bluuebunny/crossref_metadata_2025_split huggingface dataset:
GRAY WHALES (ESCHRICHTIUS ROBUSTUS) OFF SAKHALIN ISLAND, RUSSIA: SEASONAL AND ANNUAL PATTERNS OF OCCURRENCE1
Authors: Weller David W. , Würsig Bernd , Bradford Amanda L. , Burdin Alexander M. , Blokhin Sergey A. , Minakuchi Hiroya , Brownell Robert L. 
Published: August 2006

AbstractThe annual return, seasonal occurrence, and site fidelity of Korean‐Okhotsk or western gray whales on their feeding grounds off northeastern Sakhalin Island, Russia, were assessed by boat‐based photo‐identification studies in 1994‐1998. A total of 262 pods were observed, ranging in size from 1 to 9 whales with an overall mean of 2.0. Sixty‐nine whales were individually identified, and a majority of all whales (71.0%) were observed in multiple years. Annual sighting frequencies ranged from 1 to 18 d, with a mean of 5. 4 d. The percentage of whales reidentified from previous years showed a continuous annual increase, reaching 87.0% by the end of the study. Time between first and last sighting of identified individuals within a given year was 1‐85 d, with an overall mean of 40.6 d. Annual calf proportions ranged from 4.3% (1997) to 13.2% (1998), and mother‐calf separations generally occurred between July and September. The seasonal site fidelity and annual return of whales to this part of the Okhotsk Sea emphasize its importance as a primary feeding ground for this endangered population.
THE EFFECTS OF ACOUSTIC ALARMS ON THE BEHAVIOR OF HARBOR PORPOISES (PHOCOENA PHOCOENA) IN A FLOATING PEN
Authors: Kastelein R. A. , Rippe H. T. , Vaughan N. , Schooneman N. M. , Verboom W. C. , Haan D. De 
Published: August 2006

AbstractIn an attempt to test the effectiveness of sounds in deterring harbor porpoises from nets and reducing porpoise bycatch in gill net fisheries, two harbor porpoises, kept in a large floating pen at Neeltje Jans, The Netherlands, were subjected to 3 different underwater sounds. The effect of each sound was judged by comparing the animals' behavior during a 15‐min test period with that during a 15‐min baseline period immediately before the test and a 15‐min recovery period immediately after the test. The effects of the alarms were quantified as the distance between the porpoises' surfacings and the alarm and the animals' respiration rates. Each alarm was tested in two positions in the pen. The behavior observed was related to the sound‐pressure‐level distribution in the pen. All three alarms: the standard Dukane alarm (a commercially available alarm with a regular pulse interval of 4.3 sec used to deter dolphins from fishing nets), the random Dukane alarm (the same alarm with random pulse interval of between 2 and 30 sec), and the “bird alarm” (a sound from a generator) resulted in increases in both the distance of the animals' surfacings from the alarms and their respiration rates. The standard Dukane alarm and the bird alarm were more effective than the random Dukane alarm in inducing the animals to swim away from the sound source.
HABITAT USE AND PREFERENCES OF INDO‐PACIFIC HUMPBACK DOLPHINS SOUSA CHINENSIS IN ALGOA BAY, SOUTH AFRICA
Authors: Karczmarski Leszek , Cockcroft Victor G. , Mclachlan Anton 
Published: August 2006

AbstractThis paper examines environmental and behavioral determinants of the habitat use and preferences of Indo‐Pacific humpback dolphins inhabiting the Algoa Bay region on the south Eastern Cape coast of South Africa. In order to quantify the habitat use and preference, two indices were used, the Coefficient of Area Use (AU) and the Activity Index (AI). The dolphins inhabit a narrow strip of shallow, inshore waters of Algoa Bay and remain mostly within 400 m of the shore, in water less than 15 m deep, with no apparent preference for clear or turbid water. Water depth is probably the main factor limiting their inshore distribution, and the 25‐m isobath seems to represent the critical depth. Within this confined, inshore distribution, dolphin activities concentrate in the vicinity of rocky reefs‐their primary feeding grounds. Dolphin dependence on these shallow‐water habitats is evident throughout the year and, consequently, the inshore shallow reefs are identified as the “key habitat” which is of primary importance for humpback dolphins in Eastern Cape waters. The dolphins' dependence on this restricted type of habitat within an already restricted inshore distribution makes them particularly vulnerable to alteration or loss of this habitat.
LASER SAFETY THRESHOLDS FOR CETACEANS AND PINNIPEDS
Authors: Zorn Heather M. , Churnside James H. , Oliver Charles W. 
Published: August 2006

AbstractAn increase in the use of oceanographic lidar has raised concern over laser safety for marine mammals. We were able to address some of these concerns by combining information about current laser safety standards, retinal damage mechanisms for humans, and research on eye anatomy for humans, cetaceans, and pinnipeds. To estimate the irradiance at the retina, the image size at the retina and pupil diameter must be known. We estimate the smallest spot size using retinal resolution or visual acuity for six species of cetaceans and five species of pinnipeds. A sensitivity ratio was calculated for each species using the ratio of the irradiance at the retina of the marine mammal to the irradiance at the retina of humans. The sensitivity ratio was used to suggest exposure limits for the various species. Because the human eye is more sensitive than either the cetacean or pinniped eye, we conclude that laser energies that are eye‐safe for humans will also be safe for marine mammals, and higher laser irradiances may be permissible if illumination of humans is avoided.
SURFACE BEHAVIOR OF BOTTLENOSE DOLPHINS IS RELATED TO SPATIAL ARRANGEMENT OF PREY
Authors: Acevedo‐Gutiérrez Alejandro , Parker Nadine 
Published: August 2006

AbstractWe tested the hypothesis that spatial arrangement and movements of bottlenose dolphins (Tursiops truncatus) are related to the spatial arrangement of their prey. From 65 groups we: (1) classified feeding behavior of dolphins according to spatial arrangement and movements of individuals; (2) assessed spatial arrangement and location of prey from direct observations, numbers of associated seabirds, and echosounder recordings; and (3) related feeding behavior of dolphins to spatial arrangement and location of prey. Four feeding categories were defined from cluster and principal component analyses: (1) moving rapidly with no diving, (2) milling with no diving, (3) diving in several locations, and (4) diving in one location. These feeding categories were related to spatial arrangement and location of prey.
THE DIET OF GALÁPAGOS SPERM WHALES PHYSETER MACROCEPHALUS AS INDICATED BY FECAL SAMPLE ANALYSIS
Authors: Smith Sean C. , Whitehead Hal 
Published: August 2006

AbstractFecal samples were collected while following sperm whales (Physeter macrocephalus) off the Galápagos Islands, Ecuador. They contained 133 upper beaks and 164 lower beaks of cephalopods. Analysis of the lower beaks suggests that the sperm whales fed primarily on three genera of cephalopods; Histioteutbis (62%), Ancistrocbeirus (16%), and Octopoteutbis (7%). The beak dimensions indicate that the cephalopods ranged in mantle length from 5 to 54 cm and in mass from 12 to 650 g. Fecal samples varied significantly between five study years and over different parts of the study area, but the number of beaks collected per sample did not correlate significantly with defecation rate (a measure of feeding success). Using beak material from fecal samples gives a biased estimate of sperm whale diet, reducing the frequencies of very small and very large cephalopods. However, all other available methods of assessing sperm whale diet also possess biases.
IDENTIFYING DIURNAL FORAGING HABITAT OF ENDANGERED HAWAIIAN MONK SEALS USING A SEAL‐MOUNTED VIDEO CAMERA
Authors: Parrish Frank A. , Craig Mitchell P. , Ragen Timothy J. , Marshall Gregory J. , Buhleier Birget M. 
Published: August 2006

AbstractThe Hawaiian monk seal (Monachus schauinslandi) is thought to be a foraging generalist, preying on numerous species in diverse habitats of the subtropical Northwestern Hawaiian Islands. At the atoll of French Frigate Shoals, recent evidence of emaciation and low survival in monk seals prompted a search for their specific prey communities and foraging habitat.A video camera (National Geographic Television's CRITTERCAM) fitted to 24 adult male seals documented benthic and demersal foraging on the deep slopes (50‐80 m) of the atoll and neighboring banks. The number of bottom searches for prey was compared by year, time of day, type of bottom, individual seal, and length of bottom time. Analysis of variance identified a significant interaction of seal and bottom type, explaining 65% of the total variance. Seals fed on communities of cryptic fauna (fish and large invertebrates) in transitional “ecotone” regions of low relief where consolidated substrate, rubble, and talus bordered areas of sand. Independent areal surveys of bottom types throughout the atoll and neighboring banks suggest that the type of bottom selected as foraging habitat represents a relatively small percentage of the total benthic area available.
THE NORTHEASTERN ALBORAN SEA, AN IMPORTANT BREEDING AND FEEDING GROUND FOR THE LONG‐FINNED PILOT WHALE (GLOBICEPHALA MELAS) IN THE MEDITERRANEAN SEA
Authors: Cañadas Ana , Sagarminaga Ricardo 
Published: August 2006

AbstractLittle is known about the long‐finned pilot whale's population size, structure, distribution, and dynamics in the Western Mediterranean basin. The research region covered since 1992 in southeast Spain, at the edge of the Alboran Sea, is considered an important oceanographic transition zone between the Mediterranean and the Atlantic Ocean. The research ship Toftevaag carried out surveys covering a total of 10,173 nmi (18,840 km) from April to September each year, 1992‐1997, all years pooled. Effort for ten‐by‐ten‐mile quadrants was stratified by depth and sea state to ascertain encounter rates. Tracking was used together with photo‐identification of animals to analyze home range of groups. Behavior was recorded ad libitum, and underwater video taping was used to analyze specific behavior patterns. One hundred and nine sightings of pilot whales were made. The average group size was 41.4 ± 58.4, ranging from 1 to 350. The average depth at encounters was 848.7 ± 281.2 m ranging from 300 to 1,800 m. Compatison of results for encounter rate and group size with those for other Mediterranean regions, together with site fidelity shown by photo‐identification and observations of reproductive behavior, reflect the importance of the Alboran Sea to the species in the Mediterranean.
AERIAL VIDEOGRAMMETRY FROM A TETHERED AIRSHIP TO ASSESS MANATEE LIFE‐STAGE STRUCTURE
Authors: Flamm Richard O. , Owen Edward C. G. , Owen Caryn F. W. , Wells Randall S. , Nowacek Doug 
Published: August 2006

AbstractAerial videogrammetry from an airship tethered to a boat was used to assess the life‐stage structure of manatees in the Blue Waters area of the Homosassa River on the west coast of central Florida. Individual frames of videos were loaded onto a computer and lengths of manatees measured using graphics software. All images of manatees were measured independently by three observers. Measurements were transformed to total manatee lengths by calculating the ratio between the measurements of a reference object of known length and the measurement of the manatee. Length estimates were highly variable but were unbiased with respect to observer. Results of an analysis of variance suggested that the hypothesis that lengths differed among days and among observers should not be rejected. Life‐stage structures were represented in three schemes. One scheme‐which included four life stages: dependent calves, juveniles, animals in tramsition between juvenile and adult, and adults‐was included to provide the most information without sacrificing confidence in the life‐stage distribution. Overall, the video system was effective at capturing images of manatees for life‐stage characterization and, with improvements in image resolution, could become a valuable tool for photo‐identification in sight‐resight experiments.
USE OF PHOTOGRAPHIC IDENTIFICATION IN CAPTURE‐RECAPTURE STUDIES OF MEDITERRANEAN MONK SEALS
Authors: Forcada Jaume , Aguilar Alex 
Published: August 2006

AbstractThe use of photo‐identification and its reliability in capture‐recapture studies of Mediterranean monk seals were assessed using slides collected in the colony at Cap Blanc, western Sahara, from 1993 to 1996. Five tests indicated that researchers involved in photo‐identification were proficient in matching slides of identified seals, consistent in classifying the side of the seal shown in slides and in assigning the morphological stage of the seal, and that changes of markings over a period of three years were insufficient to affect matching success. The certainty of identifying a seal was not dependent on the number of slides used but on distinctiveness of the markings and the quality of the slides taken. Capture‐recapture abundance estimates were biased upwards when including poor quality slides. The exclusive use of excellent‐ and good quality slides provided the best estimates. The proportion of distinctive seals varied between morphological stages and was significantly lower in juveniles. When including the identification histories of juveniles, the heterogeneity of capture probabilities was higher. Therefore, abundance estimates were less biased when all juveniles were considered as non‐distinctive seals. Reliable abundance estimates required a balance between duration of capture occasions and time interval between these.
SURVIVAL RATES OF SEA OTTER PUPS IN ALASKA AND CALIFORNIA
Authors: Monnett Charles , Rotterman Lisa Mignon 
Published: August 2006

AbstractAdult female sea otters (Enhydra lutris) were instrumented with implanted radio‐transmitters in Prince William Sound (PWS), Alaska, and survival rates were estimated for their dependent pups. Overall, 94 of 141 (67%) of the pups studied survived to a minimum age of 120 d and were assumed to have successfully weaned. Survival of pups in six cohorts ranged from 53% to 88%. The mean interval between successive visual observations was 12.5 d. For these calculations, the assumption was made that pups were successfully weaned if they accompanied mothers for at least 120 d. Estimated survival rates were different when this assumption was changed to either 90 d or 150 d (73% and 52%, respectively).Females were palpated for pregnancy when instrumented. Of 19 believed to be pregnant, 17 were subsequently seen with young pups giving a detection rate for births of 89.5%. When the above observed survival rate of pups was adjusted for undetected births, the estimated overall survival rate for the study population was 60% (120 d minimum dependency).Survival rates of pups in PWS and a population at Kodiak Archipelago (KOD) (Monson and DeGange 1995) were compared with that of pups in the population in California (CA, four studies). These data did not support the hypothesis that survival rates were lower in California (CA: 103/160, Psurv. 0.64; PWS: 94/141, Psurv.= 0.67; KOD: 19/23, Psurv.= 0.83; pairwise comparisons, X2, P > 0.05). Comparison of pup survival rates among studies was hindered by small sample sizes, methodological differences, and lack of detail about assumptions underlying estimates.
NEW GENUS OF DORUDONTINE ARCHAEOCETE (CETACEA) FROM THE MIDDLE‐TO‐LATE EOCENE OF SOUTH CAROLINA
Authors: Uhen Mark D. , Gingerich Philip D. 
Published: August 2006

AbstractA new archaeocete whale from the late middle or early late Eocene of South Carolina, Chrysocetus healyorum gen. et sp. nov., is described on the basis of a single subadult specimen. This individual includes: a partial skull; hyoid apparatus; lower jaws; teeth; all cervical, some thoracic and some lumbar vertebrae; ribs and sternum; left forelimb elements; and pelves. The specimen includes portions of much of the body, but while some of the bones are fairly complete, others are damaged, particularly the skull. The pelves resemble those of Basilosaurus, documenting a similar stage of hind limb reduction in dorudontines and suggesting that Chrysocetus was not able to support its body on land. The acetabulum for articulation of the femur is well formed and indicates that the hip joint was functional. Chrysocetus is distinguishable from other described dorudontines based on body size, characteristics of the teeth, and forelimb elements. Absence of deciduous teeth in a subadult individual of Chrysocetus may be indicative of an early stage of the evolution of monophyodonty.
COLLISIONS BETWEEN SHIPS AND WHALES
Authors: Laist David W. , Knowlton Amy R. , Mead James G. , Collet Anne S. , Podesta Michela 
Published: August 2006

AbstractAlthough collisions with motorized ships are a recognized source of whale mortality, little has been done to compile information on the frequency of their occurrence or contributing factors. We searched historical records and computerized stranding databases for evidence of ship strikes involving great whales (i. e., baleen whales and the sperm whale). Historical records suggest that ship strikes fatal to whales first occurred late in the 1800s as ships began to reach speeds of 13‐15 kn, remained infrequent until about 1950, and then increased during the 1950s‐1970s as the number and speed of ships increased. Of 11 species known to be hit by ships, fin whales (Balaenoptera physalus) are struck most frequently; right whales (Eubalaena glacialis and E. australis), humpback whales (Megaptera novaeangliae), sperm whales (Physeter catodon), and gray whales (Escbricbtius robustus) are hit commonly. In some areas, one‐third of all fin whale and right whale strandings appear to involve ship strikes. To assess contributing factors, we compiled descriptions of 58 collisions. They indicate that all sizes and types of vessels can hit whales; most lethal or severe injuries are caused by ships 80 m or longer; whales usually are not seen beforehand or are seen too late to be avoided; and most lethal or severe injuries involve ships travelling 14 kn or faster. Ship strikes can significantly affect small populations of whales, such as northern right whales in the western North Atlantic. In areas where special caution is needed to avoid such events, measures to reduce the vessel speed below 14 kn may be beneficial.
PHOTOGRAPHIC IDENTIFICATION OF NORTHERN BOTTLENOSE WHALES (HYPEROODON AMPULLATUS): SOURCES OF HETEROGENEITY FROM NATURAL MARKS
Authors: Gowans Shannon , Whitehead Hal 
Published: August 2006

AbstractThe use of natural marks in capture‐recapture studies can lead to unequal capture probabilities. This paper examined a catalog of northern bottlenose whale (Hyperoodon ampullatus) photographs from the Gully, Nova Scotia, to identify potential sources of heterogeneity. This information can be used to select appropriate individuals and photographs to include in analyses. Individual northern bottlenose whales were sufficiently marked to uniquely identify individuals (x̄= 14.5 marks/individual; range 1‐67), but not all mark types persisted over time. Reliable marks were defined as mark types that were not lost over the nine‐yeat study period (notches, back indentation, and mottled patches). Individuals were considered reliably marked if they possessed at least one back indentation or mottled patch (located within one dorsal fin width, at the base of the dorsal fin) or a notch on the dorsal fin. Sixty‐six percent (SE = 5%) of the population were reliably marked. Longterm analyses (months to years) should use only reliably marked individuals, and the results scaled to account for the rest of the population. Our results also showed that photographic quality affected an observer's ability to identify individuals. For this catalog, quantitative analysis indicated only photographs of Q ≥ 4 (on a 6‐point scale with 6 representing the highest quality) should be included in mark‐recapture analyses sensitive to heterogeneity.
NO EVIDENCE OF ACCOMMODATION IN THE EYES OF THE BOTTLENOSE DOLPHIN, TURSIOPS TRUNCATUS
Authors: Litwiler Tricia L. , Cronin Thomas W. 
Published: August 2006

AbstractBottlenose dolphins (Tursiops truncatus) are aquatic mammals that must come to the surface to breathe. As a result, it might be expected that their eyes are adapted for both aerial and underwater vision. Earlier studies suggest that dolphins are emmetropic (i. e., focused at infinity) in water, and in some cases, emmetropic in air, although the mechanisms that permit these animals to see well in both media are not well understood. Nor is it known whether they can accommodate to focus sharply on objects at different distances. We employed video photoretinoscopy to investigate the possibility of an active accommodative mechanism in the eyes of the bottlenose dolphin in water. Measurements of the refractive state in water indicated near emmetropia for two individuals and slight myopia (nearsightedness) for the third individual. No clear cases of accommodation were observed underwater in any of the subjects examined. Vision underwater may be used to supplement echolocation. If so, such a role might not require an accommodative mechanism.
INTERACTIONS OF SINGING HUMPBACK WHALES WITH OTHER MALES
Authors: Darling James D. , Bérubé Martine 
Published: August 2006

AbstractTwo non‐mutually exclusive hypotheses on the function of the humpback whale song are: (1) it attracts females to the male singer; (2) it is a male‐male display, that may order status. To evaluate these, from 24 January‐13 April 1997 off Maui, Hawaii, 42 singers were located, audio‐recorded, photo‐identified and monitored for interactions with other whales. Whales that joined singers were biopsy sampled for molecular determination of sex. In 76% (32 of 42) of the interactions, a lone non‐singing adult joined the singer. In the remainder, singers stopped singing and joined a nearby group or accompanied other whales. In 81% (26 of 32) instances where a lone adult joined a singer, the pair split again within minutes; otherwise a group formed. In one such group the pair became a trio and eventually joined a competitive group. Behavior in joining/splitting interactions ranged from a single pass‐by, to surface activity such as tail lobs and breaches. The sex of 22 joiners was determined: 14 genetically and eight behaviorally. All were males. Humpback whale song preceded, and at times followed, male‐male interactions of variable duration and agonistic level in and around the breeding season. If considered within the context of a proposed dominance polygyny mating system, these observations appear to support speculation that the song may function in male social ordering.