bluuebunny/crossref_metadata_2025_split huggingface dataset:
REPRODUCTIVE MATURITY AND SEASONALITY OF MALE SPOTTED DOLPHINS, STENELLA ATTENUATA, IN THE EASTERN TROPICAL PACIFIC
Authors: Hohn Aleta A. , Chivers Susan J. , Barlow Jay 
Published: August 2006

AbstractWe estimated age at attainment of sexual maturity and examined reproductive seasonality for male spotted dolphins, Stenella attenuata, from the eastern tropical Pacific Ocean. Maturity was determined by histological examination of testes. Average age at sexual maturation was 14.7 yr (the mean of two readers' age estimates). Testis and epididymis weight and seminiferous tubule diameters were reliable indicators of maturity, whereas age, length and color phase were less reliable. Seasonality was determined by changes in testis and epididymis weight, relative quantity of spermatids and spermatozoa, and lumen diameter, as well as an index of testis development (weight of the right testis and epididymis divided by length of the right testis). Testis and epididymis weights and index values peaked in July and August, midway between two predicted mating seasons for the northern offshore stock, but spermatozoa levels were elevated during the predicted breeding seasons.
AXIAL MUSCULATURE IN THE DOLPHIN (TURSIOPS TRUNCATUS): SOME ARCHITECTURAL AND HISTOCHEMICAL CHARACTERISTICS
Authors: Bello M. A. , Roy R. R. , Martin T. P. , Goforth H. W. , Edgerton V. R. 
Published: August 2006

AbstractIn view of the supposition that a dolphin can swim faster than would be predicted based on its physical features and presumed muscle power potential, studies were initiated to reevaluate the assumptions made in reaching these conclusions. Several previous studies have shown that the architectural and histochemical properties of a skeletal muscle dictate its force, velocity and displacement properties. This study examined the muscle fiber lengths and tendon arrangements of the dorsal and ventral axial muscles in dolphins (Tursiops truncatus). Fiber type and fiber size distributions were determined to reflect the general biochemical characteristics of the musculature. The dorsal muscles had a higher mean fiber length (167 Vs. 90 mm) and the range within and across different dorsal muscles was less (141–199 vs. 37–185 mm) than in the ventral muscles. Both the dorsal and ventral muscles consisted of an overall mean of 50 percent slow twitch and 50 percent fast twitch fiber types. The fast twitch fibers were 67 percent larger (2,200 vs. 1,317 μm2) than the slow twitch fibers in the ventral and 38 percent larger (1,213 Vs. 879 μm2) in the dorsal muscles. In addition, the mean cross sectional area of the fibers in the ventral muscles was approximately 65 percent greater (1,750 vs. 1,072 μm2) than those in the dorsal muscles. The shorter, larger‐diameter fibers of the ventral musculature give it a greater potential for force production for a given amount of muscle mass. In contrast, the dorsal muscles appear to be designed to optimize velocity and displacement, (i.e., longer fibers). These findings contribute to the information necessary for the determination of the power potential of the musculature of the dolphin.
A MASS STRANDING OF SPERM WHALES IN OREGON: SEX AND AGE COMPOSITION OF THE SCHOOL
Authors: Rice Dale W. , Wolman Allen A. , Mate Bruce R. , Harvey James T. 
Published: August 2006

AbstractA school of 41 sperm whales, Physeter macrocephalus, that stranded near the mouth of the Siuslaw River, Oregon (43°59′N, 124°08′W), on 16 June 1979 consisted of 13 males and 28 females. Their ages were estimated by assuming that each postnatal dentin layer represents one year. The males were all sub‐adults, 9.3–11.5 m long and 14–21 yr old. The females were 9.3–11.4 m long, and 11 to about 58 yr old. Ten females were dissected; nine were sexually mature and three were carrying fetuses 2.64–4.62 m long. None of the 28 females was visibly lactating.
GROWTH IN YOUNG GRAY WHALES (ESCHRICHTIUS ROBUSTUS)
Authors: Sumich James L. 
Published: August 2006

AbstractMean body lengths of gray whale calves were found to increase linearly from 4.6 m at birth to 7 m by weaning at six mo. After weaning, rates of length increase diminish, with calves reaching 8 m by one yr of age and 9 m by two yr. Evaluations of the weights of nine gray whales as functions of their measured lengths and girths reduce the emphasis placed on fast‐induced seasonal variations in girth by Rice and Wolman (1971). From birth weights of just under one metric ton, calves double their weights by three mo of age and double again by weaning at six mo.
GEOGRAPHIC PATTERNS OF VARIATION IN OFFSHORE SPOTTED DOLPHINS (STENELLA ATTENUATA) OF THE EASTERN TROPICAL PACIFIC OCEAN
Authors: Schnell Gary D. , Douglas Michael E. , Hough DanielJ. 
Published: August 2006

AbstractThe spotted dolphin (Stenella attenuata), a species commonly associated with the tuna fishery, is widely distributed in the eastern tropical Pacific Ocean (ETP). Geographic patterns in morphological characteristics of this dolphin were evaluated for 36 skull measurements of 574 museum specimens allocated to 5° latitude‐longitude blocks. A strong subdivision between northern and southern offshore populations was demonstrated using principal components, canonical variates and cluster (UPGMA and function‐point) analyses of block means derived from standardized, sex‐adjusted measurements. Classification functions derived from a stepwise multiple discriminant analysis correctly identified more than 87 percent of the specimens as being from either a northern or southern locality. These results support recognition of southern spotted dolphins as a separate management stock. Dolphins from a sample representing a far‐western locality show similarities with those from the south. Patterns of geographic variation in morphology were evaluated using Mantel tests and matrix correlations; 17 of the 36 characters showed regional patterning and 18 exhibited local patterning. Morphological trends were also assessed with respect to 14 oceanographic measures that characterize environmental variability in the ETP. In general, clinal variation in morphology mirrors a north‐south trend found in several environmental variables. Overall, the most striking associations between morphological and environmental variables involved Solar Insolation (Jan.). Sea surface temperatures also exhibited a strong association with morphological variables; the highest correspondence was found between width of the temporal fossa and sea surface temperature in July. In addition, the thickness of the oxygen minimum layer exhibited a pattern of variation that was statistically associated with 58 percent of the skull characters. The geographic patterns found for cranial morphology and environmental measures are strongly clinal and in general congruent, suggesting that oceanographic conditions in part determine trends in morphological characteristics of spotted dolphins.
THE DISTRIBUTION OF BOWHEAD WHALES, BALAENA MYSTICETUS, IN THE CHUKCHI SEA
Authors: Miller R. V. , Rugh D. J. , Ohnson J. H. 
Published: August 2006

AbstractUnder a U.S.‐U.S.S.R. cooperative Marine Mammal Project, shipboard cruises were made in 1979, 1980 and 1982, primarily to determine whether there is a substock of western Arctic bowhead whales (Balaena mysticetus) that summers in the western Chukchi Sea instead of migrating to the Beaufort Sea. More than 100 bowheads were sighted along the north Chukotka coast of Siberia in October 1979, and more than 200 bowheads were sighted there in September 1980. None were seen anywhere in the Chukchi Sea in late July and August 1982. We conclude that the September and October sightings were of animals returning early from the Beaufort Sea and that, other than occurrences peripheral to the main migration, there are no large concentrations in the Chukchi in the summer and there is apparently no western Chukchi substock.
THE EARLIEST SIRENIAN (MAMMALIA: DUGONGIDAE) FROM THE EASTERN PACIFIC OCEAN
Authors: Domning Daryl P. , Ray Clayton E. 
Published: August 2006

AbstractThe partial skull and mandible of an unidentified halitheriine dugongid, collected from the Early Miocene Nye Mudstone in Lincoln County, Oregon, USA, is the earliest record of the Sirenia in the eastern Pacific Ocean. It is probably earlier than Early or Middle Miocene sirenians recently found in Peru, and is definitely earlier than any known from California or Baja California. However, it appears to be slightly younger than fossil sirenian remains recently reported from Late Oligocene rocks in Japan. The Oregon specimen is also the most northern record of the Sirenia on the west coast of North America prior to the Pleistocene although other sirenians did evidently reach and surpass such latitudes by the Late Miocene when a dispersal took place from America to the North Pacific coasts of the Old World. The Oregon specimen probably represents sirenians that spread to the North Pacific from the Caribbean, quite possibly prior to the Miocene. The Nye Mudstone was deposited during the warmest period of the Neogene on the coast of Oregon, and it does not seem necessary to postulate a greater degree of cold‐tolerance for the Oregon sirenian than is exhibited by living sea cows.
THE FOSSIL WHALE, BALAENOPTERA DAVIDSONII (COPE 1872), WITH A REVIEW OF OTHER NEOGENE SPECIES OF BALAENOPTERA (CETACEA: MYSTICETI)
Authors: Demeré Thomas A. 
Published: August 2006

AbstractThe Pliocene fossil whale, Eschrichtius davidsonii Cope 1872, is actually a balaenopterid mysticete referable to the modern genus Balaenoptera Lacépède 1804. Redescription of the holotype of B. davidsonii (a partial left dentary), together with the discovery and description of a nearly complete right dentary referrable to this taxon, demonstrates the taxonomic and systematic affinities of Balaenoptera davidsonii.Although originally thought to be Miocene in age, newspaper accounts of 1872 indicate that the holotype of B. davidsonii was actually collected from fossiliferous sandstones here referred to the San Diego Formation of Late Pliocene age (equivalent to the Blancan North American Land Mammal Age).Comparisons between the dentary of B. davidsonii and dentaries of other extant and fossil balaenopterids allow recognition of several taxonomically useful mandibular characters (i.e., degree of longitudinal curvature of horizontal ramus and form of transverse cross‐sectional outlines). A taxonomic review of other nominal Neogene species of Balaenoptera from Europe and eastern North America is an initial attempt at stabilizing the confusing nomenclatural history and taxonomy of this group. In this regard, the genus Burtinopsis Van Beneden 1872 is placed in synonymy with Balaenoptera.Generic reassignment of the fossil rorqual Balaenoptera davidsonii (Cope 1872) creates a nomenclatural problem of homonymy with the extant minke whale Balaenoptera davidsoni Scammon 1872. As Cope's species is a senior homonym of Scammon's, suppression of Scammon's name is recommended. The new trinomen Balaenoptera acutorostrata scammoni n. ssp. is here proposed for the North Pacific minke whale.
SIZE‐CLASS SEGREGATION OF BOWHEAD WHALES DISCERNED THROUGH AERIAL STEREOPHOTOGRAMMETRY
Authors: Cubbage James C. , Calambokidis John 
Published: August 2006

AbstractBowhead whales (Balaena mysticetus) summering in the eastern Beaufort Sea in 1983 were measured through aerial stereophotogrammetry. Photos were taken from a turbine Aerocommander 690 with wingtip‐mounted, calibrated 35‐mm cameras. Photos were measured on an analytical plotter with scale data provided by radar altimeter and focal length of the lenses. Coefficient of variation of known‐sized targets 12 m long was 1.7 percent (n= 25). Potential duplicate photographs of whales were removed from consideration through an algorithm based on whale swim speed and elapsed time between sightings. Significant segregation by bowhead whale length was found between four broad regions (P < 0.001, ANOVA, Chi square). Also an inverse correlation appeared between longitude and size of animals (P < 0.001), with the larger animals occurring farther east. This unequivocal size‐class segregation confounds an accurate assessment of overall size‐class composition of the population as well as recent attempts to determine calving rate from aerial survey data.
DIEL HAUL‐OUT PATTERNS AND SITE FIDELITY OF HARBOR SEALS (PHOCA VITULINA RICHARDSI) ON SAN MIGUEL ISLAND, CALIFORNIA, IN AUTUMN
Authors: Yochem Pamela K. , Stewart Brent S. , DeLong Robert L. , DeMaster Douglas P. 
Published: August 2006

AbstractWe studied the haul‐out patterns and movements of harbor seals (Phoca vitulina richardsi) on San Miguel Island, California, from 23 October through 6 December 1982 by attaching a radio transmitter to each of 18 seals and monitoring their presence ashore with continuously scanning receivers. Seals hauled out at all hours although, on average, the largest proportion of tagged seals was ashore between 1300 and 1500 h. Median durations of haul‐out bouts of individual seals ranged from 4.7 to 21.8 h; 81% of all haul‐out bouts were less than 12 h and 3% were longer than 24 h. Eighty‐one percent of the seals that were resighted at least twice used only the sites where they were tagged; two seals used two sites and one seal used three. Most seals were hauled out on fewer than 51% of the days sampled. On average, about 41% of tagged seals hauled out each day whereas an average of about 19% was hauled out during peak afternoon hours. Using telemetry data to correct a count of 412 seals made during an aerial survey, we estimated absolute abundance at about 2,168 seals; a modified Peterson mark‐recapture model produced an estimate of about 1,445 seals.
IMPLICATIONS FROM PHYSIOLOGICAL STUDIES OF MARINE MAMMALS1
Authors: Elsner Robert , Wickham Lori L. 
Published: August 2006

AbstractSome aspects of captive marine mammal research have become matters of controversy, largely due to a misunderstanding of the value of such studies and of their importance to effective management and conservation of these species. Understanding of the physiological mechanisms underlying the special adaptations for aquatic life that marine mammals demonstrate provides essential information relating to their health and survival. The need for such information is increasing as disturbance of the world's marine environments steadily escalates. While studies of these animals in their natural habitats contribute much to our comprehension of their biology, a more complete understanding of the physiological basis of their behavior depends upon experimental laboratory investigations. Some of the new knowledge thus gained has potentially important implications for human medicine.
BEHAVIORAL AND PHYSIOLOGICAL MEASUREMENTS OF MATERNAL INVESTMENT IN THE STELLER SEA LION, EUMETOPIAS JUBATUS
Authors: Higgins Lesley V. , Costa Daniel P. , Huntley Anthony C. , Le Boeuf Burney J. 
Published: August 2006

AbstractThe onshore and at‐sea cycles of females, suckling behavior of pups and their milk intake were studied in Steller sea lions (Eumetopias jubatus) during 1983 at Año Nuevo Island, California. Females averaged approximately 21 h ashore and 36 h at sea. The trips to sea lengthened as pups aged, resulting in an overall decline in female time ashore to 30% by the sixth week following parturition. Activity budgets of pups showed no significant differences among suckling time, age and sex. Milk intake, estimated using labeled water studies, revealed that heavier pups consumed more milk than lighter ones (milk ingestion in ml/d = 4.26 + 0.0687 [Pup Mass in kg]). Mean milk intake was 1.78 ± 0.33 liters/d. Mean pup growth rate was 0.38 ± 0.1 kg/d. The results suggest that female attendance patterns are shaped by the increasing nutritional demands of growing pups and their increasing efficiency at suckling.
A COPROLOGICAL SURVEY OF HELMINTH PARASITES OF THE HAWAIIAN MONK SEAL FROM THE NORTHWESTERN HAWAIIAN ISLANDS
Authors: Dailey Murray D. , Santangelo Richard V. , Gilmartin William G. 
Published: August 2006

AbstractIn conjunction with an Hawaiian monk seal, Monachus schauinslandi, breeding enhancement program, fecal samples were examined for the presence of helminth parasite products (eggs, larvae, and proglottids). Eighty‐two samples were examined from four island groups in the northwestern Hawaiian Islands: 38 from Kure Atoll, 32 from French Frigate Shoals, 11 from Laysan Island, and one from Lisianski Island. Identified helminth products include those of Diphyllobothrium sp., D. cameroni, Contracaecum turgidum, Anisakis sp., Corynosoma rauschi, and Trematoda. In addition, eggs from Halarachne laysanae (Atari) were found in 3 samples. Eggs of C. turgidum were present in the highest percentage (>64%) of samples from all locations. Eggs of Anisakis sp. and Trematoda are reported from this host for the first time.
GEOGRAPHIC VARIATION IN TOOTH MORPHOLOGY AND DENTINAL PATTERNS IN THE SPINNER DOLPHIN, STENELLA LONGIROSTRIS
Authors: Akin Priscilla A. 
Published: August 2006

AbstractSixteen tooth characters were analyzed in 277 specimens of spinner dolphins (Stenella longirostris) from the eastern tropical Pacific to determine whether the characters were associated with size of the animal, species‐stock membership or geographic location. The tooth characters included 5 continuous measurements and 11 qualitative variables. Statistical analyses of the characters included two‐way ANOVA tests which assessed continuous measurement variables for differences based on stock membership, latitude and longitude of collection or whether the animal was collected north or south of the equator. Principal component analyses combined factors of continuous variables with those of qualitative variables into components which were used as variables in further analyses. Discriminant analyses were performed using continuous variables alone and using principal components as potentially discriminating variables. Results showed that tooth differences were not associated with size but significant differences were found in some tooth variables with stock membership, incremental changes in latitude and whether the animal was collected north or south of the equator. A discriminant function, containing only tooth length, correctly classified 67% of northern and 78% of southern animals according to location of collection north or south of the equator.
THE DISTRIBUTION OF WHITE‐SIDED (LAGENORHYNCHUS ACUTUS) AND COMMON DOLPHINS (DELPHINUS DELPHIS) VS. ENVIRONMENTAL FEATURES OF THE CONTINENTAL SHELF OF THE NORTHEASTERN UNITED STATES
Authors: Selzer Lawrence A. , Payne P. Michael 
Published: August 2006

AbstractSightings of white‐sided (Lagenorhynchus acutus) and common dolphins (Delphinus delphis) from survey vessels operating on the continental shelf of the northeastern United States were recorded during spring and fall of six years. Distributions of these sightings were compared with sea surface temperature and salinity, and bottom topography. The apparent geographic distributions of the two species are complementary, although there is a broad overlap. White‐sided dolphins occurred primarily within the Gulf of Maine, but also on Georges Bank and in the mid‐Atlantic region. Common dolphins were abundant within a broad band paralleling the continental slope (100–200 m depth contour) from latitude 35°N to the northeast peak of Georges Bank. Sightings of this species were distributed primarily along the edge of the continental shelf south of 40°N in spring and north of this latitude in fall. Few sightings of common dolphins occurred in the Gulf of Maine.Although both species of dolphins were sighted more frequently in areas of high sea floor relief, white‐sided dolphins occurred in areas where sea surface temperatures and salinities are low while common dolphins were sighted in warmer, more saline waters. However, these environmental conditions may be only secondarily influencing dolphin distribution. Seasonal variation in sea surface temperature and salinity, and local nutrient upwelling in areas of high sea floor relief may affect preferred prey abundances, which in turn may affect dolphin distribution.
DYNAMIC RESPONSE ANALYSIS. III. A CONSISTENCY FILTER AND APPLICATION TO FOUR NORTHERN ELEPHANT SEAL COLONIES
Authors: Boveng Peter , DeMaster Douglas P. , Stewart Brent S. 
Published: August 2006

AbstractDynamic response analysis, a technique for determining stock size relative to the maximum net productivity level (MNPL), was applied to northern elephant seal populations from the South Farallon Islands, Año Nuevo Island, San Nicolas Island and San Miguel Island. Pup counts were used as indices of population size. The application of dynamic response analysis presented here involved some methodological innovations. We present a moving interval method which involves calculating separate dynamic response analyses for intervals of various lengths ranging from four counts to the total number available for the colony. The sign of the second order polynomial regression coefficient computed from a particular interval was used to indicate the colony's apparent status (relative to its MNPL, += above MNPL, ‐ = below MNPL) on that interval. Consistency in the sign of the second order coefficient, as the interval was moved along the trajectory, was used to determine the minimum reliable interval size. Each colony exhibited growth similar to that of a population below its MNPL. These results are consistent with recent natural history observations at San Nicolas, San Miguel and the South Farallon islands. Natural history observations at Año Nuevo Island suggest that the colony there is now at equilibrium. Thus, if our results from dynamic response analysis of the Ano Nuevo colony are correct, it appears that the MNPL may be close to the carrying capacity for these animals.
LONG‐TERM TRENDS IN ABUNDANCE AND DISTRIBUTION OF MANATEES (TRICHECHUS MANATUS) IN THE NORTHERN BANANA RIVER, BREVARD COUNTY, FLORIDA
Authors: Provancha J. A. , Provancha M. J. 
Published: August 2006

AbstractFour aerial survey projects were conducted between 1977 and 1986 to determine the abundance, density and distribution of West Indian manatees (Trichechus manatus), in the northern Banana River, Kennedy Space Center, Florida. Manatee density and distribution within selected portions of the 78.5 km2 study area were determined. Peak numbers of manatees occurred in spring of each year. The maximum counts increased from 56 in 1978 to 297 in 1986. Manatee abundance was lowest in the winter of each year. Mean density per flight increased from 0.52 manatees/km2 in 1977–78 to 2.73/km2 in 1984–86. This increase may reflect increases in the east coast population or shifts in the population distribution. Distributional changes were observed in the study area through time, with a lower percentage of manatees occurring in industrial areas and a correspondingly higher percentage of manatees in nonindustrial areas by 1985.
GENETIC RELATEDNESS OF TWO POPULATIONS OF THE SOUTHERN ELEPHANT SEAL, MIROUNGA LEONINA
Authors: Gales Nicholas J. , Adams Mark , Burton Harry R. 
Published: August 2006

AbstractBlood samples from southern elephant seals (Mirounga leonina) from Heard and Macquarie Islands were surveyed electrophoretically for protein variation. Thirty proteins encoded by a minimum of 35 loci were screened, four of which were found to be polymorphic. Statistically significant differences in allele frequencies were found between the two populations at three loci. Heterozygosity estimates for the Heard and Macquarie island populations were 0.034 ± 0.020 (mean ± standard error) and O.029 ± 0.017 respectively, with a Nei distance of 0.007. The findings suggest that the two populations may have diverged genetically and very limited gene flow exists between the islands, a finding consistent with limited information from mark‐recapture studies.