic humpback population, it will be important to determine whether such offshore feeding does in fact occur. Blue whales were present across the southern half of the North Atlantic during the autumn and winter months, and farther north in spring and summer, but we had too few data points to support inferences about these whales' migratory timing and routes.
ABUNDANCE OF CETACEANS IN THE OCEANIC NORTHERN GULF OF MEXICO, 1996–2001
Authors: Mullin Keith D. , Fulling Gregory L. 
Published: August 2006

AbstractThe Gulf of Mexico is a subtropical marginal sea of the western North Atlantic Ocean with a diverse cetacean community. Ship‐based, line‐transect abundance surveys were conducted in oceanic waters (>200 m deep) of the northern Gulf within U. S. waters (380,432 km2) during spring from 1996 to 1997 and from 1999 to 2001. Data from these five surveys were pooled and minimum abundance estimates were based on 12,162 km of effort and 512 sightings of at least 19 species. The most commonly sighted species (number of groups) were pantropical spotted dolphin,Stenella attenuata(164); sperm whale,Physeter macrocephalus(67); dwarf/pygmy sperm whale,Kogia simalbreviceps(58); Risso's dolphin,Grampus griseus(38); and bottlenose dolphin,Tursiops truncatus(24). The most abundant species (number of individuals; coefficient of variation) wereS. attenuata(91,321; 0.16); Clymene dolphin,S. clymene(17,355; 0.65); spinner dolphin,S. longirostris(11,971; 0.71); and striped dolphin,S. coeruleoalba(6,505; 0.43). The only large whales sighted wereP. macrocephalus(1,349; 0.23) and Bryde's whale,Balaenopteraedeni(40; 0.61). Abundances for other species or genera ranged from 95 to 2,388 animals. Cetaceans were sighted throughout the oceanic northern Gulf and, whereas many species were widely distributed, some had more regional distributions.
CHANGES IN HEART RATE VARIABILITY DURING DIVING IN YOUNG HARBOR SEALS, PHOCA VITULINA
Authors: Greaves Danielle K. , Hughson Richard L. , Topor Zbigniew , Schreer Jason F. , Burns Jennifer M. , Hammill Michael O. 
Published: August 2006

AbstractWe studied changes in the patterns of heart rate variability (HRV) that coincide with the development of diving skills in harbor seal pups, Phoca vitulina. Heart rate measurements were collected remotely. Spectral analysis of HRV revealed power within a mid‐frequency band (0.1–0.3 Hz) which was prominent, especially in pups less than 10 d of age. In these younger pups, the heart rate switched cyclically between a low and a high diving heart rate every 3–10 sec. Older pups exhibited a highly controlled diving bradycardia with a lower median and a lower variance when compared to younger individuals. These results provide new insight into the maturation of the bradycardia component of the dive response in harbor seal pups.
BILATERAL DIRECTIONAL ASYMMETRY OF THE APPENDICULAR SKELETON OF THE HARBOR PORPOISE (PHOCOENA PHOCOENA)
Authors: Galatius Anders , Jespersen ÅSe 
Published: August 2006

AbstractDirectional asymmetry (DA) of the lengths, diameters, and masses of the scapula, humerus, radius, and ulna were analyzed on a sample of 213 harbor porpoises from Denmark and West Greenland. The levels of DA were consistent across yearlings and older animals, mature and immature animals, sexes, and populations. All investigated variables showed significant DA favoring the right side. For the pooled sample, DA of lengths ranged from 0.2% SE 0.1 (ulna) to 1.2% SE 0.1 (scapula). DAs of diameters were 1.5% SE 0.2 for the humerus, 0.6% SE 0.1 for the radius, and 1.3% SE 0.2 for the ulna. DA of mass ranged from 2.8% SE 0.5 (humerus) to 4.3% SE 0.7 (ulna). The humerus and ulna had significantly larger mean diameter/ length ratios on the right side than the left, making them more robust. The large DA of scapula length indicates larger muscle mass associated with the right flipper, while the generally more robust right humerii and ulnae may be designed for higher levels of mechanical stress. These DAs and the examples of lateralized behavior recorded in cetaceans, point to the existence of lateralized use of the flippers at the population level in harbor porpoises and possibly other cetacean species.
VERTEBRAL OSTEOLOGY AND COMPLEXITY INLAGENORHYNCHUS ACUTUS(DELPHINIDAE) WITH COMPARISON TO OTHER DELPHINOID GENERA
Authors: Buchholtz Emily A. , Wolkovich Elizabeth M. , Cleary Richard J. 
Published: August 2006

AbstractThe vertebral column of the Atlantic white‐sided dolphin,Lagenorhynchus acutus, reflects the radical reorganization of the cetacean column for locomotion in water. Both posterior thoracic and anterior caudal vertebrae have been “lumbarized,” and discontinuities occur within the caudal series at the synclinal point and fluke base. Morphology changes subtly as body size increases. Neural process height increases more rapidly, and centrum length more variably, than other vertebral parameters. As a result, large animals have disproportionately tall neural processes, short necks, long mid‐body regions, and short flukes. Vertebral columns of large animals also show greater complexity (range, irregularity, and polarization) of centrum length than do those of smaller animals. Comparisons among dolphins reveal that complexity trends with respect to differentiation of parts run counter to the trend with respect to number of parts, a relationship predicted by Williston in 1914.