bluuebunny/crossref_metadata_2025 huggingface dataset:
THERMOREGULATORY ADAPTATIONS IN MARINE MAMMALS: INTERACTING EFFECTS OF EXERCISE AND BODY MASS. A REVIEW1
Authors: Whittow G. C.
Published: August 2006

Abstract

A review of thermoregulation in marine mammals led to the following conclusions: very little is known about thermoregulation in large cetaceans. The only measured value for the metabolic rate of a whale, albeit a young one, was substantially higher than the predicted value for a terrestrial mammal of similar size. Very small and newborn marine mammals rely on a high metabolic heat production to sustain their body temperature during exposure to cold or in the water. The considerable insulation of some adult marine mammals may absolve them from the need for a high level of heat production. One marine mammal in tropical or subtropical waters is hypometabolic. There is evidence for a powerful control of thermoregulatory mechanisms by the anterior hypothalamic/preoptic region of the brain in two species. Thermoregulation in marine mammals during exercise remains paradoxical.
USING ORGANOCHLORINE POLLUTANTS TO DISCRIMINATE MARINE MAMMAL POPULATIONS: A REVIEW AND CRITIQUE OF THE METHODS1
Authors: Aguilar Alex
Published: August 2006

Organochlorine pollutants are potentially useful for identifying discrete populations of marine mammals that overlap in geographic distribution. However, many factors unrelated to geographical distribution may affect the chemical burden of individual animals or of entire population components even within a homogeneously distributed population. These factors include. among others, nutritional state, sex, age, trophic level, distance of habitat from mainland and pollution source, excretion. metabolism, and tissue composition. Sample storage and analytical methodology may also be an important source of variation. These, and any other factors, must be identified and their effect ascertained before attempting any comparison between populations. This paper critically examines the nature and magnitude of the effects of these factors on organochlorine tissue loads in marine mammals. Pollutant concentrations can be strongly biased if carefully designed sampling regimes are not followed, but they are affected only moderately by sample treatment after collection. Conversely, ratios between concentrations of compounds, such as the DDE/tDDT or the tDDT/PCB ratios, seem less dependent on sampling regime but more affected by storage. analytical procedures and ecological variations such as distance from pollutant source or trophic level. Taking these effects into account, advice is provided about sampling and strategies for selection of variables that will improve the reliability of the comparisons between populations.
STATISTICAL METHODS FOR ESTIMATING NUMBERS OF CAPE FUR SEAL PUPS FROM AERIAL SURVEYS
Authors: Cressie N. A. C. , Shaughnessy P. D.
Published: August 2006

Abstract

The Cape fur seal Arctocephalus pusillus of South Africa and Namibia breeds in 23 colonies. Aerial surveys have been used to estimate numbers of pups during breeding seasons from December 1971 to December 1978, and the results have been presented by Shaughnessy (1987). In this paper we develop statistical methods for estimating these pup numbers, as well as variances of the estimates. We demonstrate a significant increase in numbers of seal pups between 1971 and 1976; the rate of increase is estimated to be 3.2% per annum.
A METHOD TO COLLECT AND PROCESS SKIN BIOPSIES FOR CELL CULTURE FROM FREE‐RANGING GRAY WHALES (ESCHRICHTIUS ROBUSTUS)
Authors: Mathews Elizabeth A. , Keller Steven , Weiner David B.
Published: August 2006

For researchers studying mysticere whales few methods for determining gender or for collecting biochemical and genetic information from unrestrained animals are available. The objective of this study was to develop a reliable method for collecting viable tissue samples for establishing continuous cell cultures from skin biopsies of free‐ranging whales. A method to collect and process these samples is presented. Six of seven skin biopsies from gray whales were established in cell culture. Our results suggest that the viability of the samples is improved by (1) sterile processing in the field, (2) minimizing the time between collection and delivery to the cell culture facility, (3) reducing the concentration of antifungal agent, and (4) placing tissue explants under a coverslip. While the results reported in this paper are based on a small sample size, we believe that if the procedures are followed, they will increase the probability of successfully culturing cetacean tissue. Established cell lines can supply replenishable material from identified whales still living in the wild. These cultures can then be used for determination of sex from karyotypes, and for assessing genetic relationships of cetaceans from inherited protein, chromosomal and DNA polymorphisms. These much needed analytical tools can be used to determine familial and populational relationships, leading to a better understanding of mating systems, stock identification and effective population sizes of wild cetaceans.
THE ASSESSMENT OF COMPETITION BETWEEN SEALS AND COMMERCIAL FISHERIES IN THE NORTH SEA AND THE ANTARCTIC1
Authors: Harwood John , Croxall John P.
Published: August 2006

Most of the exploited fish stocks in the North Sea are also used as a food supply by a number of seal species; the same is true for some fish and invertebrate stocks in the Antarctic—although the fisheries there are, at present, much smaller than those in the North Sea. The information needed for a critical assessment of such interactions is reviewed. Using existing techniques it is possible to estimate the quantity and size‐classes of each fish or invertebrate species consumed by seals and to compare this with the commercial catch. If fishing mortality is known, these estimates can be used to calculate the level of mortality imposed by the seals. However, a realistic evaluation requires information on the distribution and movements of the fish, the seals' feeding effort, and the fisheries effort in time and space. At present it is difficult or impossible to obtain this information, but recent technological developments in telemetry equipment will soon make it feasible. To assess the economic effects of changes in seal numbers on the fishery, or the ecological effects of changes in fisheries effort on seal populations, requires additional information on the responses of the fishery and the seals to changes in fish abundance, and of the commercial market to changes in the supply of fish.
CAPACITY AND MODE OF PCB METABOLISM IN SMALL CETACEANS1
Authors: Tanabe Shinsuke , Watanabe Seiji , Kan Hiroshi , Tatsukawa Ryo
Published: August 2006

Based on a comparative approach using PCB isomer and congener compositions in higher animals and their food organisms, the capacity and mode of PCB metabolism in small cetaceans were studied and the following conclusions were drawn: (1) Small cetaceans can metabolize some of the lower chlorinated biphenyls and this capacity seems to be the same in all species of these animals. (2) The values of MI, an index to evaluate the capacity of PCB metabolism, showed that the metabolic capacity of small cetaceans was extremely low as compared to those of birds and terrestrial mammals. (3) The structural requirements for PCB metabolism were different in animal species, in that small cetaceans have no capacity to metabolize a group of PCBs with adjacent non‐chlorinated meta and para carbons in biphenyl rings. (4) No development of PB (phenobarbital)‐type enzymes, and a lower activity of MC (3‐methylcholanthrene)‐type enzymes were suggested in small cetaceans, which implies long‐term accumulation and possible reproductive toxicity of persistent organochlorines in these animals. The present approach should provide an important insight into the physiological responses of small cetaceans to persistent toxic chemicals.
RAY ENCOUNTERS AS A MORTALITY FACTOR IN ATLANTIC BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS)
Authors: Walsh Michael T. , Beusse Deke , Bossart Gregory D. , Young W. Glenn , Odell Daniel K. , Patton Geoffrey W.
Published: August 2006

Ray spines were found associated with various tissues on necropsy of seven Atlantic bottlenose dolphins (Tursiops truncatus). In at least six cases they were considered a major factor in the death of the animal. Three mature Tursiops had ray spines located in the lung parenchyma. In two other dolphins the ray spine punctured the lateral chest wall without entering the lung tissue. A sixth Tursiops contained a ray spine located in the liver tissue, while a seventh animal had a ray spine lodged in the pancreas. Five of the dolphins were wild individuals and two had been in captivity for more than one year. These findings indicate that beached dolphins and dolphins in captivity with a chronic history of illness should be examined for the presence of ray spines. Caution should be used in maintaining mixed exhibits of dolphins with stingray species.
DYNAMIC RESPONSE ANALYSIS. I. QUALITATIVE ESTIMATION OF STOCKSTATUS RELATIVE TO MAXIMUM NETPRODUCTIVITY LEVEL FROMOBSERVED DYNAMICS
Authors: Goodman Daniel
Published: August 2006

A qualitative determination of whether a population is above or below its MNPL can be carried out under circumstances where the value of the MNPL itself, and other details of the production curve, cannot be estimated. This qualitative assessment may often be sufficient for management decisions. The method proceeds by locally approximating the production curve, in the neighborhood of the present population density, from data on population sizes and harvests, and then determining whether this represents the ascending or descending arm of the curve. When the harvests are small, or when the harvests are a constant fraction of the production, the population‐size data need only be relative. With adequate quantities of data, this assessment method can accommodate random measurement error and random perturbations in the dynamics of the population system.
DYNAMIC RESPONSE ANALYSIS. II.EVALUATION OF DYNAMIC RESPONSE ANALYSIS IN A SIMULATED NO‐HARVEST CASE
Authors: Gerrodette Tim
Published: August 2006

A new method of stock assessment, dynamic response analysis, allows a qualitative assessment of stock status relative to its level of maximum net productivity to be carried out with minimal data. This paper evaluates the performance of dynamic response analysis on a simulated population under variable conditions with uncertain data. In the no‐harvest case the data consist simply of a temporal sequence of relative population sizes. Dynamic response analysis is most sensitive to the number and precision of the population estimates and least sensitive to environmental variability and the intrinsic population growth rate. Significance levels must be chosen carefully, since some combinations of parameters and error levels result in an unacceptably low proportion of correct assessments. Dynamic response analysis can be a useful stock assessment technique for the management of marine mammals, but attention must be paid to the quantity and quality of the data.
SURVIVORSHIP PATTERNS IN THREE SPECIES OF CAPTIVE CETACEANS
Authors: DeMaster Douglas P. , Drevenak Jeannie K.
Published: August 2006

Abstract

Survival rates for three species of captive cetaceans are reported, based on records of dates of capture, birth, and death of individual animals. The annual survival rate was 0.93 for bottlenose dolphins and killer whales and 0.94 for white whales. Confidence limits of these estimates are discussed. Differences in survival rates between institutions were significant for bottlenose dolphins only. Calf survival for bottlenose dolphins was lower than non‐calf survival. Survivorship of male killer whales was significantly less than survivorship of female killer whales; sex‐specific survival rates were similar for the other two species. Estimates of average or maximum longevity alone were not useful in comparing rates of survival. Because survival in the first year of captivity may be lower than subsequent years, estimates of the expected lifespan, based on data from the first few years of captivity, may be biased.
MANAGING THE EXPLOITATION OF PACIFIC WALRUSES: A TRAGEDY OF DELAYED RESPONSE AND POOR COMMUNICATION1
Authors: Fay Francis H. , Kelly Brendan P. , Sease John L.
Published: August 2006

The Pacific walrus population has been depleted and subsequently allowed to recover three times in the past 150 yr. As we see it, the population has been made to fluctuate like an r‐selected species, rather than being maintained at a high, stable level, as befits a K‐selected species. The latest depletion began in the 1930s but was not recognized until 25 yr later, by which time the population had been reduced by at least half. Without benefit of communication, the U.S.S.R. and the State of Alaska put similar protective measures into place by 1960, and in the next two decades the walrus population recovered again, at least doubling in size. By 1980, it already was showing density‐dependent signs of having approached or reached the carrying capacity of its environment. As productivity and calf survival declined sharply in the late 1970s and early 1980s the catches more than doubled. We believe that the combined effects of natural curtailment and human intervention may be bringing the population down again rather rapidly. With the present, crude monitoring methods, delayed management responses, and poor international communications, however, the downward trend may not be acknowledged for at least another decade, by which time the unilateral Soviet and American corrective measures are likely to be too much, too late. Walrus management needs to be based less on response to immediate crisis and more on long term prediction than it has been in the past. Because the U.S.A. and U.S.S.R. are trying to manage the same walrus population, without sufficient communication or consensus and sometimes to opposite ends, an international joint management program needs to be implemented.
NORTH PACIFIC HUMPBACK WHALE SONGS: A COMPARISON OF SOUTHEAST ALASKAN FEEDING GROUND SONGS WITH HAWAIIAN WINTERING GROUND SONGS
Authors: McSweeney D. J. , Chu K. C. , Dolphin W. F. , Guinee L. N.
Published: August 2006

Abstract

Humpback whales sing long, complex songs on their wintering grounds. On 25 August 1979 and 3 September 1981, we made recordings of humpback whale songs in southeastern Alaska, showing that humpback whales also sing on the summer feeding grounds. Both these Alaskan samples are songs in that they are repeating cyclical sound patterns and follow the known structure for humpback whale song. The Alaskan songs contain all the same material sung in the same order as that heard off Mexico and Hawaii in the surrounding wintering seasons. However, song, theme and some phrase durations are abbreviated in the Alaskan songs. The recording of these two songs represents the full sample of song recorded from 155 days over five years of attempting to record humpback whale song in Alaskan waters.
THE DISTRIBUTION, ABUNDANCE AND SELECTED PREY OF THE HARBOR SEAL,PHOCA VITULINA CONCOLOR, IN SOUTHERN NEW ENGLAND
Authors: Payne P. Michael , Selzer Lawrence A.
Published: August 2006

Abstract

The seasonal distribution and abundance of harbor seals occurring south of Maine were documented by counting the number of seals at traditional haulout locations. The average number of seals counted during each survey in Massachusetts and New Hampshire was 3,560 ± 255 (95% CI), 1983–1987. The maximum number of seals counted on any individual survey was 4,736 individuals. Fifty percent of all the surveys since January 1985 have resulted in counts greater than 4,000 seals reflecting a 27% increase in the abundance of seals in our study area since that date. Seventy‐five percent of the seals in southern New England are located at haulout sites on Cape Cod and Nantucket Island. The largest aggregation of seals in the eastern United States occurs mid‐winter at Monomoy Island and adjacent shoals. A single high count of 1,672 seals occurred at this site during the study period. An additional 271–374 seals were also counted in Rhode Island, Connecticut and eastern Long Island Sound during surveys conducted in March 1986 and 1987.

The American sandlanceAmmodytes americanuswas the single dominant prey item of harbor seals in waters adjacent to Cape Cod based on the modified frequency of occurrence of each prey species in scat samples collected from three haulout sites on Cape Cod between 1984–1987. During January and February sandlance was the near exclusive prey item at Monomoy (99%,n= 80). During March and April, the frequency of Atlantic herringClupea harengusincreased in the scat samples at this site. Regional differences in the diet of seals reflect distinct prey communities throughout the study area. Since 1986, the percent occurrence and importance of sandlance in the diet of seals has decreased, reflecting an overall decrease in abundance of this prey species in waters adjacent to Cape Cod. In spite of fluctuations in abundance, and regional differences in the diet of seals throughout the study area, sandlance still comprised a minimum 55% of the total prey species of harbor seals throughout the study area.
SEX DETERMINATION OF THE CALIFORNIA SEA LION (ZALOPHUS CALIFORNIANUS CALIFORNIANUS) FROM CANINE TEETH
Authors: Lowry Mark S. , Folk Roberta L.
Published: August 2006

Abstract

Size of canine teeth from California sea lion (Zalophus californianus californianus) carcasses is shown to be useful in determining the sex of animals which have missing genitalia or which are otherwise of unknown sex. A total of 267 canine teeth from carcasses of 68 males and 43 females were measured along five axes. Of root and crown measurements of upper and lower canines, males and females overlapped only in root thickness of upper canines. A multivariate ANOVA showed a significant difference in the size of canines between upper and lower canines, and between males and females. Stepwise discriminant analysis produced discriminant functions for upper and lower canines for determining sex of unknown‐sexed California sea lions. A separate set of canine teeth from 39 male and 49 female California sea lions was correctly classified without prior knowledge of sex by visual inspection and by the two discriminant functions.
TOOTH WEIGHTS OF JUVENILE MALE NORTHERN FUR SEALS, CALLORHINUS URSINUS
Authors: Baker Jason D. , Fowler Charles W.
Published: August 2006

Abstract

Tooth weight and body length of juvenile male northern fur seals, Callorhinus ursinus, collected on St. Paul Island, Alaska, from 1948 to 1984 were compared. The relationship between these variables was investigated for individual and combined age classes. A density‐dependent increase in mean tooth weight occurred during a decline in fur seal abundance. Consistent, though poorly understood, differences in tooth weight were found among males associated with different rookeries (breeding grounds). Storing the teeth for long periods may affect the weights, but such effects, if any, are too small to account for the changes observed.
FATTY ACID COMPOSITION OF FATS FROM THE URUGUAYAN FUR SEAL (ARCTOCEPHALUS AUSTRALIS ZIMMERMANN)
Authors: Grompone Maria A. , Sienra B. , Quilez J. L.
Published: August 2006

Abstract

The composition and properties of commercial oil collected from Uruguayan fur seals (Arctocephalus australis Zimmermann) during 1985, 1986 and 1987 are reported. Oil recovered from some organs (kidney, heart, liver) and blubber were also analyzed. All have compositions similar to oils from other marine animals in commercial use, containing high percentages of long chain and polyunsaturated fatty acids.
A MORPHOLOGICAL CONSIDERATION OF THE RELATIONSHIPS OF PINNIPEDS TO OTHER CARNIVORANS BASED ON THE BONY TENTORIUM AND BONY FALX
Authors: Nojima Takao
Published: August 2006

abstract

The close relationships of pinnipeds to other carnivorans were studied based on morphological characteristics of the bony tentorium (BT) and bony falx (BF) of carnivorans. It appears to be an important characteristic of the Carnivora that the clear BT is present in almost all species including pinnipeds. The BF is present in all species of pinnipeds, and only in the genus Ursus among fissipeds observed.

The parietal bone of all otariids and odobenids observed shows an extremely characteristic form as compared with other carnivorans. The sagittal and squa‐mous borders of the parietal bone of these groups are bridged by a thin bony plate which forms large portions of the BT and BF. In phocids, the aspects of the BT and BF vary among species, but are apparently distinct from those of otariids and odobenids.

The BT of carnivorans can be divided into four types which appear to be useful for classification of the Carnivora. On the basis of the BT and BF form, the Otariidae and Odobenidae appear to have a specific sister relationship to the Ursidae, while the Phocidae appears to have dose affinities to the Mustelidae. Morphological differences of the BT and BF among pinnipeds strongly support the diphyletic origin of pinnipeds.
BLUE WHALE (BALAENOPTERA MUSCULUS)DISTRIBUTION IN THE EASTERN TROPICAL PACIFIC
Authors: Reilly Stephen B. , Thayer Victoria G.
Published: August 2006

Abstract

The distribution of blue whales, Balaenoptera musculus, in the eastern tropical Pacific (ETP) was analyzed from 211 sightings of 355 whales recorded during research vessel sighting surveys or by biologists aboard fishing vessels. Over 90% of the sightings were made in just two areas: along Baja California, and in the vicinity of the Costa Rica Dome (a large, stationary eddy centered near 9°N, 89°W), with the rest made along the equator near the Galapagos islands, the coasts of Ecuador and northern Peru. All sightings occurred in relatively cool, upwelling‐modified waters. Because these areas are the most productive parts of the ETP, and have relatively large standing stocks of euphausiids, it seems possible that blue whales select low latitude habitats which permit foraging. The waters off western Baja California were occupied seasonally, with a peak in sightings coinciding with the spring peak in upwelling and biological production. The Costa Rica Dome area was occupied year round, suggesting either a resident population, or that both northern and southern hemisphere whales visit, with temporal overlap. The modal group size was one for all areas and seasons, but the frequency of groups with two or more whales was significantly higher in sightings made near the Galapagos Islands and the coast of Ecuador and northern Peru.
DENSITY DEPENDENT GROWTH IN NORTH PACIFIC SPERM WHALES
Authors: Kasuya Toshio
Published: August 2006

Abstract

Data from the North Pacific sperm whale (Physeter catodon Linnaeus, 1758) fishery were examined for a possible density dependent change in growth during 40 yr harvesting after World War II. Early in this period males from the eastern stock were 16.8 m or less in length. By the early 1970s the largest males in the catch exceeded 16.8 m in length and reached 18.9 m in the late 1970s. The proportion of males measuring over 16.8 m, among sexually mature males (≥14.0 m), increased from 0 to >20% during the 1970s. Increases in the maximum size of males were possibly preceded by a change in the frequency distribution of body lengths in the middle 1960s when only 10% of the postwar catch had been taken. Testis weights suggested an increase in body length at sexual maturity. Two of the three putative North Pacific stocks showed similar growth changes. Adult males taken in the Bering Sea did not show such changes during the exploitation which ended in 1972 because of overfishing. Females showed no detectable change in body size. It is concluded that: (1) density dependent effects on male growth are greater before sexual maturity than after it, (2) males may show density dependent changes even at a population level above 90% of the carrying capacity, (3) polygynous males acquire more mates and realize higher reproductive success because of increased body size, and (4) females appear to maximize production by maturing earlier and shortening calving intervals in response to density change.
ACOUSTIC REFLECTIVITY OF NETS: IMPLICATIONS CONCERNING INCIDENTAL TAKE OF DOLPHINS
Authors: Au WhitlowW. L. , Jones Linda
Published: August 2006

Abstract

Sonar target strength measurements of several types of nets and associated gear were made using simulated dolphin echolocation signals. The different types of nets included (a) standard commercial monofilament gillnet used in the salmon mothership fishery, (b) prototype hollow core monofilament net, (c) Macah tribal cord setnet, and (d) multifilament nets. Target strength measurements were made at four angles of incidence, 0° (normal to net), 15°, 30°, and 45°. The standard gillnet had the smallest target strength which was relatively independent of the angle of incidence. The target strength based on the peak‐to‐peak values of the echoes varied from –59 to – 62 dB. Using echo energy within the integration time of Tursiops truncatus, the target strength was found to be between – 54 and –59 dB. Biosonar detection ranges for different sea state conditions were estimated using the noise‐limited form of the sonar equation and target detection data obtained for Tursiops truncatus in Kaneohe Bay, Oahu, Hawaii. The results suggest that an echolocating dolphin should be able to detect a gillnet at ranges long enough to avoid entanglement, even in sea state 6 conditions. Several possibilities for the seeming inability of dolphins to detect gillnets are discussed.
MODIFYING GILLNETS TO REDUCE ENTANGLEMENT OF CETACEANS
Authors: Dawson Stephen M.
Published: August 2006

Abstract

To reduce the number of cetaceans caught incidentally in gillnets, two forms of acoustic modifications have previously been proposed. These modifications seek to make gillnets more obvious to cetaceans so they can avoid them, and include making gillnets more reflective to cetacean sonar and placing active sound emitters in the nets. I discuss the relationship between sonar and net entanglement, and address the assumptions and logic of net modification strategies. I argue that neither strategy is likely to be effective, and that reductions in the number of cetaceans killed in gillnets are best achieved through the closure of specific areas to gillnetting.
HYDROSTASIS IN THE SIRENIA: QUANTITATIVE DATA and FUNCTIONAL INTERPRETATIONS
Authors: Domning Daryl P. , de Buffrénil Vivian
Published: August 2006

ABTRACT

It has long been assumed that the heavy bones and horizontal lungs of sirenians are adaptations for maintaining neutral buoyancy and horizontal trim. These assumptions are examined in the light of detailed measurements of skeletal weight distribution in the Florida manatee (Trichechus manatus latirostris), measurements of the positions of body and skeletal centers of gravity in the Amazonian manatee (T. inunguis), and available data on lung morphology in sirenians. The detailed arrangement of bones, muscle masses, and viscera in a sirenian (T. inunguis) is illustrated in cross sections for the first time. The hypotheses that skeletal weight is appropriately distributed to serve as hydrostatic ballast, and that the lungs are properly designed to help maintain horizontal trim, are confirmed. We suggest that selection for maintenance of trim and maximization of turning moments of the flippers may help account, respectively, for hindlimb loss and shortening of the neck in both sirenians and cetaceans. We recommend that the term “pachyostosis” be used to refer only to thickening of bones regardless of their density; that “osteosclerosis” be used for the replacement of cancellous with compact bone; and that “pachyosteosclerosis” be used for the joint occurrence of these conditions. Pachyosteosclerosis in sirenians, which may be brought about during ontogeny by mechanisms involving thyroid and parathyroid hormones, is fully normal and adaptive in this order and in no sense “pathological.”
A NEW SPECIES OF BEAKED WHALE MESOPLODON PERUVIANUS SP. N. (CETACEA: ZIPHIIDAE) FROM PERU
Authors: Reyes Julio C. , Mead James G. , Waerebeek Koen Van
Published: August 2006

Abstract

Mesoplodon peruvianus, a new species of beaked whale, is described on the basis of ten specimens which have either stranded or been captured between 11°12′S and 15°19′S latitude along the coasts of the provinces of Lima and Ica, south central Peru. This is the thirteenth living species of Mesoplodon recognized in the world's oceans. The animals that were examined were uniformly gray above, shading to lighter gray below. This whale is the smallest species of Mesoplodon (maximum body length 3.72 m) and is characterized by its teeth, which are small (31 to 65 mm long), ovate in cross section, and positioned 2.5% to 8.4% of the mandibular length from the anterior extremity, and posterior to the mandibular symphysis.
ACCURACY OF AGE DETERMINATION IN THE GREY SEAL HALICHOERUS GRYPUS OF EASTERN CANADA
Authors: Mansfield A. W.
Published: August 2006

Abstract

The ages of 82 grey seals of known age from 1 to 10 yr were determined from growth layer groups in the cementum, readily seen in longitudinal sections 150 μm thick viewed under transmitted light. The sample of teeth was read five times in a series of blind replicates.

With only one reading, an accuracy of 84% was achieved. This increased to 93% on the basis of three readings but improved only marginally to 94% when all five readings were considered. Accuracy was best in the middle range of ages (3–6 yr) which are the critical years for estimating age‐specific reproductive rates in population models.
CUTANEOUS RIDGES IN ODONTOCETES
Authors: Shoemaker P. A. , Ridgway S. H.
Published: August 2006

Abstract

Cutaneous ridges are present at the surface of the skin in many odontocetes, and although often quite faint, may be observed with the naked eye. We have taken surface impressions and measured the ridges of individuals of seven odontocete species, and observed cutaneous ridges on three additional species. In the delphinids and the one Physeter neonate studied, spatial periods of the ridges varied from 0.4 mm–1.7 mm and trough‐to‐peak heights from less rhan 10μm to about 60μm. Two Delphinapterus (monodontids) had ridges significantly larger than the Physeter and most delphinids, with spatial periods of 1.9–2.4 mm and heights 80–120 μm. We found the ridges distributed over much of the surface of the body, but relatively faint or absent on most of the head, the control surfaces, and the ventral region in some species. In all of the animals we observed, the ridges ran in an approximately circumferential direction around the body trunk rostral to the dorsal fin or mid‐body area, but varied somewhat in direction in the caudal region and in other isolated areas. While the function of the cutaneous ridges has not been established, we speculate that they may play some role in tactile sensing, in the hydrodynamic characteristics of an animal, or both.
PRECISE BIRTH TIMING IN CAPTIVE HARBOR SEALS (PHOCA VITULINA) AND CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS)
Authors: Temte Jonathan L.
Published: August 2006

Abstract

The absolute and relative precision of birth timing was assessed in 27 captive harbor seals and 30 captive California sea lions. Data were obtained from zoos and aquaria and only adult females with at least three live births were selected for analysis. Individuals of both species demonstrated very high absolute precision with narrow ranges of birth dates and small standard deviations of the individual mean birth dates. In addition, with the exception of one sea lion, no temporal trends for earlier or later birthing were found. Whereas marked differences in birth timing were found among individual harbor seals, these relative differences tended to disappear when subspecies affiliation and location were taken into account. Moderate inter‐individual differences were also found among the California sea lions, but these differences persisted following the partitioning of adult females by location.

The absolute precision in birth timing strongly suggests that environmental regulation of birth timing occurs via a highly precise cue, such as photoperiod. The relative differences among individuals may indicate that birth timing in pinnipeds has a heritable component, and hence may evolve in response to natural selection, thus allowing adaptation of the pupping season to specific seasonal environments.
DISTRIBUTION PATTERNS OF INDIVIDUALLY IDENTIFIABLE WEST INDIAN MANATEES (TRICHECHUS MANATUS) IN FLORIDA
Authors: Reid JamesP. , Rathbun Galen B. , Wilcox J. Ross
Published: August 2006

Abstract

Photographs of distinctively scarred manatees (Trichechus manatus) were taken at aggregation sites throughout Florida and assembled into a catalog for identifying individuals. Resightings of known manatees in different years or at different locations enabled us to document site fidelity and long‐distance movements. Of the 891 individuals included in the catalog as of August 1986, 470 (53%) were resighted at least once. We documented 219 cases of seasonal returns to specific aggregation sites and 98 instances of movements between areas. Movements in excess of 820 km were documented for individuals on the east coast of Florida. Rapid movements south during early winter, as well as northerly spring movements, verify a seasonal migration pattern for many individuals along Florida's east coast. The wide‐ranging migratory habits of manatees in Florida must be considered if meaningful management strategies are to be developed and implemented.
THE OCULAR SECRETIONS OF THE BOTTLENOSE DOLPHINTURSIOPS TRUNCATUS
Authors: Young N. M. , Dawson W. W.
Published: August 2006

Abstract

A viscous ocular secretion streams from the eyes of bottlenose dolphins,Tursiops truncatuss, removed from the water. The chemical composition and environmentally adaptive implications of this substance continue to perplex curators and scientists. Secretions from three dolphins were examined for deviations from literature values for normal human and terrestrial mammalian tear film components. Osmolality (x̄= 470 mOsm/kg), pH (x̄= 8.44) and glucose (x̄= 26.58 mg/100 ml) were significantly greater than human and terrestrial mammalian tear film values; while lysozyme (x̄= 0.005 mg/ml) and total cholesterol (x̄= 0.17 μg/μ1) were significantly less. Refractive index, sodium ion concentration, and potassium tear to plasma ratios in the dolphin ocular secretion did not deviate significantly from human or terrestrial mammalian tears. Electrophoresis of dolphin tears yielded four major protein bands (probably lactoferrin, serum albumin, teat specific prealbumin, and lysozyme) and high molecular weight glycoproteins similar to human tears. The chemical composition of theT. truncatusocular secretion suggests that the circumorbital conjunctival gland may be analogous (relative to refractive index, electrolytes, and component protein) to the terrestrial lachrymal gland. At the functional level theT. truncatusocular secretion may reduce hydrodynamic resistance on the cornea and protect it from bacterial invasion.
ANALYSIS OF SWIM VELOCITIES DURING DEEP AND SHALLOW DIVES OF TWO NORTHERN FUR SEALS, CALLORHINUS URSINUS
Authors: Ponganis Paul J. , Gentry Roger L. , Ponganis Edward P. , Ponganis Katherine V.
Published: August 2006

Abstract

Swim velocities at 15‐sec intervals and maximum depth per dive were recorded by microprocessor units on two “mixed diver” adult female northern fur seals during summer foraging trips. These records allowed comparison of swim velocities of deep (>75 m) and shallow (<75 m) dives.

Deep dives averaged 120 m depth and 3 min duration; shallow dives averaged 30 m and 1.2 min. Mean swim velocities on deep dives were 1.8 and 1.5 m/sec for the two animals; mean swim velocities on shallow dives were 1.5 and 1.2 m/sec. The number of minutes per hour spent diving during the deep and shallow dive patterns were 11 and 27 min, respectively.

Swim velocity, and hence, relative metabolic rate, did not account for the differences in dive durations between deep and shallow dives. The long surface durations associated with deep dives, and estimates of metabolic rates for the observed swim velocities, suggest that deep dives involve significant anaerobic metabolism.
THERMAL INFRARED RADIATION FROM FREE LIVING WHALES
Authors: Cuyler L. C. , Wiulsrød R. , ØRitsland N. A.
Published: August 2006

As part of a search for new detection techniques, and for obtaining information on whale surface temperatures, an Agema Thermovision 880 thermal imaging system was used to detect thermal infrared radiation from whales. The study took place along the northern coast of Norway and the northwest coast of Svalbard (68° to 80° N latitude). The emphasis of the study was on minke whales, but humpback, fin, blue and sperm whales were also observed. The apparent radiation temperature was strongly dependent on sea conditions, signal angle, and atmospheric interference; detection depended thus upon weather. During the study, sea surface temperatures varied as much as 7°C but the sea and minke whale body trunk surfaces were usually within 0.0° to 0.1°C of each other. The other species observed had temperature differences of 0.0° to 1.0°C relative to the sea surface. Temperature differences between sea water and whale appendages ranged from 0.0° to 6.0°C. The indicated maximum difference between sea water and blow (i.e., expired air) was 4.0°;C, while the maximum difference for the blowhole was 4.1°C. The results from all whales observed support the belief that the main body trunk is normally not a heat window, this function being reserved for the appendages. However, the results also indicate a regulated dermal blood flow determining heat loss from the body trunk. Detection of whales by thermal infrared radiation from the body trunk appears unreliable; in contrast, the blow and blowhole provided a consistent positive signal with apparent temperature differences to the surroundings ranging from 0.2° to 4.1°C.
RANGE‐WIDE SURVEY AND ESTIMATION OF TOTAL NUMBER OF STELLER SEA LIONS IN 1989
Authors: Loughlin Thomas R. , Perlov Adolf S. , Vladimirov Valery A.
Published: August 2006

Abstract: The first range‐wide survey of Steller (northern) sea lions (Eumetopias jubatus) was completed in 1989 with a total of 68,094 adult and juvenile (nonpup) Steller sea lions counted. This total count includes 10,000 in Russia (15% of the range‐wide count), 47,960 in Alaska (70%), 6,109 in British Columbia (9%), 2,261 in Oregon (3%), and 1,764 in California (3%). A range‐wide pup count was not obtained. We estimated the 1989 world population based on a calculation for total pups and obtained a range‐wide estimate of 116,000 total animals, or about 39–48% of the 240,000‐300,000 estimated 30 yr ago.
GEOGRAPHIC VARIATION AND SEXUAL DIMORPHISM IN THE SKULL OF DALL'S PORPOISE, PHOCOENOIDES DALLI
Authors: Amano Masao , Miyazaki Nobuyuki
Published: August 2006

Abstract: Two hundred and eighty‐nine skulls of Dall's porpoises from the North Pacific Ocean, Sea of Japan, Sea of Okhotsk, and Bering Sea were investigated morphometrically. A clear pattern of geographic variation was found in overall size of the skull. In the North Pacific, overall skull size became gradually smaller eastward from the coast of Japan to the offshore eastern Pacific, and it became larger again off the coast of California. Specimens from the Sea of Japan‐Okhotsk and Bering Sea had larger skulls than those from the central North Pacific. The distribution of primary productivity corresponds well with this pattern of geographic variation, suggesting that quantity of food might affect the overall size of Dall's porpoise skulls. By canonical discriminant analyses, about 70% (male) and 90% (female) of specimens of the Sea of Japan‐Okhotsk population were distinguished from those of other populations. This agrees with the results of genetic studies.
MORTALITY OF SEA OTTERS IN PRINCE WILLIAM SOUND FOLLOWING THE EXXON VALDEZ OIL SPILL
Authors: Garrott Robert A. , Eberhardt L. Lee , Burn Douglas M.
Published: August 2006

Abstract: This paper presents an estimate of the total number of sea otters that died as a direct consequence of the oil spill that occurred when the T/V Exxon Valdez grounded in Prince William Sound, Alaska on 24 March 1989. We compared sea otter counts conducted from small boats throughout the Sound during the summers of 1984 and 1985 to counts made after the spill during the summer of 1989. We used ratio estimators, corrected for sighting probability, to calculate otter densities and population estimates for portions of the Sound affected by the oil spill. We estimated the otter population in the portion of Prince William Sound affected by the oil was 6,546 at the time of the spill and that the post‐spill population in the summer of 1989 was 3,898, yielding a loss estimate of approximately 2,650. Bootstrapping techniques were used to approximate confidence limits on the loss estimate of about 500–5,000 otters. The wide confidence limits are a result of the complex scheme required to estimate losses and limitations of the data. Despite the uncertainty of the loss estimate it is clear that a significant fraction of the otters in the spill zone survived. We observed otters persisting in relatively clean embayments throughout the oil spill zone suggesting that the highly convoluted coastline of Prince William Sound produced refuges that allowed some sea otters in the oil spill area to survive.
THE SOUTHERN SEA LION, OTARIA BYRONIA OR OTARIA FLAVESCENS?
Authors: Rodriguez Diego H. , Bastida Ricardo O.
Published: August 2006

Abstract: The status of the specific name of the Southern sea lion is controversial; currently two names are in use: Otaria flavescens (Shaw, 1800) and Otaria byronia (de Blainville, 1820). The former was based on a two‐foot‐long yellowish otariid collected in the Strait of Magellan and the latter on a skull stated to have been collected on the Tinian Island (Marianas Archipelago); unfortunately both holotypes are lost. Otaria flavescens has date priority over Otaria byronia, but its identification was uncertain. This paper focuses on analyzing the main features of Shaw's holotype (body length, ear size, and hair color), which fit with the features of a Southern sea lion pup. As this was a tangible specimen from a valid locality and has priority over other available epithets, the specific name of the Southern sea lion should be Otaria flavescens (Shaw, 1800).
AGE, GROWTH, AND REPRODUCTION OF THE FINLESS PORPOISE, NEOPHOCAENA PHOCAENOIDES, IN THE COASTAL WATERS OF WESTERN KYUSHU, JAPAN
Authors: Shirakihara Miki , Takemura Akira , Shirakihara Kunio
Published: August 2006

Abstract: In the coastal waters of western Kyushu, Japan, a total of 97 incidentally taken or stranded finless porpoises, Neophocaena phocaenoides, was collected for studying age, growth and reproduction. An additional 17 specimens from the Inland Sea were used for a comparison of life history. Mean neonatal body length was 78.2 cm. Both males and females grew to around 140 cm by 5 yr of age. The maximum body lengths of males and females in western Kyushu were 174.5 cm and 165.0 cm, respectively, which were smaller than those recorded in other Japanese waters. Females probably attain sexual maturity at ages of 6–9 yr and at body lengths of 135–145 cm. Males probably mature sexually at ages of 4–6 yr, at body lengths of 135–140 cm and at weight of testis of 40–150 g. The lack of females aged 5–6 yr and males aged 4–5 yr precluded firm conclusions on ages at sexual maturity. Parturition in western Kyushu was estimated to be prolonged from autumn to spring, whereas in the Inland Sea and Pacific waters it was restricted from spring to summer with a peak in April. These geographical differences and available information on distribution implies that the finless porpoises in western Kyushu constitute a local population.
BODY WEIGHT and GROWTH OF JUVENILE MALE NORTHERN FUR SEALS, CALLORHINUS URSINUS
Authors: Baker Jason D. , Fowler Charles W. , Antonelis George A.
Published: August 2006

Abstract

A mark‐recapture study conducted in 1987–1992 provided weight measurements of juvenile male northern fur seals (Callorhinus ursinus) on St. Paul Island, Alaska, at ages ranging from approximately 1.5 mo to 5 yr. Males born in 1987 tended to weigh less at ages 3 and 4 yr than those born in other years. Weights of individuals at ages 2, 3, and 4 yr were significantly correlated with their weights as pups (P < 0.05). Weights at ages 2 and 3, 3 and 4, and 4 and 5 yr were significantly correlated (P < 0.001), although weight changes with age were highly variable. Data indicate that larger than average male pups born during 1987–1990 were more likely to survive, but this effect was less evident than among pups born during 1960–1965 when average pup weights were lower.
OBSERVATIONS OF FLORIDA MANATEES(TRICHECHUS MANATUS LATIROSTRIS) AROUND SELECTED POWER PLANTS IN WINTER
Authors: Reynolds John E. , Wilcox J. Ross
Published: August 2006

Abstract

Sixty‐four aerial surveys were flown during cold, winter weather between December 1982 and February 1772 to provide an index of trends in abundance of the Florida manatee (Trichechus manatus latirostris)around five Florida Power & Light Company (FPL) plants. The surveys documented high winter use of warm‐water discharges at four of the plants (Canaveral, Riviera. Port Everglades, and Fort Myers). The total number of manatees sighted at the five primary plants surveyed during a single survey ranged from 6 to 765 manatees (x̄= 330 ± 45 manatees per survey): thus, up to 41% of the total Florida manatee minimum population of 1.850 animals may be found on cold days at FPL plants. The number of calves sighted at the plants during winter has decreased; similarly, for three consecutive years (winter 1989–1970 through winter 1991–1992), the percentage of the manatees that are calves sighted at the plants has decreased. Although data from the surveys of FPL plants do not necessarily reflect what may be happening with manatees located elsewhere in Florida, a possible reduction in calf numbers, coupled with increasing numbers of dead calves being documented by scientists involved in manatee carcass salvage work, is cause for concern in this slow‐reproducing, endangered species.
CROSS‐REACTIVITY OF ANTIBODIES TO HUMAN ANTIGENS WITH TISSUES OF THE BOTTLENOSE DOLPHIN, TURSIOPS TRUNCATUS, USING IMMUNOPEROXIDASE TECHNIQUES
Authors: Kumar Dhruv , Cowan Daniel F.
Published: August 2006

Abstract

Cross‐species reactivity of 53 antibodies developed against human antigens was evaluated in the bottlenose dolphin Tursiops truncatus, using immunoperoxidase techniques, Strong cross‐reactivity was demonstrated with antibodies against intermediate filaments, most hormones, but few leukocyte antigens. S100, NSE, F8RA, Factor XIIIa, and lactalbumin antibodies reacted, while HMB45, EMA, PLAP, and PSA did not. Polyclonal antibodies are much more likely to cross‐react than are monoclonal antibodies. Twenty‐four of 30 (80%) of polyclonals cross‐reacted, while only 10 of 23 (43.5%) monoclonals cross‐reacted. Some antigens are demonstrated only after using a special technique to unmask the antigen.