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Russel D. Andrews - One of the best experts on this subject based on the ideXlab platform.
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ontogeny of early diving and foraging behavior of Northern Fur Seal callorhinus ursinus pups from bering island russia
Marine Biology, 2014Co-Authors: Russel D. Andrews, Vladimir N Burkanov, Randall W DavisAbstract:The ontogeny of diving and foraging behavior of Northern Fur Seal pups from a stable population on Bering Island, Russia, was recorded with animal-borne instruments during their first few months at sea, a critical period during their first year at sea. Thirty-five pups were instrumented with satellite-linked time-depth recorders and stomach temperature pills. Diving occurred predominantly at night with deeper and longer dives as the pups matured. Mean dive depths were correlated with lunar illumination, whereas mean dive durations were also correlated with time of day and sex. Foraging success did not differ between sexes, and there was no relationship between meal size (as indicated by feeding event duration and minimum stomach temperature) and lunar illumination fraction or maximum foraging depth. Although most pups were able to successfully forage within 3 days of starting their migration, the number of feeding events recorded each day remained low (mean 1.6 events day−1). There was no indication of an appreciable increase in meal size after the first 2 weeks of the migration despite an increase in dive frequency and depth. The results are consistent with observations that pups do not gain mass during their first year and emphasize the risk of starvation from infrequent foraging in cold water.
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influence of environment morphology and instrument size on lactating Northern Fur Seal callorhinus ursinus foraging behavior on the lovushki islands russia
Marine Ecology Progress Series, 2012Co-Authors: John P Skinner, Vladimir N Burkanov, Russel D. AndrewsAbstract:Food limitation may be one of the causes of declines in Northern Fur Seal populations on the Pribilof Islands. This hypothesis could be tested by comparing foraging behavior from decreasing Pribilof Fur Seal populations and an increasing population, such as on the Lovushki Islands, Russia, but factors other than prey availability that differ between sites may also influence behavior. Therefore, we evaluated such factors, including lunar cycle, weather, Seal body size, and size of recording instruments, by studying 41 lactating Northern Fur Seals on Lovushki Island over 4 summer breeding seasons using instrument packages of various sizes. With greater moon- light, Seals increased foraging trip duration, dive depth, dive duration, and time spent on the bot- tom of dives but decreased descent rate and diving bout duration. Larger females made shorter shore visits, spent a greater proportion of time at sea diving, and had longer dive bouts than smaller females. Tags with larger frontal surface areas and higher drag caused Seals to dive longer and to descend and ascend faster during dives but did not affect foraging trip durations or mass change rates. Seals, therefore, appeared capable of compensating for instrument effects on the scale of indi vidual dives. Although lactating Seals from Lovushki Island appeared to spend less foraging effort than Seals from the Pribilofs, future studies should control for methodological fac- tors and local environmental conditions before concluding whether food limitation could explain differences in population trajectories.
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differentiating between steller sea lion eumetopias jubatus and Northern Fur Seal callorhinus ursinus scats through analysis of faecal dna
Molecular Ecology Resources, 2011Co-Authors: Russel D. Andrews, Jason N Waite, Mary Bozza, Lisette P WaitsAbstract:: We describe a method to determine the species of pinniped from faeces collected from sympatric Steller sea lion (Eumetopias jubatus) and Northern Fur Seal (Callorhinus ursinus) rookeries using newly developed species-specific primers that amplify a 667-669-base pair segment from the mitochondrial DNA (mtDNA) cytochrome B (cytB) gene region. The primers yielded the correct species in 100% of tissue samples from 10 known animals and 100% of faecal samples from 13 known animals. Species could be identified unequivocally for 87.7% of faecal samples from 122 unknown individuals. The ability to differentiate between scats of sympatrically breeding Steller sea lions and Northern Fur Seals will contribute to the range-wide knowledge of the foraging strategies of both species as well as allow researchers to examine the niche partitioning and potential resource competition between the two predators.
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differentiating between steller sea lion eumetopias jubatus and Northern Fur Seal callorhinus ursinus scats through analysis of faecal dna
Molecular Ecology Resources, 2011Co-Authors: Russel D. Andrews, Jason N Waite, Mary Bozza, Lisette P WaitsAbstract:: We describe a method to determine the species of pinniped from faeces collected from sympatric Steller sea lion (Eumetopias jubatus) and Northern Fur Seal (Callorhinus ursinus) rookeries using newly developed species-specific primers that amplify a 667-669-base pair segment from the mitochondrial DNA (mtDNA) cytochrome B (cytB) gene region. The primers yielded the correct species in 100% of tissue samples from 10 known animals and 100% of faecal samples from 13 known animals. Species could be identified unequivocally for 87.7% of faecal samples from 122 unknown individuals. The ability to differentiate between scats of sympatrically breeding Steller sea lions and Northern Fur Seals will contribute to the range-wide knowledge of the foraging strategies of both species as well as allow researchers to examine the niche partitioning and potential resource competition between the two predators.
Terry R Spraker - One of the best experts on this subject based on the ideXlab platform.
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Review of metazoan parasites of the Northern Fur Seal (Callorhinus ursinus) and the analysis of the gastrointestinal helminth community of the population on St. Paul Island, Alaska
Parasitology Research, 2021Co-Authors: Tetiana A. Kuzmina, Terry R Spraker, Yuriy Kuzmin, Igor Dzeverin, Olga I. Lisitsyna, Eleonora M. Korol, Roman KuchtaAbstract:The Northern Fur Seal (NFS), Callorhinus ursinus (Mammalia: Otariidae), is a marine mammal species included into the IUCN Red List as the vulnerable species which population is dramatically declining. A significant amount of parasitological data collected previously and our recent data allowed us to clarify the list of NFS metazoan parasites and to perform a comprehensive analysis of the gastrointestinal helminth community. Gastrointestinal tracts from 756 NFSs (3- to 4-year-old males) were collected during the annual Aleut subsistence harvests in July–August of 2011–2014 from five separate rookeries on St. Paul Island, Alaska. Totally, 27,625 specimens of helminths and approximately 1000 nasal mites were collected and identified. Detailed analysis of the previously published and newly obtained data revealed 32 species of metazoan parasites, including trematodes (6 species), cestodes (4), nematodes (9), acanthocephalans (9) and arthropods (4). The gastrointestinal helminth community of newly studied NFSs comprised 19 species including trematodes (4), cestodes (3), nematodes (5) and acanthocephalans (7). Temporal changes in the helminth community structure were small but statistically significant. Gastrointestinal helminth infracommunities comprised from 1 to 10 species (average of 4). Small but significant correlation was found between the abundances of acanthocephalans ( Corynosoma similis and C. strumosum ), nematodes ( Contracaecum osculatum , Pseudoterranova spp.) and cestode Diphyllobothrium tetrapterum .
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a study of uncinariasis in Northern Fur Seal pups callorhinus ursinus on the rookeries of bering island 2011 2012
Russian Journal of Marine Biology, 2019Co-Authors: Sergey V Fomin, L I Konovalova, O A Belonovich, Robert L. Delong, Terry R SprakerAbstract:Carcasses of Northern Fur Seal pups, Callorhinus ursinus, collected from the rookeries of Bering Island (n = 133), were examined for hookworms Uncinaria spp. The parasite was found in 90% of the pups from the Severo-Zapadnoe rookery and in 45% of the pups from the Severnoe rookery. This difference in prevalence of nematode infection between the rookeries is associated with the type of substrate, as well as with the pattern of distribution of the Seal reproductive groups on each of the rookeries.
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A Study of Uncinariasis in Northern Fur Seal Pups, Callorhinus ursinus , on the Rookeries of Bering Island, 2011–2012
Russian Journal of Marine Biology, 2019Co-Authors: Sergey V Fomin, L I Konovalova, O A Belonovich, R. L. Delong, Terry R SprakerAbstract:Carcasses of Northern Fur Seal pups, Callorhinus ursinus, collected from the rookeries of Bering Island (n = 133), were examined for hookworms Uncinaria spp. The parasite was found in 90% of the pups from the Severo-Zapadnoe rookery and in 45% of the pups from the Severnoe rookery. This difference in prevalence of nematode infection between the rookeries is associated with the type of substrate, as well as with the pattern of distribution of the Seal reproductive groups on each of the rookeries.
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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, Sophie Dennison, William Van Bonn, 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, Carol Hearne, Tracey Goldstein, 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.
Robert L. Delong - One of the best experts on this subject based on the ideXlab platform.
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a study of uncinariasis in Northern Fur Seal pups callorhinus ursinus on the rookeries of bering island 2011 2012
Russian Journal of Marine Biology, 2019Co-Authors: Sergey V Fomin, L I Konovalova, O A Belonovich, Robert L. Delong, Terry R SprakerAbstract:Carcasses of Northern Fur Seal pups, Callorhinus ursinus, collected from the rookeries of Bering Island (n = 133), were examined for hookworms Uncinaria spp. The parasite was found in 90% of the pups from the Severo-Zapadnoe rookery and in 45% of the pups from the Severnoe rookery. This difference in prevalence of nematode infection between the rookeries is associated with the type of substrate, as well as with the pattern of distribution of the Seal reproductive groups on each of the rookeries.
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investigations of peritoneal and intestinal infections of adult hookworms uncinaria spp in Northern Fur Seal callorhinus ursinus and california sea lion zalophus californianus pups on san miguel island california 2003
Parasitology Research, 2011Co-Authors: Robert L. Delong, Steven A Nadler, Jeffrey L Laake, B L Delong, Cecile PaganAbstract:The peritoneal cavity (PNC) and intestine of Northern Fur Seal (Callorhinus ursinus) pups and California sea lion (Zalophus californianus) pups that died in late July and early August, 2003, on San Miguel Island, California, were examined for hookworms. Prevalence and morphometric studies were done with the hookworms in addition to molecular characterization. Based on this and previous molecular studies, hookworms from Fur Seals are designated as Uncinaria lucasi and the species from sea lions as Uncinaria species A. Adult hookworms were found in the PNC of 35 of 57 (61.4%) Fur Seal pups and of 13 of 104 (12.5%) sea lion pups. The number of hookworms located in the PNC ranged from 1 to 33 (median = 3) for the infected Fur Seal pups and 1 to 16 (median = 2) for the infected sea lion pups. In addition to the PNC, intestines of 43 Fur Seal and 32 sea lion pups were examined. All of these pups were positive for adult hookworms. The worms were counted from all but one of the sea lion pups. Numbers of these parasites in the intestine varied from 3 to 2,344 (median = 931) for the Fur Seal pups and 39 to 2,766 (median = 643) for the sea lion pups. Sea lion pups with peritoneal infections had higher intensity infections in the intestines than did pups without peritoneal infections, lending some support for the hypothesis that peritoneal infections result from high-intensity infections of adult worms. There was no difference in intestinal infection intensities between Fur Seal pups with and without peritoneal infections. Female adult hookworms in the intestines of both host species were significantly larger than males, and sea lion hookworms were larger than those in Fur Seals. Worms in the intestine also were larger than worms found in the PNC. Gene sequencing and (RFLP) analysis of (PCR) amplified (ITS) ribosomal DNA were used to diagnose the species of 172 hookworms recovered from the PNC and intestine of 18 C. ursinus and seven Z. californianus hosts. These molecular data revealed that U. lucasi (hookworm of C. ursinus) and Uncinaria species A (of Z. californianus) infrequently mature in the intestine of the opposite host species in California rookeries. However, there is no support from molecular data for the hypothesis that cross-infection with “the wrong” Uncinaria species is a contributing factor in these cases of host peritonitis. The major significance of this research is the unusual finding of adult hookworms in the PNC of so many dead pups. No obvious explanation for this occurrence could be determined. Further research, like in the present study, should help understand and monitor the apparent ever changing role of hookworm disease in the health of Northern Fur Seal and California sea lion pups on SMI.
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current prevalence of adult uncinaria spp in Northern Fur Seal callorhinus ursinus and california sea lion zalophus californianus pups on san miguel island california with notes on the biology of these hookworms
Veterinary Parasitology, 2001Co-Authors: Sharon R. Melin, Robert L. Delong, Frances M. D. GullandAbstract:Abstract A prevalence survey for hookworms (Uncinaria spp.) was done in Northern Fur Seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups on San Miguel Island, CA, in 2000. Intestines of dead pups were examined for adult hookworms in July. These parasites were found in 95% of 20 Fur Seal pups and 100% of 31 sea lion pups. The number of hookworms varied from 4 to 2142 ( x =760 ) in Fur Seal pups and from 20 to 2634 ( x =612 ) in sea lion pups. A direct relationship was evident between body condition and number of hookworms in the pups; that is, pups in poor condition had fewer hookworms than those in good condition. There was a decline in the number of hookworms in sea lion pups in 2000 compared to collections in 1996. Eggs of Uncinaria spp. were found in rectal feces (collected in late September and early October) of none of 35 (0%) live Fur Seal pups and 41 of 48 (85%) live sea lion pups. Packed cell volume values, determined for most of the same live pups, were essentially normal for C. ursinus but were much lower than normal for most Z. californianus. Hookworm larvae were not found in blubber of Fur Seal and sea lion pups or in rookery sand in July. Rookery sand, positive for live hookworm larvae when put in a refrigerator, was negative at removal 2.5 years later. The average number of eggs in utero of female hookworms was 285 for three specimens from a Fur Seal pup and 281 from three specimens from a sea lion pup. One hookworm larva was recovered from milk stripped from the teats of a stranded Z. californianus female at The Marine Mammal Center, Sausalito, CA.
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current prevalence of adult uncinaria spp in Northern Fur Seal callorhinus ursinus and california sea lion zalophus californianus pups on san miguel island california with notes on the biology of these hookworms
Veterinary Parasitology, 2001Co-Authors: E T Lyons, Robert L. Delong, Sharon R. Melin, Frances M. D. Gulland, Anthony J Orr, S C TolliverAbstract:A prevalence survey for hookworms (Uncinaria spp.) was done in Northern Fur Seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups on San Miguel Island, CA, in 2000. Intestines of dead pups were examined for adult hookworms in July. These parasites were found in 95% of 20 Fur Seal pups and 100% of 31 sea lion pups. The number of hookworms varied from 4 to 2142 (mean = 760) in Fur Seal pups and from 20 to 2634 (mean = 612) in sea lion pups. A direct relationship was evident between body condition and number of hookworms in the pups; that is, pups in poor condition had fewer hookworms than those in good condition. There was a decline in the number of hookworms in sea lion pups in 2000 compared to collections in 1996. Eggs of Uncinaria spp. were found in rectal feces (collected in late September and early October) of none of 35 (0%) live Fur Seal pups and 41 of 48 (85%) live sea lion pups. Packed cell volume values, determined for most of the same live pups, were essentially normal for C. ursinus but were much lower than normal for most Z. californianus. Hookworm larvae were not found in blubber of Fur Seal and sea lion pups or in rookery sand in July. Rookery sand, positive for live hookworm larvae when put in a refrigerator, was negative at removal 2.5 years later. The average number of eggs in utero of female hookworms was 285 for three specimens from a Fur Seal pup and 281 from three specimens from a sea lion pup. One hookworm larva was recovered from milk stripped from the teats of a stranded Z. californianus female at The Marine Mammal Center, Sausalito, CA.
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Comparative Biology of Uncinaria Spp. in the California Sea Lion (Zalophus californianus) and the Northern Fur Seal (Callorhinus ursinus) in California
Journal of Parasitology, 2000Co-Authors: Robert L. Delong, Sharon R. Melin, Terry R SprakerAbstract:Studies on several aspects of the life cycle of hookworms (Uncinaria spp.) in the California sea lion (Zalophus californianus) and Northern Fur Seal (Callorhinus ursinus) were conducted on material collected on San Miguel Island (SMI), California and at The Marine Mammal Center, Sausalito, California in 1997, 1998, and 1999. Examination of Z. californianus intestines for adult hookworms and feces for eggs revealed that longevity of these parasites in pups is about 6–8 mo, and infections are probably not present in older sea lions. Parasitic third-stage larvae (L3) were recovered from the ventral abdominal tissue of Z. californianus, suggesting transmammary transmission. Callorhinus ursinus pups had no hookworm eggs in their feces or adult worms (except for 1 probable contaminant) in their intestines in the fall and early winter, revealing that adult Uncinaria spp. are spontaneously lost at
Jason N Waite - One of the best experts on this subject based on the ideXlab platform.
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differentiating between steller sea lion eumetopias jubatus and Northern Fur Seal callorhinus ursinus scats through analysis of faecal dna
Molecular Ecology Resources, 2011Co-Authors: Russel D. Andrews, Jason N Waite, Mary Bozza, Lisette P WaitsAbstract:: We describe a method to determine the species of pinniped from faeces collected from sympatric Steller sea lion (Eumetopias jubatus) and Northern Fur Seal (Callorhinus ursinus) rookeries using newly developed species-specific primers that amplify a 667-669-base pair segment from the mitochondrial DNA (mtDNA) cytochrome B (cytB) gene region. The primers yielded the correct species in 100% of tissue samples from 10 known animals and 100% of faecal samples from 13 known animals. Species could be identified unequivocally for 87.7% of faecal samples from 122 unknown individuals. The ability to differentiate between scats of sympatrically breeding Steller sea lions and Northern Fur Seals will contribute to the range-wide knowledge of the foraging strategies of both species as well as allow researchers to examine the niche partitioning and potential resource competition between the two predators.
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differentiating between steller sea lion eumetopias jubatus and Northern Fur Seal callorhinus ursinus scats through analysis of faecal dna
Molecular Ecology Resources, 2011Co-Authors: Russel D. Andrews, Jason N Waite, Mary Bozza, Lisette P WaitsAbstract:: We describe a method to determine the species of pinniped from faeces collected from sympatric Steller sea lion (Eumetopias jubatus) and Northern Fur Seal (Callorhinus ursinus) rookeries using newly developed species-specific primers that amplify a 667-669-base pair segment from the mitochondrial DNA (mtDNA) cytochrome B (cytB) gene region. The primers yielded the correct species in 100% of tissue samples from 10 known animals and 100% of faecal samples from 13 known animals. Species could be identified unequivocally for 87.7% of faecal samples from 122 unknown individuals. The ability to differentiate between scats of sympatrically breeding Steller sea lions and Northern Fur Seals will contribute to the range-wide knowledge of the foraging strategies of both species as well as allow researchers to examine the niche partitioning and potential resource competition between the two predators.
Sharon R. Melin - One of the best experts on this subject based on the ideXlab platform.
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Chaired session on Climate Change: Climate influences on dispersal and survival of Northern Fur Seal pups
2011Co-Authors: Mary-anne Lea, Sharon R. Melin, Jeremy T. Sterling, R. R. Ream, N Bond, Thomas S GelattAbstract:Northern Fur Seal pups, Callorhinus ursinus , from declining populations in the Bering Sea contend with extreme and highly variable oceanic conditions during their first winter migrations. Understanding how naive animals from increasing and decreasing populations respond to changeable environmental cues is fundamental to disentangling possible mechanisms driving observed, large-scale declines. We tracked 166 newly-weaned pups from four North American populations, both increasing and decreasing, to determine the influence of wind conditions, sea surface height and temperature and proximity to productive frontal features on the foraging state of individual pups. Pups conducted far-ranging migrations across the North Pacific Ocean, triggered by the onset of autumnal storms. At-sea conditions differed markedly between the two years as did pup movements. Alaskan pups travelled faster when ‘assisted’ by tailwinds and spent more time in Northern latitudes in less stormy years. The migration patterns of pups were more random than those published for adults also indicating that young animals undergo a period of learning at sea. We provide examples and speculate on how storms may impact survival of naive pups, particularly in years when pup weaning mass is low. We conclude that increasing intensity and frequency of storm events in the North Pacific Ocean could have repercussions on pup behaviour and population demographics of Northern Fur Seals across their range.
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diving ontogeny and lunar responses in a highly migratory mammal the Northern Fur Seal callorhinus ursinus
Marine Ecology Progress Series, 2010Co-Authors: Devin S Johnson, Sharon R. Melin, Rolf R Ream, Tom GelattAbstract:Diving ontogeny studies enable the examination of both the evolution of diving strate- gies and the physiological constraints and environmental factors determining foraging behaviour. Northern Fur Seal (NFS) Callorhinus ursinus pups that undertake far-ranging migrations in their first year are an ideal species for examining such factors. The diving behaviour of 64 NFS pups from 4 North American breeding sites was studied using satellite-dive recorders deployed on pups prior to weaning. Summarised diving activity (6 h histograms of dive depth and duration) was recorded dur- ing the pups' first 8 mo at sea and transmitted via satellite. During the first month at sea, pups adopted the nocturnal diving patterns characteristic of adults, with average maximum nightly and crepuscular dive depths and durations exceeding daytime values by a factor of from 4 to 4.5. Diving capacity in terms of maximum depths (112 m) and durations (285 s) attained also increased linearly with age until ~8 to 10 mo of age. Overlaid on diving capability development was the significant influence of environmental cues, such as lunar phase, on migratory diving behaviour. During full moons, pups dived deeper and for longer periods than during other lunar phases, as pups likely mim- icked the behaviour of their vertically migrating prey. These findings indicate that prey accessibility, particularly for younger pups with reduced diving capacity, may prove more challenging during higher lunar illumination periods.
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current prevalence of adult uncinaria spp in Northern Fur Seal callorhinus ursinus and california sea lion zalophus californianus pups on san miguel island california with notes on the biology of these hookworms
Veterinary Parasitology, 2001Co-Authors: Sharon R. Melin, Robert L. Delong, Frances M. D. GullandAbstract:Abstract A prevalence survey for hookworms (Uncinaria spp.) was done in Northern Fur Seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups on San Miguel Island, CA, in 2000. Intestines of dead pups were examined for adult hookworms in July. These parasites were found in 95% of 20 Fur Seal pups and 100% of 31 sea lion pups. The number of hookworms varied from 4 to 2142 ( x =760 ) in Fur Seal pups and from 20 to 2634 ( x =612 ) in sea lion pups. A direct relationship was evident between body condition and number of hookworms in the pups; that is, pups in poor condition had fewer hookworms than those in good condition. There was a decline in the number of hookworms in sea lion pups in 2000 compared to collections in 1996. Eggs of Uncinaria spp. were found in rectal feces (collected in late September and early October) of none of 35 (0%) live Fur Seal pups and 41 of 48 (85%) live sea lion pups. Packed cell volume values, determined for most of the same live pups, were essentially normal for C. ursinus but were much lower than normal for most Z. californianus. Hookworm larvae were not found in blubber of Fur Seal and sea lion pups or in rookery sand in July. Rookery sand, positive for live hookworm larvae when put in a refrigerator, was negative at removal 2.5 years later. The average number of eggs in utero of female hookworms was 285 for three specimens from a Fur Seal pup and 281 from three specimens from a sea lion pup. One hookworm larva was recovered from milk stripped from the teats of a stranded Z. californianus female at The Marine Mammal Center, Sausalito, CA.
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current prevalence of adult uncinaria spp in Northern Fur Seal callorhinus ursinus and california sea lion zalophus californianus pups on san miguel island california with notes on the biology of these hookworms
Veterinary Parasitology, 2001Co-Authors: E T Lyons, Robert L. Delong, Sharon R. Melin, Frances M. D. Gulland, Anthony J Orr, S C TolliverAbstract:A prevalence survey for hookworms (Uncinaria spp.) was done in Northern Fur Seal (Callorhinus ursinus) and California sea lion (Zalophus californianus) pups on San Miguel Island, CA, in 2000. Intestines of dead pups were examined for adult hookworms in July. These parasites were found in 95% of 20 Fur Seal pups and 100% of 31 sea lion pups. The number of hookworms varied from 4 to 2142 (mean = 760) in Fur Seal pups and from 20 to 2634 (mean = 612) in sea lion pups. A direct relationship was evident between body condition and number of hookworms in the pups; that is, pups in poor condition had fewer hookworms than those in good condition. There was a decline in the number of hookworms in sea lion pups in 2000 compared to collections in 1996. Eggs of Uncinaria spp. were found in rectal feces (collected in late September and early October) of none of 35 (0%) live Fur Seal pups and 41 of 48 (85%) live sea lion pups. Packed cell volume values, determined for most of the same live pups, were essentially normal for C. ursinus but were much lower than normal for most Z. californianus. Hookworm larvae were not found in blubber of Fur Seal and sea lion pups or in rookery sand in July. Rookery sand, positive for live hookworm larvae when put in a refrigerator, was negative at removal 2.5 years later. The average number of eggs in utero of female hookworms was 285 for three specimens from a Fur Seal pup and 281 from three specimens from a sea lion pup. One hookworm larva was recovered from milk stripped from the teats of a stranded Z. californianus female at The Marine Mammal Center, Sausalito, CA.
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Comparative Biology of Uncinaria Spp. in the California Sea Lion (Zalophus californianus) and the Northern Fur Seal (Callorhinus ursinus) in California
Journal of Parasitology, 2000Co-Authors: Robert L. Delong, Sharon R. Melin, Terry R SprakerAbstract:Studies on several aspects of the life cycle of hookworms (Uncinaria spp.) in the California sea lion (Zalophus californianus) and Northern Fur Seal (Callorhinus ursinus) were conducted on material collected on San Miguel Island (SMI), California and at The Marine Mammal Center, Sausalito, California in 1997, 1998, and 1999. Examination of Z. californianus intestines for adult hookworms and feces for eggs revealed that longevity of these parasites in pups is about 6–8 mo, and infections are probably not present in older sea lions. Parasitic third-stage larvae (L3) were recovered from the ventral abdominal tissue of Z. californianus, suggesting transmammary transmission. Callorhinus ursinus pups had no hookworm eggs in their feces or adult worms (except for 1 probable contaminant) in their intestines in the fall and early winter, revealing that adult Uncinaria spp. are spontaneously lost at
