Publications

standardized protocols for plasma clearance of iohexol are not appropriate for determination of glomerular filtration rates in anesthetized california sea lions (zalophus californianus).	abstract: plasma clearance of iohexol was evaluated in eight anesthetized california sea lions (zalophus californianus), without evidence of renal dysfunction, to determine if the one-compartment model and the sample protocol used in dogs and cats could be applied to this species. nonlinearity between samples in 75% (6/8) of sea lions voided those results. an additional two anesthetized sea lions were sampled at 5, 30, 45, 60, 120, 180, 240, and 360 min post iohexol injection and semi-logarithmi ...	2010	20722269
the cost of male aggression and polygyny in california sea lions (zalophus californianus).	in polygynous mating systems, males often increase their fecundity via aggressive defense of mates and/or resources necessary for successful mating. here we show that both male and female reproductive behavior during the breeding season (june-august) affect female fecundity, a vital rate that is an important determinant of population growth rate and viability. by using 4 years of data on behavior and demography of california sea lions (zalophus californianus), we found that male behavior and spa ...	2010	20808931
characterization of progressive keratitis in otariids.	to characterize a form of progressive keratitis that occurs commonly in otariids.	2010	20840090
anatomy of the california sea lion globe.	this study analyzed the morphology of the california sea lion globe to determine what features may contribute to their characteristic visual abilities.	2010	20840092
hydrodynamic trail following in a california sea lion (zalophus californianus).	the mystacial vibrissae of pinnipeds constitute a sensory system for active touch and detection of hydrodynamic events. harbour seals (phoca vitulina) and california sea lions (zalophus californianus) can both detect hydrodynamic stimuli caused by a small sphere vibrating in the water (hydrodynamic dipole stimuli). hydrodynamic trail following has only been shown in harbour seals. hydrodynamical and biomechanical studies of single vibrissae of the two species showed that the specialized undulate ...	2011	20959994
phylogenetic analysis of marine mammal herpesviruses.	five novel dna-dependent dna polymerase (dpol) herpesviral sequences were generated using nested consensus polymerase chain reaction (pcr) in clinical samples from a harbor seal (phoca vitulina), bottlenose dolphin (tursiops truncatus), orca (orcinus orca), california sea lion (zalophus californianus), and a phocid herpesvirus 2 (phhv-2) isolate from a harbor seal (used as positive control). these novel sequences and other representative herpesvirus sequences were included in bayesian and maximu ...	2010	21055885
first evidence for adoption in california sea lions.	demographic parameters such as birth and death rates determine the persistence of populations. understanding the mechanisms that influence these rates is essential to developing effective management strategies. alloparental behavior, or the care of non-filial young, has been documented in many species and has been shown to influence offspring survival. however, the role of alloparental behavior in maintaining population viability has not been previously studied. here, we provide the first eviden ...	2010	21079727
acoustic characteristics of ultrasonic coded transmitters for fishery applications: could marine mammals hear them?	ultrasonic coded transmitters (ucts) producing frequencies of 69-83 khz are used increasingly to track fish and invertebrates in coastal and estuarine waters. to address concerns that they might be audible to marine mammals, acoustic properties of ucts were measured off mission beach, san diego, and at the u.s. navy transdec facility. a regression model fitted to vemco uct data yielded an estimated source level of 147 db re 1 μpa spl @ 1 m and spreading constant of 14.0. based on transdec measur ...	2010	21110617
novel hemotrophic mycoplasma identified in naturally infected california sea lions (zalophus californianus).	the hemoplasmas are the trivial name for a group of erythrocyte-parasitizing, non-cultivable in vitro bacteria of the genus mycoplasma that have been described in several mammalian hosts worldwide. this study is the first report of hemoplasmas in marine mammals. edta anticoagulated whole blood samples from 137 california sea lions (zalophus californianus) and 20 northern elephant seals (mirounga angustirostris) admitted to the marine mammal center (sausalito, ca; www.marinemammalcenter.org) or l ...	2010	21111543
magnetic resonance imaging quality and volumes of brain structures from live and postmortem imaging of california sea lions with clinical signs of domoic acid toxicosis.	our goal in this study was to compare magnetic resonance images and volumes of brain structures obtained alive versus postmortem of california sea lions zalophus californianus exhibiting clinical signs of domoic acid (da) toxicosis and those exhibiting normal behavior. proton density-(pd) and t2-weighted images of postmortem-intact brains, up to 48 h after death, provided similar quality to images acquired from live sea lions. volumes of gray matter (gm) and white matter (wm) of the cerebral hem ...	2010	21133324
segniliparus rugosus-associated bronchiolitis in california sea lion.		2011	21291617
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).	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 a ...	2011	21347520
rapid behavioural diagnosis of domoic acid toxicosis in california sea lions.	domoic acid is a neurotoxic metabolite of widely occurring algal blooms that has caused multiple marine animal stranding events. exposure to high doses of domoic acid, a glutamate agonist, may lead to persistent medial temporal seizures and damage to the hippocampus. california sea lions (zalophus californianus) are among the most visible and frequent mammalian victims of domoic acid poisoning, but rapid, reliable diagnosis in a clinical setting has proved difficult owing to the fast clearance o ...	2011	21389016
aerial audiograms of several california sea lions (zalophus californianus) and steller sea lions (eumetopias jubatus) measured using single and multiple simultaneous auditory steady-state response methods.	measurements of the electrophysiological auditory steady-state response (assr) have proven to be efficient for evaluating hearing sensitivity in odontocete cetaceans. in an effort to expand these methods to pinnipeds, assrs elicited by single and multiple simultaneous tones were used to measure aerial hearing thresholds in several california sea lions (zalophus californianus) and steller sea lions (eumetopias jubatus). there were no significant differences between thresholds measured using the s ...	2011	21389199
metagenomic identification of a novel anellovirus in pacific harbor seal (phoca vitulina richardsii) lung samples and its detection in samples from multiple years.	to investigate viral pathogens potentially involved in a mortality event of 21 pacific harbor seals (phoca vitulina richardsii) in california in 2000, viral metagenomics was performed directly on lung samples from five individuals. metagenomics revealed a novel seal anellovirus (sealav), which clusters phylogenetically with anelloviruses from california sea lions and domestic cats. using specific pcr, sealav was identified in lung tissue from two of five animals involved in the 2000 mortality ev ...	2011	21402596
human disturbance influences reproductive success and growth rate in california sea lions (zalophus californianus).	the environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. to do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. we in ...	2011	21436887
characterization of california sea lion polyomavirus 1: expansion of the known host range of the polyomaviridae to carnivora.	the genome of a novel polyomavirus first identified in a proliferative tongue lesion of a california sea lion (zalophus californianus) is reported. this is only the third described polyomavirus of laurasiatherian mammals, is the first of the three associated with a lesion, and is the first known polyomavirus of a host in the order carnivora. predicted large t, small t, vp1, vp2, and vp3 genes were identified based on homology to proteins of known polyomaviruses, and a putative agnoprotein was id ...	2011	21453794
california sea lion (zalophus californianus) aerial hearing sensitivity measured using auditory steady-state response and psychophysical methods.	although electrophysiological methods of measuring the hearing sensitivity of pinnipeds are not yet as refined as those for dolphins and porpoises, they appear to be a promising supplement to traditional psychophysical procedures. in order to further standardize electrophysiological methods with pinnipeds, a within-subject comparison of psychophysical and auditory steady-state response (assr) measures of aerial hearing sensitivity was conducted with a 1.5-yr-old california sea lion. the psychoph ...	2011	21476685
discovery of three novel coccidian parasites infecting california sea lions (zalophus californianus) with evidence of sexual replication and interspecies pathogenicity.	abstract enteric protozoal infection was identified in 5 stranded california sea lions (zalophus californianus). microscopically, the apical cytoplasm of distal jejunal enterocytes contained multiple stages of coccidian parasites, including schizonts with merozoites and spherical gametocytes, morphologically similar to coccidian parasites. by histopathology, organisms appeared to be confined to the intestine and accompanied by only mild enteritis. using electron microscopy, both sexual (microgam ...	2011	21495828
antemortem diagnosis of a ventricular septal defect in a california sea lion zalophus californianus.	a yearling california sea lion zalophus californianus stranded in poor body condition, and on physical examination a heart murmur was audible bilaterally. the sea lion was diagnosed with a left-to-right shunting membranous ventricular septal defect (vsd) using b-mode, color-flow doppler and continuous-wave doppler echocardiography. a left-to-right intracardiac shunting lesion was confirmed during cardiac angiographic computed tomography. the vsd defect was verified during the necropsy examinatio ...	2011	21553571
isolation of a novel adenovirus from california sea lions zalophus californianus.	viral hepatitis associated with adenoviral infection has been reported in california sea lions zalophus californianus admitted to rehabilitation centers along the california coast since the 1970s. canine adenovirus 1 (cadv-1) causes viral hepatitis in dogs and infects a number of wildlife species. attempts to isolate the virus from previous sea lion hepatitis cases were unsuccessful, but as the hepatitis had morphologic features resembling canine infectious hepatitis, and since the virus has a w ...	2011	21790072
the fecal viral flora of california sea lions.	california sea lions are one of the major marine mammal species along the pacific coast of north america. sea lions are susceptible to wide variety of viruses, some of which can be transmitted to or from terrestrial mammals. using an unbiased viral metagenomic approach we surveyed the fecal virome in california sea lions of different ages and health status. an average of 1.6 and 2.5 distinct mammalian viral species was shed by pups and juvenile sea lions respectively. previously undescribed, mam ...	2011	21795334
latitudinal range influences the seasonal variation in the foraging behavior of marine top predators.	non-migratory resident species should be capable of modifying their foraging behavior to accommodate changes in prey abundance and availability associated with a changing environment. populations that are better adapted to change will have higher foraging success and greater potential for survival in the face of climate change. we studied two species of resident central place foragers from temperate and equatorial regions with differing population trends and prey availability associated to seaso ...	2011	21853081
domoic acid induced status epilepticus promotes aggressive behavior in rats.	domoic acid (da), a naturally occurring environmental toxin, has been observed to induce status epilepticus in humans, sea lions and pelicans. in a recent sprague dawley rat model, domoic acid dosing induced a state of status epilepticus which, after a symptom-free latent period without further dosing, progressed to recurrent spontaneous seizures, a hallmark of epilepsy. certain individuals in this study also developed unusual behavioral changes, in particular an atypical aggression towards cons ...	2012	21875611
dolphin and sea lion auditory evoked potentials in response to single and multiple swept amplitude tones.	measurement of the auditory steady-state response (assr) is increasingly used to assess marine mammal hearing. these tests normally entail measuring the assr to a sequence of sinusoidally amplitude modulated tones, so that the assr amplitude function can be defined and the auditory threshold estimated. in this study, an alternative method was employed, where the assr was elicited by an amplitude modulated stimulus whose sound pressure level was slowly varied, or "swept," over a range of levels b ...	2011	21877816
serological evidence of toxoplasma gondii infection in captive marine mammals in mexico.	toxoplasma gondii infection in marine mammals is important because they are considered as a sentinel for contamination of seas with t. gondii oocysts, and toxoplasmosis causes mortality in these animals, particularly sea otters. serological evidence of t. gondii infection was determined in 75 captive marine mammals from four facilities in southern and central geographical regions in mexico using the modified agglutination test (mat). antibodies (mat, 1:25 or higher) to t. gondii were found in 55 ...	2011	21944844
flow sensing by pinniped whiskers.	beside their haptic function, vibrissae of harbour seals (phocidae) and california sea lions (otariidae) both represent highly sensitive hydrodynamic receptor systems, although their vibrissal hair shafts differ considerably in structure. to quantify the sensory performance of both hair types, isolated single whiskers were used to measure vortex shedding frequencies produced in the wake of a cylinder immersed in a rotational flow tank. these measurements revealed that both whisker types were abl ...	2011	21969689
Characterization of a novel papillomavirus species (ZcPV1) from two California sea lions (Zalophus californianus).	A seven-year old California sea lion (Zalophus californianus) presented with focally extensive, bilaterally symmetric, proliferative axillary skin lesions and preputial lesions. A second California sea lion in the same population presented with similar proliferative lesions on the underside of the tail. Histopathology revealed epidermal hyperplasia with severe hyperkeratosis, with proliferating keratinocytes forming broad, branching pegs that extended into the dermis. Pan-papillomaviral consensu ...	2011	22005176
evidence of injury caused by gas bubbles in a live marine mammal: barotrauma in a california sea lion zalophus californianus.	a yearling male california sea lion zalophus californianus with hypermetric ataxia and bilateral negative menace reflexes was brought to the marine mammal center, sausalito, california, u.s.a., in late 2009 for medical assessment and treatment. the clinical signs were due to multiple gas bubbles within the cerebellum. these lesions were intraparenchymal, multifocal to coalescing, spherical to ovoid, and varied from 0.5 to 2.4 cm diameter. the gas composed 21.3% of the total cerebellum volume. th ...	2011	22013748
health status, infection and disease in california sea lions (zalophus californianus) studied using a canine microarray platform and machine-learning approaches.	conservation biologists face many challenges in assessing health, immune status and infectious diseases in protected species. these challenges include unpredictable sample populations, diverse genetic and environmental backgrounds of the animals, as well as the practical, legal and ethical issues involved in experimentation. the use of whole genome scale transcriptomics with animal samples obtained in a minimally invasive manner is an approach that shows promise for health assessment. in this st ...	2011	22067742
identification of two novel coccidian species shed by california sea lions (zalophus californianus).	abstract routine fecal examination revealed novel coccidian oocysts in asymptomatic californa sea lions (zalophus californianus) in a rehabilitation facility. coccidian oocysts were observed in fecal samples collected from 15 of 410 california sea lions admitted to the marine mammal center between april 2007 and october 2009. phylogenetic analysis using the full its-1 region, partial small subunit 18s rdna sequence and the apicomplexa rpob region identified 2 distinct sequence clades, referred ...	2011	22091999
Otariodibacter oris gen. nov., sp. nov., a new member of the family Pasteurellaceae isolated from the oral cavity of pinnipeds.	A total of 27 bacterial isolates from California sea lions and a walrus tentatively classified with the family Pasteurellaceae were further characterized by geno- and phenotypic tests. Phylogenetic analysis of partial 16S rRNA and rpoB gene sequences showed that the isolates investigated formed a monophyletic group, tentatively designated Bisgaard taxon 57. According to 16S rRNA gene sequence, the closest related validly named species was Bisgaardia hudsonensis with 95 % similarity and the close ...	2011	22199211
diagnosis and treatment of sarcocystis neurona-induced myositis in a free-ranging california sea lion.	an underweight, lethargic adult female california sea lion (zalophus californianus) became stranded along the california shore and was captured and transported to a rehabilitation hospital for assessment and care.	2012	22256850
the distribution of 4-nonylphenol in marine organisms of north american pacific coast estuaries.	one of the chemical breakdown products of nonylphenol ethoxylates, 4-nonylphenol (4-np), accumulates in organisms and is of concern as an environmental pollutant due to its endocrine disrupting effects. we measured 4-np levels in the seawater, sediment, and twelve organisms within the california estuary, morro bay, and examined biomagnification of 4-np using stable isotope abundances (δ(15)n and δ(13)c) to quantify trophic position. 4-np concentrations in organisms from morro bay included 25000± ...	2012	22257992
toxicokinetics of domoic acid in the fetal rat.	domoic acid (da) is a potent neurotoxin that has both marine wildlife and human health impacts, including developmental effects during prenatal exposure in rodent models. however, little is known regarding da toxicokinetics in the fetal unit during maternal-fetal transfer. tissue distribution and toxicokinetics of da were investigated in pregnant rats and their pups just prior to birth at gestational day 20. pregnant sprague dawley rats were given an intravenous dose of 1.0 mg da/kg and samples ...	2012	22306965
serum profiling by maldi-tof mass spectrometry as a diagnostic tool for domoic acid toxicosis in california sea lions.	there are currently no reliable markers of acute domoic acid toxicosis (dat) for california sea lions. we investigated whether patterns of serum peptides could diagnose acute dat. serum peptides were analyzed by maldi-tof mass spectrometry from 107 sea lions (acute dat n = 34; non-dat n = 73). artificial neural networks (ann) were trained using maldi-tof data. individual peaks and neural networks were qualified using an independent test set (n = 20).	2012	22429742
weak polygyny in california sea lions and the potential for alternative mating tactics.	female aggregation and male territoriality are considered to be hallmarks of polygynous mating systems. the development of genetic parentage assignment has called into question the accuracy of behavioral traits in predicting true mating systems. in this study we use 14 microsatellite markers to explore the mating system of one of the most behaviorally polygynous species, the california sea lion (zalophus californianus). we sampled a total of 158 female-pup pairs and 99 territorial males across t ...	2012	22432039
multicentric neurofibromatosis with rectal prolapse in a california sea lion (zalophus californianus).	an approximately 31-yr-old california sea lion (zalophus californianus) with a history of chronic visual impairment and corneal disease presented with slow onset, progressive neurologic deficits. treatment for rear flipper paresis was not effective and the animal was euthanatized. histopathologic findings included hepatocellular and biliary neoplasia, ocular amyloidosis, adrenal adenoma and pheochromocytoma, and spinal cord changes consistent with multicentric neurofibromatosis. this is the firs ...	2012	22448517
systemic mycosis in a california sea lion (zalophus californianus) with detection of cystofilobasidiales dna.	a 6-yr-old, intact male california sea lion (zalophus californianus) with a systemic mycosis died after 5 wk of antifungal drug therapy. antemortem clinical findings included hind flipper swelling, ring-lesions on skin of the flippers, and dermal nodules that increased in size and number spreading from the hind flippers and ventral abdomen to the foreflippers and muzzle. lesions were accompanied by severe lymphadenopathy and development of systemic clinical signs despite therapy using itraconazo ...	2012	22448522
underwater psychophysical audiogram of a young male california sea lion (zalophus californianus).	auditory evoked potential (aep) data are commonly obtained in air while sea lions are under gas anesthesia; a procedure that precludes the measurement of underwater hearing sensitivity. this is a substantial limitation considering the importance of underwater hearing data in designing criteria aimed at mitigating the effects of anthropogenic noise exposure. to determine if some aspects of underwater hearing sensitivity can be predicted using rapid aerial aep methods, this study measured underwat ...	2012	22559389
seasonal variation in blood and muscle oxygen stores attributed to diving behavior, environmental temperature and pregnancy in a marine predator, the california sea lion.	survival depends on an animal's ability to find and acquire prey. in diving vertebrates, this ability is directly related to their physiological capability (e.g. oxygen stores). we studied the seasonal variation in oxygen stores, body temperature and body condition in california sea lions (zalophus californianus) (csl) as a function of seasonal variation in temperature, primary productivity, diving behavior and reproductive stage. during summer, blood oxygen stores were significantly greater and ...	2012	22561663
a novel antibody-based biomarker for chronic algal toxin exposure and sub-acute neurotoxicity.	the neurotoxic amino acid, domoic acid (da), is naturally produced by marine phytoplankton and presents a significant threat to the health of marine mammals, seabirds and humans via transfer of the toxin through the foodweb. in humans, acute exposure causes a neurotoxic illness known as amnesic shellfish poisoning characterized by seizures, memory loss, coma and death. regular monitoring for high da levels in edible shellfish tissues has been effective in protecting human consumers from acute da ...	2012	22567140
complete genome sequence of a novel picobirnavirus, otarine picobirnavirus, discovered in california sea lions.	we discovered a novel otarine picobirnavirus in fecal samples of california sea lions. its genome contains a large segment with two open reading frames (orfs), orf1 encoding a putative protein of 163 amino acids with unknown function and orf2 encoding capsid protein, and a small segment with one orf encoding rna-dependent rna polymerase.	2012	22570247
risk factors associated with perianesthetic mortality of stranded free-ranging california sea lions (zalophus californianus) undergoing rehabilitation.	the objective of this study was to identify risk factors associated with perianesthetic mortality of stranded free-ranging california sea lions (zalophus californianus) undergoing rehabilitation. hospital records of california sea lions that underwent heavy sedation or general anesthesia from 2004 through 2008 were reviewed, including records from 419 anesthetic events. procedures that resulted in death during or in the subsequent 72 hr of anesthesia were classified as cases (n = 15). procedures ...	2012	22779225
thoracic auscultation in captive bottlenose dolphins (tursiops truncatus), california sea lions (zalophus californianus), and south african fur seals (arctocephalus pusillus) with an electronic stethoscope.	thoracic auscultation is an important diagnostic method used in cases of suspected pulmonary disease in many species, as respiratory sounds contain significant information on the physiology and pathology of the lungs and upper airways. respiratory diseases are frequent in marine mammals and are often listed as one of their main causes of death. the aim of this study was to investigate and report baseline parameters for the electronic-mediated thoracic auscultation of one cetacean species and two ...	2012	22779229
a retrospective survey of the ocular histopathology of the pinniped eye with emphasis on corneal disease.	a retrospective review of globes from 70 pinnipeds submitted to the comparative ocular pathology laboratory of wisconsin (coplow) describing the type and frequency of ocular disease.	2013	22812701
a cupric silver histochemical analysis of domoic acid damage to olfactory pathways following status epilepticus in a rat model for chronic recurrent spontaneous seizures and aggressive behavior.	the amnesic shellfish toxin, domoic acid, interferes with glutamatergic pathways leading to neuronal damage, most notably causing memory loss and seizures. in this study, the authors utilized a recently developed rat model for domoic acid-induced epilepsy, an emerging disease appearing in california sea lions weeks to months after poisoning, to identify structural damage that may lead to a permanent epileptic state. sprague dawley rats were kindled with several low hourly intraperitoneal doses o ...	2013	22821366
skin histology and its role in heat dissipation in three pinniped species.	pinnipeds have a thick blubber layer and may have difficulty maintaining their body temperature during hot weather when on land. the skin is the main thermoregulatory conduit which emits excessive body heat.	2012	22889205
lung collapse in the diving sea lion: hold the nitrogen and save the oxygen.	lung collapse is considered the primary mechanism that limits nitrogen absorption and decreases the risk of decompression sickness in deep-diving marine mammals. continuous arterial partial pressure of oxygen profiles in a free-diving female california sea lion (zalophus californianus) revealed that (i) depth of lung collapse was near 225 m as evidenced by abrupt changes in during descent and ascent, (ii) depth of lung collapse was positively related to maximum dive depth, suggesting that the se ...	2012	22993241
evaluation of circulating eosinophil count and adrenal gland function in california sea lions naturally exposed to domoic acid.	to determine the effect of natural exposure to domoic acid (da) on eosinophil counts and adrenal gland function in california sea lions (zalophus californianus).	2012	23013509
cryptococcus albidus infection in a california sea lion (zalophus californianus).	sporadic cases of cryptococcosis have been reported in marine mammals, typically due to cryptococcus neoformans and, more recently, to cryptococcus gattii in cetaceans. cryptococcus albidus, a ubiquitous fungal species not typically considered to be pathogenic, was recovered from a juvenile california sea lion (zalophus californianus) rescued near san francisco bay, california. yeast morphologically consistent with a cryptococcus sp. was identified histologically in a lymph node and c. albidus w ...	2012	23060504
mortality related to spotted ratfish (hydrolagus colliei) in pacific harbor seals (phoca vitulina) in washington state.	tissue perforation and penetration by dorsal fin spines of spotted ratfish (hydrolagus colliei) were responsible for the death of seven harbor seals (phoca vitulina) in washington state (usa) between 2006 and 2011. in six animals, necropsy revealed spines or spine parts that had perforated the esophagus or stomach and migrated into vital tissues, resulting in hemothorax, pneumothorax, pleuritis, and peritonitis. in a seventh case, a ratfish spine was recovered from the mouth of a harbor seal eut ...	2012	23060509
characterization of ocular gland morphology and tear composition of pinnipeds.	the importance of tear film integrity to ocular health in terrestrial mammals is well established, however, in marine mammals, the role of the tear film in protection of the ocular surface is not known. in an effort to better understand the function of tears in maintaining health of the marine mammal eye surface, we examined ocular glands of the california sea lion and began to characterize the biochemical nature of the tear film of pinnipeds.	2013	23067374
temporal summation of airborne tones in a california sea lion (zalophus californianus).	the trade-off between sound level and duration on hearing sensitivity (temporal summation) was investigated in a california sea lion (zalophus californianus) using airborne pure-tone stimuli. thresholds were behaviorally measured using the method of constant stimuli at 2.5, 5, and 10 khz for nine signal durations ranging from 25 to 500 ms. in general, thresholds decreased as duration increased up to 300 ms, beyond which thresholds did not significantly improve. when these data were fitted separa ...	2012	23145636
hydrodynamic perception in true seals (phocidae) and eared seals (otariidae).	pinnipeds, that is true seals (phocidae), eared seals (otariidae), and walruses (odobenidae), possess highly developed vibrissal systems for mechanoreception. they can use their vibrissae to detect and discriminate objects by direct touch. at least in phocidae and otariidae, the vibrissae can also be used to detect and analyse water movements. here, we review what is known about this ability, known as hydrodynamic perception, in pinnipeds. hydrodynamic perception in pinnipeds developed convergen ...	2013	23180048
the first report of otarine herpesvirus-1-associated urogenital carcinoma in a south american fur seal (arctocephalus australis).	otarine herpesvirus (othv)-1-associated urogenital carcinoma has been well documented in the california sea lion (zalophus californianus, csl), but this is the first report of this tumour in a captive south american fur seal (arctocephalus australis, safs). the gross and microscopical morphology of the tumour in the safs was identical to that described previously in csls and the tumour in the present case had metastasized within the urogenital tract and draining lymph nodes and to the lungs and ...	2013	23218410
clinical relevance of novel otarine herpesvirus-3 in california sea lions (zalophus californianus): lymphoma, esophageal ulcers, and strandings.	herpesviruses have been recognized in marine mammals, but their clinical relevance is not always easy to assess. a novel otarine herpesvirus-3 (othv3) was detected in a geriatric california sea lion (zalophus californianus), and using a newly developed quantitative pcr assay paired with histology, othv3 was associated with esophageal ulcers and b cell lymphoblastic lymphoma in this animal. the prevalence and quantities of othv3 were then determined among buffy coats from 87 stranded and managed ...	2012	23234600
occurrence of pasteurellaceae bacteria in the oral cavity of selected marine mammal species.	the occurrence of bacteria belonging to pasteurellaceae in the oral cavity of captive marine mammals was investigated using culture and subsequent geno- and phenotypic characterization and phylogenetic analyses. a total of 89 bacterial isolates from pinnipeds tentatively classified with the family pasteurellaceae were further characterized by phylogenetic analysis of rpob gene sequences, which showed that the isolates investigated formed five distinct groups. four strains from california sea lio ...	2012	23272350
the binaural click-evoked auditory brainstem response of the california sea lion (zalophus californianus).	auditory brainstem responses (abrs) elicited by high-amplitude [100 db re 20 μpa, peak-to-peak equivalent sound pressure level (pespl)] aerial broadband clicks were collected from seven california sea lions in order to provide a basic description of short-latency auditory evoked potentials in this species. the waveform of the abr was similar to that of other mammals, comprising seven positive and six negative characteristic waves. variability in the amplitudes and latencies of waves was higher a ...	2013	23297929
gas bubble disease in the brain of a living california sea lion (zalophus californianus).	a yearling california sea lion (zalophus californianus) was admitted into rehabilitation with signs of cerebellar pathology. diagnostic imaging that included radiography and magnetic resonance imaging (mri) demonstrated space-occupying lesions predominantly in the cerebellum that were filled partially by csf-like fluid and partially by gas, and cerebral lesions that were fluid filled. over a maximum period of 4 months, the brain lesions reduced in size and the gas resorbed and was replaced by cs ...	2013	23372553
asymptomatic and chronic carriage of leptospira interrogans serovar pomona in california sea lions (zalophus californianus).	since 1970, periodic outbreaks of leptospirosis, caused by pathogenic spirochetes in the genus leptospira, have caused morbidity and mortality of california sea lions (zalophus californianus) along the pacific coast of north america. yearly seasonal epizootics of varying magnitude occur between the months of july and december, with major epizootics occurring every 3-5 years. genetic and serological data suggest that leptospira interrogans serovar pomona is the infecting serovar and is enzootic i ...	2013	23419822
persistent neurological damage associated with spontaneous recurrent seizures and atypical aggressive behavior of domoic acid epileptic disease.	the harmful alga pseudo-nitzschia sp. is the cause of human amnesic shellfish poisoning and the stranding of thousands of sea lions with seizures as a hallmark symptom. a human case study and epidemiological report of hundreds of stranded sea lions found individuals presenting months after recovery with a neurological disease similar to temporal lobe epilepsy. a rat model developed to establish and better predict how epileptic disease results from domoic acid poisoning demonstrated that a single ...	2013	23457124
a california sea lion (zalophus californianus) can keep the beat: motor entrainment to rhythmic auditory stimuli in a non vocal mimic.	is the ability to entrain motor activity to a rhythmic auditory stimulus, that is "keep a beat," dependent on neural adaptations supporting vocal mimicry? that is the premise of the vocal learning and synchronization hypothesis, recently advanced to explain the basis of this behavior (a. patel, 2006, musical rhythm, linguistic rhythm, and human evolution, music perception, 24, 99-104). prior to the current study, only vocal mimics, including humans, cockatoos, and budgerigars, have been shown to ...	2013	23544769
comparative assessment of amphibious hearing in pinnipeds.	auditory sensitivity in pinnipeds is influenced by the need to balance efficient sound detection in two vastly different physical environments. previous comparisons between aerial and underwater hearing capabilities have considered media-dependent differences relative to auditory anatomy, acoustic communication, ecology, and amphibious life history. new data for several species, including recently published audiograms and previously unreported measurements obtained in quiet conditions, necessita ...	2013	23563644
morphometric and molecular characterization of the species of uncinaria frölich, 1789 (nematoda) parasitic in the australian fur seal arctocephalus pusillus doriferus (schreber), with notes on hookworms in three other pinniped hosts.	this study presents morphological and molecular data on hookworms from the australian fur seal arctocephalus pusillus doriferus (schreber) currently identified in australian waters as uncinaria hamiltoni baylis, 1933. additional specimens from the australian sea lion neophoca cinerea (péron) and the new zealand fur seal arctocephalus forsteri (lesson) from australia, and the southern elephant seal mirounga leonina (linnaeus) from antarctica, were included. using the internal transcribed spacer ( ...	2013	23595493
an outbreak of lethal adenovirus infection among different otariid species.	an outbreak of fatal fulminant hepatitis at a japanese aquarium involved 3 otariids: a california sea lion (zalophus californianus), a south african fur seal (arctocephalus pusillus) and a south american sea lion (otaria flavescens). in a span of about a week in february 2012, 3 otariids showed diarrhea and were acutely low-spirited; subsequently, all three animals died within a period of 3 days. markedly increased aspartate amino transferase and alanine amino transferase activities were observe ...	2013	23643878
comparative anatomy of the ophthalmic rete and its relationship to ocular blood flow in three species of marine mammal.	to examine the blood supply to the eyes of bottlenose dolphin (tursiops truncatus), spotted seal (phoca largha), and california sea lion (zalophus californianus). emphasis is placed on exploring the anatomic function in the context of aquatic life.	2014	23742618
ecological, morphological, and molecular studies of acanthocheilonema odendhali (nematoda: filarioidea) in northern fur seals (callorhinus ursinus) on st. paul island, alaska.	studies of northern fur seal (callorhinus ursinus linnaeus, 1758) infection by the filariid nematode acanthocheilonema odendhali were carried out in 2011-2012 on st. paul island, pribilof archipelago, alaska. skins of 502 humanely harvested northern fur seals from haul-out areas of five rookeries, polovina (n = 122), morjovi (n = 54), zapadni (n = 72), lukanin (n = 109), and gorbatch (n = 145), were examined. a. odendhali was found in 18% of northern fur seals. the prevalence of infection ranged ...	2013	23760875
otariodibacter oris and bisgaardia genomospecies 1 isolated from infections in pinnipeds.	we document the first associations of two recently described species of pasteurellaceae bacteria with lesions in wild pinnipeds in rehabilitation. samples were collected from nine lesions in four california sea lions (zalophus californianus) and two pacific harbor seals (phoca vitulina) during necropsy or admission examinations at a rehabilitation facility in northern california. seven pasteurellaceae isolates were identified using phenotypic tests and partial rpob gene sequencing. six strains o ...	2013	23778617
successfully treated dermatomycosis in california sea lions (zalophus californianus).	we describe clinical cases caused by microsporum gypseum in two subadult male california sea lions (zalophus californianus). dermatomycosis is uncommonly reported in pinnipeds, including this species. in these cases, skin lesions were multifocal to coalescing, involved all flippers, and were most pronounced on the ventral surfaces of flippers. they were well-demarcated, depigmented, and covered with crusts. the definitive diagnosis was obtained through microscopic examination and fungal culture ...	2013	23805567
estimation of male gene flow from measures of nuclear and female genetic differentiation.	an approach is provided to estimate male gene flow and the ratio of male to female gene flow, given that there are estimates of diploid, nuclear gene flow and haploid, female gene flow. this approach can be applied to estimates of differentiation (f st ) from biparentally and maternally inherited markers, assuming the equilibrium island model and equal effective numbers of males and females. corrections to formulas used previously for california sea lions (gonzález-suárez m, flatz r, aurioles-ga ...	2013	23894193
effect of angle on flow-induced vibrations of pinniped vibrissae.	two types of vibrissal surface structures, undulated and smooth, exist among pinnipeds. most phocidae have vibrissae with undulated surfaces, while otariidae, odobenidae, and a few phocid species possess vibrissae with smooth surfaces. variations in cross-sectional profile and orientation of the vibrissae also exist between pinniped species. these factors may influence the way that the vibrissae behave when exposed to water flow. this study investigated the effect that vibrissal surface structur ...	2013	23922834
insights from venous oxygen profiles: oxygen utilization and management in diving california sea lions.	the management and depletion of o2 stores underlie the aerobic dive capacities of marine mammals. the california sea lion (zalophus californianus) presumably optimizes o2 store management during all dives, but approaches its physiological limits during deep dives to greater than 300 m depth. blood o2 comprises the largest component of total body o2 stores in adult sea lions. therefore, we investigated venous blood o2 depletion during dives of california sea lions during maternal foraging trips t ...	2013	23926312
[genomic characteristics of bocavirus and molecular mechanism of its pathogenicity--a review].	bocavirus was considered as a member of the subfamily parvoviriae of the family parvoviridae, which includes bovine bocavirus, minute virus of canines, human bocavirus, as well as the newly identified swine bocavirus, gorilla bocavirus, feline bocavirus, canine bocavirus and bocavirus identified in california sea lion sample. at present, as an emerging pathogen, bocavirus members attract great attention by researchers worldwide. we reviewed published papers in combination with our study for seve ...	2013	23957145
microbes, metagenomes and marine mammals: enabling the next generation of scientist to enter the genomic era.	the revolution in dna sequencing technology continues unabated, and is affecting all aspects of the biological and medical sciences. the training and recruitment of the next generation of researchers who are able to use and exploit the new technology is severely lacking and potentially negatively influencing research and development efforts to advance genome biology. here we present a cross-disciplinary course that provides undergraduate students with practical experience in running a next gener ...	2013	24007365
oxidative stress and redistribution of glutamine synthetase in california sea lions (zalophus californianus) with domoic acid toxicosis.	the aim of this study was to test the hypothesis that oxidative stress and glutamine synthetase (gs) redistribution occur in domoic acid (da) toxicosis in california sea lions (csls, zalophus californianus). sections of archived hippocampi from seven control and 13 csls diagnosed with da toxicosis were labelled immunohistochemically for gs and for two markers of oxidative stress, malondialdehyde (mda) and 3-nitrotyrosine (nt). the distribution and intensity of labelling were compared with the pa ...	2014	24060152
pharmacokinetics of ceftiofur crystalline-free acid (excede sterile suspension) administered via intramuscular injection in wild california sea lions (zalophus californianus).	the pharmacokinetics of ceftiofur crystalline-free acid (excede sterile suspension, 200 mg ceftiofur equivalents/ml) were determined for the california sea lion (zalophus californianus). a single dose of excede was administered intramuscularly at 6.6 mg/kg to 12 wild california sea lions during rehabilitation. the first 10 animals were each assigned to two blood collection time points, with a total of 10 time points at: 6, 12, 24, 48, 72, 96, 120, 144, 168, and 192 hr after administration of the ...	2013	24063100
comparative study of notoungulate (placentalia, mammalia) bony labyrinths and new phylogenetically informative inner ear characters.	the phylogenetic relationships of notoungulates, an extinct group of predominantly south american herbivores, remain poorly resolved with respect to both other placental mammals and among one another. most previous phylogenetic analyses of notoungulates have not included characters of the internal cranium, not least because few such features, including the bony labyrinth, have been described for members of the group. here we describe the inner ears of the notoungulates altitypotherium chucalensi ...	2013	24102069
molecular systematics of pinniped hookworms (nematoda: uncinaria): species delimitation, host associations and host-induced morphometric variation.	hookworms of the genus uncinaria have been widely reported from juvenile pinnipeds, however investigations of their systematics has been limited, with only two species described, uncinaria lucasi from northern fur seals (callorhinus ursinus) and uncinaria hamiltoni from south american sea lions (otaria flavescens). hookworms were sampled from these hosts and seven additional species including steller sea lions (eumetopias jubatus), california sea lions (zalophus californianus), south american fu ...	2013	24162075
behavioral responses of california sea lions to mid-frequency (3250-3450 hz) sonar signals.	military sonar has the potential to negatively impact marine mammals. to investigate factors affecting behavioral disruption in california sea lions (zalophus californianus), fifteen sea lions participated in a controlled exposure study using a simulated tactical sonar signal (1 s duration, 3250-3450 hz) as a stimulus. subjects were placed into groups of three and each group received a stimulus exposure of 125, 140, 155, 170, or 185 db re: 1 μpa (rms). each subject was trained to swim across an ...	2013	24183102
rhythmic cognition in humans and animals: distinguishing meter and pulse perception.	this paper outlines a cognitive and comparative perspective on human rhythmic cognition that emphasizes a key distinction between pulse perception and meter perception. pulse perception involves the extraction of a regular pulse or "tactus" from a stream of events. meter perception involves grouping of events into hierarchical trees with differing levels of "strength", or perceptual prominence. i argue that metrically-structured rhythms are required to either perform or move appropriately to mus ...	2013	24198765
cross-modal transitivity in a california sea lion (zalophus californianus).	the ability of an experimentally experienced female california sea lion to form transitive relations across sensory modalities was tested using a matching-to-sample procedure. the subject was trained by trial-and-error, using differential reinforcement, to relate an acoustic sample stimulus to one member from each of two previously established visual classes. once the two auditory-visual relations were formed, she was tested to determine whether untrained transitive relations would emerge betwee ...	2014	24337783
hippocampal neuropathology of domoic acid-induced epilepsy in california sea lions (zalophus californianus).	california sea lions (zalophus californianus) are abundant human-sized carnivores with large gyrencephalic brains. they develop epilepsy after experiencing status epilepticus when naturally exposed to domoic acid. we tested whether sea lions previously exposed to da (chronic da sea lions) display hippocampal neuropathology similar to that of human patients with temporal lobe epilepsy. hippocampi were obtained from control and chronic da sea lions. stereology was used to estimate numbers of nissl ...	2014	24638960
domoic acid epileptic disease.	domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. the potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in quebec, and was characterized as a chronic epileptic syndrome in california sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. the sea lion study provided a breadth of insight ...	2014	24663110
dental pathology of the california sea lion (zalophus californianus).	skulls from 1,085 california sea lions (zalophus californianus) were examined macroscopically according to defined criteria. the museum specimens, 61.8% male and 37.3% female, were acquired from strandings and varied in age from juvenile to adult. the majority of teeth were available for examination (95.7%); 3.8% of teeth were artefactually absent, 0.4% deemed absent due to acquired tooth loss and 0.1% were congenitally absent. acquired tooth loss was associated significantly with sex (p = 0.004 ...	2014	24725510
senile plaques and cerebral amyloid angiopathy in an aged california sea lion (zalophus californianus).	senile plaques (sps) and cerebral amyloid angiopathy (caa) consisting of β-amyloid (aβ) are major features in the brain of alzheimer's disease (ad) patients and elderly humans and animals. in this study, we report the finding of sps and caa in an aged sea lion (30 years), which is the first demonstration of ad-related pathological changes in a marine animal. histologically, sps were observed at the cerebral cortex, most frequently at the frontal lobe, with two morphologically different types: th ...	2014	24779910
deep-diving sea lions exhibit extreme bradycardia in long-duration dives.	heart rate and peripheral blood flow distribution are the primary determinants of the rate and pattern of oxygen store utilisation and ultimately breath-hold duration in marine endotherms. despite this, little is known about how otariids (sea lions and fur seals) regulate heart rate (fh) while diving. we investigated dive fh in five adult female california sea lions (zalophus californianus) during foraging trips by instrumenting them with digital electrocardiogram (ecg) loggers and time depth re ...	2014	24790100
trihalomethanes in marine mammal aquaria: occurrences, sources, and health risks.	disinfecting water containing the high levels of dissolved organic carbon (doc) commonly generated during pinniped husbandry may cause the formation of carcinogenic disinfection byproducts (dbps). little information is available on dbp levels, sources, and health risks in marine mammal aquaria. using the commonly observed trihalomethanes (thms) as a dbp indicator, we monitored concentrations for seven months at the marine mammal center in sausalito, california, one of the largest pinniped rehabi ...	2014	24805374
isolation of leptospira from a phocid: acute renal failure and mortality from leptospirosis in rehabilitated northern elephant seals (mirounga angustirostris), california, usa.	during rehabilitation, acute renal failure due to leptospirosis occurred in eight male northern elephant seals (mirounga angustirostris) that stranded along the central california coast in 2011. characteristic histologic lesions including renal tubular degeneration, necrosis, and mineralization, and mild lymphoplasmacytic interstitial nephritis were noted in the six animals examined. immunohistochemistry, bacterial culture, and pcr were positive in 2/3, 2/3, and 3/4 seals, respectively, and 6/8 ...	2014	24807176
development, comparison, and validation using elisas for the determination of domoic acid in california sea lion body fluids.	mortalities of california sea lions (zalophus californianus) attributed to the neurotoxin domoic acid (da) produced by the diatom pseudo-nitzschia have occurred repeatedly along the u.s. west coast since the late 1990s. quantifying the amount of da in these animals and correlating this information with the presence of da in phytoplankton and the local food web has become a research focus for many scientists. however, differences in materials, equipment, technical capability, budgets, and objecti ...	2014	24830146
interactions of marine mammals and birds with offshore membrane enclosures for growing algae (omega).	omega is an integrated aquatic system to produce biofuels, treat and recycle wastewater, capture co2, and expand aquaculture production. this system includes floating photobioreactors (pbrs) that will cover hundreds of hectares in marine bays. to assess the interactions of marine mammals and birds with pbrs, 9 × 1.3 m flat panel and 9.5 × 0.2 m tubular pbrs were deployed in a harbor and monitored day and night from october 10, 2011 to janurary 22, 2012 using infrared video. to observe interactio ...	2014	24955238
infection of california sea lions (zalophus californianus) with terrestrial brucella spp.	infections with brucella ceti and pinnipedialis are prevalent in marine mammals worldwide. a total of 22 california sea lions (zalophus californianus) were examined to determine their exposure to brucella spp. at san esteban island in the gulf of california, mexico, in june and july 2011. although samples of blood, vaginal mucus and milk cultured negative for these bacteria, the application of rose bengal, agar gel immunodiffusion, pcr and modified fluorescence polarization assays found that fiv ...	2014	25066000
development of a real-time pcr for the detection of pathogenic leptospira spp. in california sea lions.	several real-time pcr assays are currently used for detection of pathogenic leptospira spp.; however, few methods have been described for the successful evaluation of clinical urine samples. this study reports a rapid assay for the detection of pathogenic leptospira spp. in california sea lions zalophus californianus using real-time pcr with primers and a probe targeting the lipl32 gene. the pcr assay had high analytic sensitivity-the limit of detection was 3 genome copies per pcr volume using l ...	2014	25114040
characterisation of whisker control in the california sea lion (zalophus californianus) during a complex, dynamic sensorimotor task.	studies in pinniped whisker use have shown that their whiskers are extremely sensitive to tactile and hydrodynamic signals. while pinnipeds position their whiskers on to objects and have some control over their whisker protractions, it has always been thought that head movements are more responsible for whisker positioning than the movement of the whiskers themselves. this study uses ball balancing, a dynamic sensorimotor skill that is often used in human and robotic coordination studies, to pro ...	2014	25138923
object permanence in marine mammals using the violation of expectation procedure.	object permanence refers to the ability to process information about objects even when they are not visible. one stage of object permanence, called visible displacement, involves being able to find an object that has been fully hidden from view. visible displacement has been demonstrated in many animal species, yet very little is known about object permanence in marine mammals. in addition, the methodology for testing visible displacement has sometimes been called into question because alternati ...	2015	25193351
auditory detection of ultrasonic coded transmitters by seals and sea lions.	ultrasonic coded transmitters (ucts) are high-frequency acoustic tags that are often used to conduct survivorship studies of vulnerable fish species. recent observations of differential mortality in tag control studies suggest that fish instrumented with ucts may be selectively targeted by marine mammal predators, thereby skewing valuable survivorship data. in order to better understand the ability of pinnipeds to detect uct outputs, behavioral high-frequency hearing thresholds were obtained fro ...	2014	25234996
sesavirus: prototype of a new parvovirus genus in feces of a sea lion.	we describe the nearly complete genome of a highly divergent parvovirus, we tentatively name sesavirus, from the feces of a california sea lion pup (zalophus californianus) suffering from malnutrition and pneumonia. the 5,049-base-long genome contained two major orfs encoding a 553-aa nonstructural protein and a 965-aa structural protein which shared closest amino acid identities of 25 and 28 %, respectively, with members of the copiparvovirus genus known to infect pigs and cows. given the low d ...	2015	25272961
molecular epidemiology of cryptosporidium spp. and giardia spp. in mussels (mytilus californianus) and california sea lions (zalophus californianus) from central california.	cryptosporidium and giardia are of public health importance, with recognized transmission through recreational waters. therefore, both can contaminate marine waters and shellfish, with potential to infect marine mammals in nearshore ecosystems. a 2-year study was conducted to evaluate the presence of cryptosporidium and giardia in mussels located at two distinct coastal areas in california, namely, (i) land runoff plume sites and (ii) locations near sea lion haul-out sites, as well as in feces o ...	2014	25281384
domoic acid-induced seizures in california sea lions (zalophus californianus) are associated with neuroinflammatory brain injury.	california sea lions (csls) exposed to the marine biotoxin domoic acid (da) develop an acute or chronic toxicosis marked by seizures and act as sentinels of the disease. experimental evidence suggests that oxidative stress and neuroinflammation are important mechanisms underlying the seizurogenic potential of environmental toxicants but these pathways are relatively unstudied in csls. in the current study, we investigated the role of glutamate-glutamine changes and gliosis in da-exposed csls to ...	2014	25286249
prevalence and characterization of salmonella shed by captive and free-range california sea lions (zalophus californianus) from a rehabilitation center and three state reserves along the california coast.	salmonella is a genus of zoonotic bacteria that can infect a variety of animals, and may cause gastrointestinal disease in marine mammals. many of the same salmonella serotypes are shed by california sea lions (zalophus californianus) and humans, which poses transmission questions and public health concerns. in this study, 454 fecal samples from three free-ranging california sea lion populations along the california coast and from animals undergoing rehabilitation at the marine mammal center, sa ...	2014	25314819