摘要:

Abstract:Bioelectrical impedance analysis (BIA) measures resistance and reactance of a current as it passes through an organism. The validity of using BIA as a tool to measure body water content, and hence body composition and condition, was tested on harp and ringed seals. The resistance and reactance readings from BIA were compared to estimates of total body water (TBW) determinedviatritiated water dilution. The relationship between resistance and TBW (% of body mass) was linear after logarithmic transformation and the two variables were highly correlated. We describe the electrode configuration and placements which provide reliable results in these seals. Our findings indicate that BIA has considerable potential as an inexpensive, rapid, and reliable technique for estimating body composition of phocid seals.

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00385.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract:The annual reproductive cycle is described for the adult female Hawaiian monk seal (Monachus schauinslandi) from data collected at Laysan Island (1982–1991) and Lisianski Island (1982–1983) in the Northwestern Hawaiian Islands. Pupping, lactation, weaning, and molting were directly observed, while mating was rarely observed and was, therefore, inferred from the occurrence of mounting injuries and from adult male and female association patterns. Pooled birth rates during the study period were 0.544 for all adult‐sized females and 0.675 for females parous in earlier years. For parturient females, pupping peaked in late March and early April, weaning in May, mounting injuries in May and June, and molting in July. For non‐parturient females, the median mounting injury and molting dates occurred 17 and 28 days earlier, respectively. Pupping date set the timing of subsequent events in the annual cycle, but the timing of those events was adjusted by loss of the pup or poor physical condition of the female. Individual pupping patterns varied widely. The mean interval for births in consecutive years was 381 days; females that pupped in consecutive years gave birth later each season. Conversely, females who skipped a year or more gave birth earlier their next pupping

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00386.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract:Sea otters may give birth in any month of the year, so obtaining reproductive rates by observation is difficult. Reproductive rates may be estimated directly (births per otter‐year observed) or by determining the time interval between births. Both methods give the same result for long sequences of observations, but field data are limited to shorter periods. Monte Carlo simulations were conducted to compare the two approaches, and showed that the interval method overestimates true reproductive rate

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00387.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract:Populations of northern sea lions (Eumetopias jubatus) in the vicinity of Marmot Island, Alaska declined during 1975–1985 at about 5% per year (Merricket al.1987). The cause of this decline is not known. A life table for the northern sea lion was calculated assuming that life spans follow a Weibull distribution. Samples of northern sea lions taken in the vicinity of Marmot Island, Alaska during 1975–1978 and 1985–1986 indicate that the average age of females older than 3 yr increased about 1.55 yr (SD = 0.35 yr) while the population was declining at about 5% per year. Fecundity rates decreased by 10% over the same period, but the decrease was not statistically significant (Calkins and Goodwin 1988). Possible causes of the population decline and the change in age structure were examined by writing the Leslie matrix population equation in terms of changes in juvenile and adult survival rates and fecundity, and examining the short–term behavior of the trajectories of the average age of adult females, total number of females, and total number of pups with respect to those changes in the vital parameters. From the observed rate of declines of adults and the changes in average age of adult females and fecundity, estimates of the changes in adult and juvenile survival were calculated; estimates of the standard deviations of these changes were estimatedviaa bootstrap procedure. One purpose of this exercise is to aid in setting priorities for research for determining the cause of the decline. An explanation for the observed declines in numbers of adult sea lions consistent with the observed fecundity rates, a rate of decrease of 5% in the number of adults, and the corresponding increase in average age (of females age 3 yr and older) was a 10%–20% decrease in the survival of juveniles (age 0‐3 yr) coupled with an insignificant change in adult survival (0.03

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00388.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract:An epithelial cell line, Carvan dolphin kidney (CDK), isolated from a prematurely born female bottlenose dolphin,Tursiops truncatus, exhibited growth characteristics not previously reported for cetacean cells in culture. CDK cells were cytokeratin positive and demonstrated a maximum doubling time of 1.31 days, with plating and colony forming efficiencies approaching 100% for the early population doublings. Despite an unusually efficient colony‐forming ability and rapid growth, these cells were neither transformed nor immortal, displaying normal contact inhibition, anchorage dependence, and the requirement for high concentrations of fetal bovine serum in the growth medium. CDK cells exhibited age‐dependent changes in growth rate, colony‐forming efficiency, and cytoplasmic profile, and showed a finite lifespan of about 50 population doublings and a stable 2N = 44 karyotype which correlates with previously reported cytogenetic analyses. Velocity sedimentation analysis showed that CDK cells contained nuclear aryl hydrocarbon receptor (Ah), indicating their potential to be induced for cytochrome P450. These data suggest that CDK cells may have utility as anin vitrotoxicological model for evaluating hydrocarbon contaminant effects onTursiops truncatus, a protected marine m

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00389.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract:Generalization of a rule is demonstrated if the rule governs a class of problem, and the subject, after successful experience with a limited number of problems, can apply the governing rule to new problems within that class. We show that the bottlenose dolphin (Tursiops truncatus) is capable of such generalization for classes of problems requiting the matching of one of two alternative stimuli to a “sample” stimulus to which the animal had been previously exposed, regardless of the sensory domain used: vision, passive listening, or active echolocation. We also show this generalization capability in a related class of problem requiring a judgment of whether a single “probe” stimulus is the same as, or different from, a stimulus or stimuli previously presented. Further, one dolphin was shown capable of developing a true abstract concept of same/different through its ability to categorize pairs ofsimultaneouslypresented objects as identical or not. The suggestion that such generalization ability of dolphins may be in question because of so‐called exclusion effects is shown to be not tenable when the whole body of available data is c

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00390.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00391.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00392.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00393.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1994.tb00394.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY