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Terry R. Spraker - One of the best experts on this subject based on the ideXlab platform.
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digeneans of northern fur seals Callorhinus ursinus pinnipedia otariidae from five subpopulations on st paul island alaska
Parasitology Research, 2018Co-Authors: T A Kuzmina, Terry R. Spraker, E T Lyons, Vasyl V Tkach, Olena KudlaiAbstract:A parasitological survey of 651 northern fur seals Callorhinus ursinus L. from five subpopulations was conducted on St. Paul Island, Alaska, during July–August 2012–2014. Digenean trematodes were found in 210 of 651 fur seals with a total prevalence of 32.3%. Intensity of infection varied from 1 to 1540 parasites with mean intensity 18.4 ± 111.1 SD and median intensity of 2 specimens per host. Significant differences in prevalence and intensity of infection in northern fur seals between separate rookeries was not observed (Mann–Whitney test; p > 0.05). Four species of digeneans belonging to the families Heterophyidae (Apophallus zalophi Price, 1932, Phocitrema fusiforme Goto and Ozaki, 1930, and Galactosomum ubelakeri (Dailey, 1969)) and Troglotrematidae (Nanophyetus salmincola (Chapin, 1926)) were found. Nanophyetus salmincola is reported from C. ursinus for the first time. We obtained partial 28S rDNA sequences for all digenean species and conducted molecular phylogenetic analysis to demonstrate their phylogenetic relationships.
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the cestode community in northern fur seals Callorhinus ursinus on st paul island alaska
International journal for parasitology. Parasites and wildlife, 2015Co-Authors: T A Kuzmina, Terry R. Spraker, E T Lyons, Jesus S Hernandezorts, Vadym V Kornyushyn, Roman KuchtaAbstract:The diversity and ecology of cestodes from the northern fur seals, Callorhinus ursinus (NFS), were examined using newly collected material from 756 humanely harvested subadult males between 2011 and 2014. NFSs were collected from five different haul-outs on St. Paul Island, Alaska. A total of 14,660 tapeworms were collected with a prevalence of 98.5% and intensity up to 107 cestodes per host (mean intensity 19.7 ± 16.5 SD). Three species of tapeworms were found: Adenocephalus pacificus (Diphyllobothriidea) was the most prevalent (prevalence 97.4%), followed by Diplogonoporus tetrapterus (49.7%), and 5 immature specimens of Anophryocephalus cf. ochotensis (Tetrabothriidea) (0.5%). Most of the cestodes found in the NFS were immature (69.7%). However, only 0.9% of cestodes were in larval (plerocercoid) stages. The species composition, prevalence and intensity of cestodes from these NFSs were not statistically different between the five separate haul-outs. Significant increases in the intensity of NFS infections were observed during the study period.
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bilaterally symmetrical lesions of the caudate nucleus in a northern fur seal pup Callorhinus ursinus
Veterinary Record Case Reports, 2015Co-Authors: Vanessa Fravel, William Van Bonn, Sophie Dennison, Terry R. SprakerAbstract:A northern fur seal ( Callorhinus ursinus ) pup was stranded and brought to The Marine Mammal Center (TMMC) in Sausalito, California, USA, for rehabilitation. Upon admission, the animal was lethargic, underweight and ataxic. Clinical diagnostics, including complete blood cell count (CBC), serum chemistry, protozoal antibody titres, radiographs and cisterna magna ultrasonography, were completed and considered within normal limits. MRI of the brain revealed bilaterally symmetrical focal lesions of the rostrolateral caudate nucleus. Treatment for thiamine deficiency and immune-mediated disease was initiated, but the pup did not improve. The pup was euthanased and postmortem examination revealed no gross lesions. Histopathology revealed bilateral regions of oedema, and areas of early malacia, within the caudate nucleus. Although the aetiology is not identified, the distribution of the lesions suggests a toxic insult or could be related to a developmental neurodegenerative disease. This case also gives an insight into the potential role of the caudate nucleus in fur seals.
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novel polyomaviral infection in the placenta of a northern fur seal Callorhinus ursinus on the pribilof islands alaska usa
Journal of Wildlife Diseases, 2013Co-Authors: Colleen Duncan, Tom Gelatt, Tracey Goldstein, Carol Hearne, Terry R. SprakerAbstract:Viruses of the family Polyomaviridae infect a wide variety of avian and mammalian hosts with a broad spectrum of outcomes including asymptomatic infection, acute systemic disease, and tumor induction. In 2010, intranuclear viral inclusion bodies were identified in trophoblasts of a single northern fur seal (NFS; Callorhinus ursinus) placenta from a presumed healthy birth on St. Paul Island, Alaska. On transmission electron microscopy, virions were approximately 40 nm in diameter and were arranged in paracrystal-line arrays within the nucleus. The tissue was positive for the polyomaviral major capsid gene (VP1) by PCR, and the sequenced product revealed a novel Orthopolyomavirus. Twenty-nine additional NFS placentas, devoid of viral inclusions on histologic examination, were tested for polyomavirus by PCR; all were negative. The significance of this novel virus for the infected animal is unknown, but the virus does not appear to be very prevalent within the placentas from newborn northern fur seal pups.
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update on the prevalence of the hookworm uncinaria lucasi in northern fur seals Callorhinus ursinus on st paul island alaska 2011
Parasitology Research, 2012Co-Authors: E T Lyons, T A Kuzmina, S C Tolliver, Terry R. SprakerAbstract:Prevalence of hookworms (Uncinaria lucasi Stiles, 1901) was determined in the northern fur seal (Callorhinus ursinus Linnaeus, 1758) on St. Paul Island (SPI), Alaska in July and August, 2011. Three of 61 (4.9%) dead pups harbored 1 to 13 adult hookworms each in their intestines. Parasitic larvae (L3) of hookworms were recovered from the blubber of 4 of 133 (3%) of subadult males (SAMs) examined. One parasitic L3 was detected from each infected SAM. Adult U. lucasi (n = 3) were found in the intestine of 1 of 105 SAMs examined (0.95%). This is the first documented finding of adult U. lucasi in SAMs of the northern fur seals. Continued low prevalence of hookworms the last several years parallels the tremendous decline in the number of fur seals on SPI over a similar time period.
E T Lyons - One of the best experts on this subject based on the ideXlab platform.
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digeneans of northern fur seals Callorhinus ursinus pinnipedia otariidae from five subpopulations on st paul island alaska
Parasitology Research, 2018Co-Authors: T A Kuzmina, Terry R. Spraker, E T Lyons, Vasyl V Tkach, Olena KudlaiAbstract:A parasitological survey of 651 northern fur seals Callorhinus ursinus L. from five subpopulations was conducted on St. Paul Island, Alaska, during July–August 2012–2014. Digenean trematodes were found in 210 of 651 fur seals with a total prevalence of 32.3%. Intensity of infection varied from 1 to 1540 parasites with mean intensity 18.4 ± 111.1 SD and median intensity of 2 specimens per host. Significant differences in prevalence and intensity of infection in northern fur seals between separate rookeries was not observed (Mann–Whitney test; p > 0.05). Four species of digeneans belonging to the families Heterophyidae (Apophallus zalophi Price, 1932, Phocitrema fusiforme Goto and Ozaki, 1930, and Galactosomum ubelakeri (Dailey, 1969)) and Troglotrematidae (Nanophyetus salmincola (Chapin, 1926)) were found. Nanophyetus salmincola is reported from C. ursinus for the first time. We obtained partial 28S rDNA sequences for all digenean species and conducted molecular phylogenetic analysis to demonstrate their phylogenetic relationships.
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the cestode community in northern fur seals Callorhinus ursinus on st paul island alaska
International journal for parasitology. Parasites and wildlife, 2015Co-Authors: T A Kuzmina, Terry R. Spraker, E T Lyons, Jesus S Hernandezorts, Vadym V Kornyushyn, Roman KuchtaAbstract:The diversity and ecology of cestodes from the northern fur seals, Callorhinus ursinus (NFS), were examined using newly collected material from 756 humanely harvested subadult males between 2011 and 2014. NFSs were collected from five different haul-outs on St. Paul Island, Alaska. A total of 14,660 tapeworms were collected with a prevalence of 98.5% and intensity up to 107 cestodes per host (mean intensity 19.7 ± 16.5 SD). Three species of tapeworms were found: Adenocephalus pacificus (Diphyllobothriidea) was the most prevalent (prevalence 97.4%), followed by Diplogonoporus tetrapterus (49.7%), and 5 immature specimens of Anophryocephalus cf. ochotensis (Tetrabothriidea) (0.5%). Most of the cestodes found in the NFS were immature (69.7%). However, only 0.9% of cestodes were in larval (plerocercoid) stages. The species composition, prevalence and intensity of cestodes from these NFSs were not statistically different between the five separate haul-outs. Significant increases in the intensity of NFS infections were observed during the study period.
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update on the prevalence of the hookworm uncinaria lucasi in northern fur seals Callorhinus ursinus on st paul island alaska 2011
Parasitology Research, 2012Co-Authors: E T Lyons, T A Kuzmina, S C Tolliver, Terry R. SprakerAbstract:Prevalence of hookworms (Uncinaria lucasi Stiles, 1901) was determined in the northern fur seal (Callorhinus ursinus Linnaeus, 1758) on St. Paul Island (SPI), Alaska in July and August, 2011. Three of 61 (4.9%) dead pups harbored 1 to 13 adult hookworms each in their intestines. Parasitic larvae (L3) of hookworms were recovered from the blubber of 4 of 133 (3%) of subadult males (SAMs) examined. One parasitic L3 was detected from each infected SAM. Adult U. lucasi (n = 3) were found in the intestine of 1 of 105 SAMs examined (0.95%). This is the first documented finding of adult U. lucasi in SAMs of the northern fur seals. Continued low prevalence of hookworms the last several years parallels the tremendous decline in the number of fur seals on SPI over a similar time period.
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Hookworms (Uncinaria lucasi) and acanthocephalans (Corynosoma spp. and Bolbosoma spp.) found in dead northern fur seals (Callorhinus ursinus) on St. Paul Island, Alaska in 2007
Parasitology Research, 2008Co-Authors: M. Ionita, T. R. Spraker, E T Lyons, M. G. Varela, S C TolliverAbstract:Intestines of dead northern fur seals ( Callorhinus ursinus ) on St. Paul Island (SPI), Alaska were inspected for specific internal parasites (hookworms and acanthocephalans) in July and August, 2007. Pups ( n = 64) were examined for adult hookworms ( Uncinaria lucasi ) and four (6.25%) were infected. The number of specimens per infected pup was 1, 2, 2, or 408. Low prevalence was similar to that determined in the last investigation (2001) in dead fur seal pups on SPI by two of the present authors (Lyons and Spraker). Subadult males (SAMS—3–4 years old, n = 115) were examined for acanthocephalans and 25 (21.7.0%) were infected. Adult Corynosoma ( C. obtuscens , C. strumosum , and C. validum ) ( n = 56) and immature Bolbosoma spp. ( n = 4) were found. Apparently, this is a new host record for C. obtuscens and C. validum. Notes were made on finding tapeworms. in 114 of the 115 SAMs. Examination of some specimens revealed scolices characteristic of Diphyllobothrium spp.
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historic importance of some aspects of research by o wilford olsen on hookworms uncinaria lucasi in northern fur seals Callorhinus ursinus and steller sea lions eumatopias jubatus in 1951 on st paul island alaska
Parasitology Research, 2005Co-Authors: E T LyonsAbstract:The purpose of this paper is to disseminate, more widely, certain historically important aspects of research by O. Wilford Olsen on hookworms (Uncinaria lucasi) in northern fur seals (Callorhinus ursinus) and Steller sea lions (Eumatopias jubatus) in 1951 on St. Paul Island, Alaska. Highly meaningful facets of the research were recorded only in a report with limited availability by Olsen in 1952. Portions of his research presented here include measurements of hookworm free-living infective third-stage larvae (L3) and adults, photographs of bursae, and the conclusion that the species of hookworms (U. lucasi) is probably the same in both pinniped hosts. This information is especially important because very little has been published on taxonomy of hookworms in E. jubatus.
Stephen J Insley - One of the best experts on this subject based on the ideXlab platform.
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Long-term vocal recognition in the northern fur seal
Nature, 2000Co-Authors: Stephen J InsleyAbstract:The ability to recognize and remember individual identities for long periods of time has important implications for the evolution of animal social behaviour, particularly complex interactions such as cooperation or mate choice. Despite this importance, there is only a single example of long-term individual recognition in nature, the 8-month retention of neighbour's song among male hooded warblers, Wilsonia citrina, and there is none for a non-human mammal. Associations between individuals spanning years, which are especially prevalent in carnivores, primates and seabirds, and evidence of mate fidelity provide indirect support for the ability of long-term recognition. In many of these instances, however, individuals do not separate for extended periods, and thus long-term recognition, although often assumed, may be both unnecessary and nonexistent. Furthermore, site fidelity rather than individual recognition may explain many instances of mate fidelity. Here I show that mother-offspring pairs of a migratory otariid pinniped--the northern fur seal (Callorhinus ursinus)--not only have the ability to recognize each other's vocalizations during the course of a breeding season, but are also able to retain these memories for at least 4 years.
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Long-term vocal recognition in the northern fur seal. (Callorhinus ursinus)
NATURE (LONDON) 406(6794):404-405. 2000., 2000Co-Authors: Stephen J InsleyAbstract:The ability to recognize and remember individual identities for long periods of time has important implications for the evolution of animal social behaviour, particularly complex interactions such as cooperation or mate choice. Despite this importance, there is only a single example of long-term individual recognition in nature, the 8-month retention of neighbour's song among male hooded warblers, Wilsonia citrina, and there is none for a non-human mammal. Associations between individuals spanning years, which are especially prevalent in carnivores, primates and seabirds, and evidence of mate fidelity provide indirect support for the ability of long-term recognition. In many of these instances, however, individuals do not separate for extended periods, and thus long-term recognition, although often assumed, may be both unnecessary and nonexistent. Furthermore, site fidelity rather than individual recognition may explain many instances of mate fidelity. Here I show that mother–offspring pairs of a migratory otariid pinniped—the northern fur seal (Callorhinus ursinus)—not only have the ability to recognize each other's vocalizations during the course of a breeding season, but are also able to retain these memories for at least 4 years.
George A Antonelis - One of the best experts on this subject based on the ideXlab platform.
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otolith size and location in digestive tracts of northern fur seals Callorhinus ursinus implications for dietary interpretations
Marine Mammal Science, 2011Co-Authors: E H Sinclair, Anne E York, George A AntonelisAbstract:Walleye pollock (Theragra chalcogramma) otoliths (n = 2,706) recovered from stomachs, small intestines, and colons of 43 northern fur seals (Callorhinus ursinus) were evaluated for size and wear by location in the digestive tract. Pollock fork length was regressed on otolith length after correction for erosion, and age was estimated from the calculated body size. Age-1+ pollock otoliths (≥6.3-mm length) were concentrated in stomachs while age-0 otoliths (≤6.2-mm length) were concentrated in colons. Less than 10% of otoliths were found in the small intestines. Pollock age decreased with progression along seal gastrointestinal tracts. Otolith quality increased along gastrointestinal tracts in numbers ≥20, which was typical of age-0 otoliths recovered from colons. Otolith distribution by age and quality along gastrointestinal tracts suggests that small (≤12 cm) schooling prey are consumed in large volume and passed as a bolus rapidly through the digestive tract before significant erosion of bony remains occurs; while larger prey are eaten in smaller volume and subjected to otolith erosion due to longer retention in the stomach. Our results illustrate the importance of multiple sampling strategies to comprehensively represent prey size in pinniped diet.
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separation of foraging habitat among breeding sites of a colonial marine predator the northern fur seal Callorhinus ursinus
Canadian Journal of Zoology, 2004Co-Authors: B W Robson, Jason D Baker, George A Antonelis, Rolf R Ream, Michael E Goebel, Thomas R Loughlin, Robert C Francis, Daniel P CostaAbstract:This study examines whether lactating northern fur seals (Callorhinus ursinus) from different breeding sites on the Pribilof Islands in the eastern Bering Sea forage in separate areas. Satellite transmitters were attached to 97 northern fur seal females from nine breeding areas for 119 complete foraging trips during the 1995 and 1996 breeding seasons. Females from St. Paul and St. George islands tended to travel in different directions relative to their breeding site in both years of the study. St. Paul Island females dispersed in all directions except to the southeast, where St. George Island females foraged. Habitat separation was also observed among breeding areas on northeastern and southwestern St. Paul Island and to a lesser degree on northern and southern St. George Island. Although foraging direction led to geographical separation among sites, the maximum distance traveled and the duration of foraging trips did not differ significantly among islands in either year. The results of this study docume...
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milk intake and energy expenditure of free ranging northern fur seal Callorhinus ursinus pups
Physiological and Biochemical Zoology, 2002Co-Authors: M J Donohue, Daniel P Costa, George A Antonelis, E Goebel, Jason D BakerAbstract:Abstract Milk ingested by mammalian offspring, coupled with offspring’s utilization of this energetic investment, influences survival and growth. A number of studies have examined milk intake in otariids, but few have examined milk intake over the entire lactation period, and none has independently measured energy expenditure concurrent with milk intake. We concurrently examined milk intake, field metabolic rate (FMR), and body composition of 41 pups over the entire lactation interval in 1995 and 1996 on St. Paul Island, Alaska. One hundred two metabolic measurements were obtained with isotope dilution methods. Mean milk intake did not differ annually but increased with age and mass, ranging from \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefau...
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natal site fidelity in northern fur seals Callorhinus ursinus
Animal Behaviour, 1995Co-Authors: Jason D Baker, Charles W Fowler, George A Antonelis, Anne E YorkAbstract:More than 37 000 records of northern fur seals tagged at their natal areas and resighted during a recent mark-recapture study and past commercial harvests, were analysed to study the age and sex variation, and temporal dynamics of natal site fidelity in this highly polygynous, long-lived, migratory species. Data were available on males (2-6 years old) and females (2-20 years old). All ages and sex classes with sufficient sample sizes to allow statistical tests showed a significant tendency to return to the same area of the island where they were born. The proportion of young male and female seals found at their natal area during the breeding season increased significantly with age. Young females showed significantly greater age-specific natal site fidelity than young males (ages 2-6 years) and apparently exhibited their maximum site fidelity at a younger age than males. The increasing expression of natal site fidelity with age appears to be related to sexual maturation and reproductive activity, the latter beginning later in males than in females. Within a season, natal site fidelity of juvenile males increased with time since arrival on St Paul Island. This change in site fidelity implies that they may be less particular in selecting a landing site when they first arrive, then begin to orient more specifically towards their natal area. This behaviour may indicate a transition from a general homing goal while migrating (the island as a whole) to a more specific goal (the natal area) upon arrival.
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the influence of climatic seasonality on the life cycle of the pribilof northern fur seal
Marine Mammal Science, 1994Co-Authors: Andrew W. Trites, George A AntonelisAbstract:Weather conditions recorded from 1956 to 1986 on St. Paul Island, Alaska, were probed to establish their influence upon the northern fur seal's life cycle (Callorhinus ursinus). Air temperatures, wind speeds, and relative humidity levels were seasonally decomposed and compared with the timing of pupping and migration. Most pups are born in early July when air temperatures and relative humidity approach their highest annual levels and wind speeds are at their lowest. Weather conditions favor growth and survival of pups from July to September but are unfavorable in June. A rapid deterioration in weather through October and November corresponds with the fall migration of pups and lactating females. The data suggest the pivotal event in the fur seal's life cycle is the timing of birth and survival of nursing pups. As such, the ultimate determinant of the precisely timed fur seal life cycle appears to be climatic seasonality during the breeding season.
Charles W Fowler - One of the best experts on this subject based on the ideXlab platform.
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natal site fidelity in northern fur seals Callorhinus ursinus
Animal Behaviour, 1995Co-Authors: Jason D Baker, Charles W Fowler, George A Antonelis, Anne E YorkAbstract:More than 37 000 records of northern fur seals tagged at their natal areas and resighted during a recent mark-recapture study and past commercial harvests, were analysed to study the age and sex variation, and temporal dynamics of natal site fidelity in this highly polygynous, long-lived, migratory species. Data were available on males (2-6 years old) and females (2-20 years old). All ages and sex classes with sufficient sample sizes to allow statistical tests showed a significant tendency to return to the same area of the island where they were born. The proportion of young male and female seals found at their natal area during the breeding season increased significantly with age. Young females showed significantly greater age-specific natal site fidelity than young males (ages 2-6 years) and apparently exhibited their maximum site fidelity at a younger age than males. The increasing expression of natal site fidelity with age appears to be related to sexual maturation and reproductive activity, the latter beginning later in males than in females. Within a season, natal site fidelity of juvenile males increased with time since arrival on St Paul Island. This change in site fidelity implies that they may be less particular in selecting a landing site when they first arrive, then begin to orient more specifically towards their natal area. This behaviour may indicate a transition from a general homing goal while migrating (the island as a whole) to a more specific goal (the natal area) upon arrival.
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BODY WEIGHT and GROWTH OF JUVENILE MALE NORTHERN FUR SEALS, Callorhinus URSINUS
Marine Mammal Science, 1994Co-Authors: Jason D Baker, Charles W Fowler, George A AntonelisAbstract: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.
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pup weight and survival of northern fur seals Callorhinus ursinus
Journal of Zoology, 1992Co-Authors: Jason D Baker, Charles W FowlerAbstract:The relationship between northern fur seal pup weight and post-weaning survival is examined. Males that survived at least two years after weaning had been significantly heavier than the mean for their cohort as pups. Among a small sample of females no significant relationship was found. Cohort survival from weaning to age two was not significantly correlated with mean pup weight. Pup weight may influence post-weaning survival less than other factors such as gender and variability of the environment. To the degree that it determines survival, pup weight may reflect the reproductive success or fitness of parents. Weight differences between tagged and untagged pups explain, in part, differences observed in their survival.
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density dependence in northern fur seals Callorhinus ursinus
Marine Mammal Science, 1990Co-Authors: Charles W FowlerAbstract:This paper summarizes, updates, and interprets information on density-dependent dynamics of populations of the northern fur seal (Callorhinus ursinus). Density-dependent changes observed in these populations have involved various aspects of growth (body length, body weight, tooth weight, and size of other skeletal parts, especially the skull), survival, age at maturation, incidence of disease, and time spent foraging. For the population of northern fur seals on St. Paul Island of the Pribilof Islands, which was observed during a major increase and during two significant declines, density-dependent changes that occurred during the growth of the population were reversed during the declines. The Robben Island population in the western Pacific declined after 1965, and the decline was accompanied by changes similar to those observed during the declines on the Pribilof Islands. Although data are not available for all age and sex classes, it appears that most or all components of the populations exhibit similar changes. The overall implication of these changes is that current populations on Robben Island and the Pribilof Islands are reduced to levels below what could be supported by the resources available in their environments. Density dependence for this species is consistent with that of other large mammals, specifically in that vital rates for fur seals ate related to density in a nonlinear fashion.
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tooth weights of juvenile male northern fur seals Callorhinus ursinus
Marine Mammal Science, 1990Co-Authors: Jason D Baker, Charles W FowlerAbstract: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.