CYTOGENETIC COMPARISON OF SOME PINNIPEDS (MAMMALIA: EUTHERIA)

1967 ◽  
Vol 45 (5) ◽  
pp. 773-778 ◽  
Author(s):  
F. H. Fay ◽  
V. R. Rausch ◽  
E. T. Feltz
Keyword(s):  
Harbor Seal ◽  
Weddell Seal ◽  
Ringed Seal ◽  
Sea Lion ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Weddell Seals ◽  
Sea Lions ◽  
Fur Seal ◽  
Pusa Hispida

Karyotypes of the harbor seal, Phoca vitulina (2N = 32), the bearded seal, Erignathus barbatus (2N = 34), the Weddell seal, Leptonychotes weddelli (2N = 34), the walrus, Odobenus rosmarus (2N = 32), the Steller sea lion, Eumetopias jubata (2N = 36), and the northern fur seal, Callorhinus ursinus (2N = 36), are described and compared with those of the ringed seal, Pusa hispida, and California sea lion, Zalophus californianus, reported by other workers. These are discussed with reference to current theories of pinniped phylogeny and systematics. The number and morphology of chromosomes in these eight species, representing each family and subfamily of pinnipeds, were found to be remarkably similar. This is interpreted as evidence of close interrelationship, commensurate with the theory of monophyletic origin. Karyograms of the harbor seal and ringed seal are virtually identical, as are those of the bearded and Weddell seals and those of the Steller and California sea lions. The karyotype of the fur seal is similar to the sea lions', while that of the walrus resembles the phocids' in some ways and the otariids' in others. A need for thorough comparative studies and reappraisal of pinniped systematics at the subfamilial and generic levels is indicated.

Quantifying errors associated with using fecal samples to determine the diet of the California sea lion (Zalophus californianus)

2001 ◽  
Vol 79 (6) ◽  
pp. 1080-1087 ◽  
Author(s):  
Anthony J Orr ◽  
James T Harvey
Keyword(s):  
Zalophus Californianus ◽  
Correction Factors ◽  
Sea Lion ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Fecal Samples ◽  
Sea Lions ◽  
Mesh Bag ◽  
Estimate Number ◽  
Fish Otoliths

The purpose of this study was to quantify the errors associated with using fecal samples to determine the diet of the California sea lion (Zalophus californianus). Fishes and squids of known size and number were fed to five sea lions held in enclosures with seawater-filled pools. Enclosures were washed and pools were drained periodically so that sea lion feces could be collected using a 0.5 mm mesh bag. Fish otoliths and squid beaks were collected from feces and used to estimate number and size of prey eaten. An average of 50.7% (SE = 6.4%) of 430 fishes and 73.5% (SE = 12.0%) of 49 cephalopods fed to sea lions were represented by otoliths and beaks in feces, respectively. Estimated lengths of fish from feces were less than lengths of fish fed to sea lions by an average of 30.1% (SE = 2.8%). Beaks were not digested significantly; estimated lengths of squid were underestimated by an average of only 3.3% (SE = 1.5%) relative to actual lengths. Passage rates of otoliths varied, but more than 70% were recovered within 48 h after the fish was consumed. Passage rates of beaks were generally less than those of otoliths; six beaks (11%) were collected in feces 4 days after the squid were eaten. Correction factors were created to more reliably estimate the number and size of fishes and cephalopods eaten by California sea lions.

Development, Comparison, and Validation Using ELISAs for the Determination of Domoic Acid in California Sea Lion Body Fluids

2014 ◽  
Vol 97 (2) ◽  
pp. 345-355 ◽  
Author(s):  
Erica L Seubert ◽  
Meredith D A Howard ◽  
Raphael M Kudela ◽  
Thomas N Stewart ◽  
R Wayne Litaker ◽  
...  
Keyword(s):  
Domoic Acid ◽  
Matrix Effects ◽  
Body Fluids ◽  
Sea Lion ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Sea Lions ◽  
Technical Capability ◽  
Analytical Platforms

Abstract 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 objectives of the various groups and/or agencies involved in this work have influenced the DAquantification platforms used. The goal of the present study was to compare the performance of two commercially available ELISAs for the determination of DAin a spectrum of California sea lion body fluids andto compare the results with LC/MS of the same samples. The results indicated differences among these approaches, presumably owing to matrix effects (particularly urine) and antibody reactivities. This information implies that care should be taken in attemptingto compare datasets generated using different analytical platforms and interpreting the results of published studies.

Verminous Pneumonia in the California Sea Lion (Zalophus californianus)

1970 ◽  
Vol 7 (2) ◽  
pp. 89-101 ◽  
Author(s):  
Robert W. Fleischman ◽  
Robert A. Squire
Keyword(s):  
Bronchial Epithelium ◽  
Zalophus Californianus ◽  
Gastric Ulcers ◽  
Sea Lion ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Sea Lions ◽  
Verminous Pneumonia ◽  
Liver Flukes ◽  
Underlying Pathogenesis

Verminous bronchitis and pneumonia due to Parafiaroides decorus infection is described in California sea lions ( Zalapbus californianus). Marked edema and multiple nodules occurred throughout the lungs. Histologically, both intact and degenerate lungworms occurred and the inflammatory response was pleomophic. A hyaline eosinophilic structure occurring beneath the tracheal and bronchial epithelium was morphologically similar to a structure seen in several human pulmonary diseases. Hypersensitivity may have been important in the underlying pathogenesis of This disease. Liver flukes ( Zalophotrema hepaaticum) and gastric ulcers containing nematodes ( Contraceacum osculalum) occurred in several animals.

scholarly journals Common cancer in a wild animal: the California sea lion ( Zalophus californianus ) as an emerging model for carcinogenesis

2015 ◽  
Vol 370 (1673) ◽  
pp. 20140228 ◽  
Author(s):  
Helen M. Browning ◽  
Frances M. D. Gulland ◽  
John A. Hammond ◽  
Kathleen M. Colegrove ◽  
Ailsa J. Hall
Keyword(s):  
Marine Mammals ◽  
Wild Animal ◽  
Zalophus Californianus ◽  
Sea Lion ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Sea Lions ◽  
Terrestrial Mammals ◽  
The Usa ◽  
Urogenital Carcinoma

Naturally occurring cancers in non-laboratory species have great potential in helping to decipher the often complex causes of neoplasia. Wild animal models could add substantially to our understanding of carcinogenesis, particularly of genetic and environmental interactions, but they are currently underutilized. Studying neoplasia in wild animals is difficult and especially challenging in marine mammals owing to their inaccessibility, lack of exposure history, and ethical, logistical and legal limits on experimentation. Despite this, California sea lions ( Zalophus californianus ) offer an opportunity to investigate risk factors for neoplasia development that have implications for terrestrial mammals and humans who share much of their environment and diet. A relatively accessible California sea lion population on the west coast of the USA has a high prevalence of urogenital carcinoma and is regularly sampled during veterinary care in wildlife rehabilitation centres. Collaborative studies have revealed that genotype, persistent organic pollutants and a herpesvirus are all associated with this cancer. This paper reviews research to date on the epidemiology and pathogenesis of urogenital carcinoma in this species, and presents the California sea lion as an important and currently underexploited wild animal model of carcinogenesis.

scholarly journals New Records on Acanthocephalans from California Sea Lions Zalophus californianus (Pinnipedia, Otariidae) from California, USA

2018 ◽  
Vol 52 (3) ◽  
pp. 181-192 ◽  
Author(s):  
O. I. Lisitsyna ◽  
O. Kudlai ◽  
T. R. Spraker ◽  
T. A. Kuzmina
Keyword(s):  
New Records ◽  
Age Groups ◽  
Zalophus Californianus ◽  
Adult Males ◽  
Sea Lion ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Sea Lions ◽  
Males And Females ◽  
First Time

Abstract To increase the currently limited knowledge addressing acanthocephalans parasitizing California sea lions (Zalophus californianus), 33 animals including pups, juvenile and adult males and females from the Marine Mammal Center (TMMC), Sausalito, California, USA were examined. Totally, 2,268 specimens of acanthocephalans representing five species from the genera Andracantha (A. phalacrocoracis and Andracantha sp.), Corynosoma (C. strumosum and C. obtuscens) and Profilicollis (P. altmani) were found. Profilicollis altmani and A. phalacrocoracis, predominantly parasitize fish-eating birds; they were registered in Z. californianus for the first time. Prevalence and intensity of California sea lion infection and transmission of acanthocephalans in these hosts of different age groups were analyzed and discussed. We provide brief morphological descriptions of the five species of acanthocephalan found in California sea lions.

Pupillometry in seals and sea lions: ecological implications

1997 ◽  
Vol 75 (12) ◽  
pp. 2050-2057 ◽  
Author(s):  
David Hendrik Levenson ◽  
Ronald J. Schusterman
Keyword(s):  
Sensory Modality ◽  
Maximum Size ◽  
Harbor Seal ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Sea Lion ◽  
Northern Elephant Seal ◽  
California Sea Lion ◽  
Sea Lions ◽  
Light Levels

Phocid and otariid pinnipeds forage almost exclusively under water, where observing them is difficult. As a result, little is known of how their senses are used while diving to locate and capture prey. In this study we used pupillometric methods to describe the relative visual abilities of three pinniped species: the northern elephant seal (Mirounga angustirostris), the harbor seal (Phoca vitulina), and the California sea lion (Zalophus californianus). The range of pupillary area and lower limit of pupillary adjustment were determined for each species. The northern elephant seal exhibited the largest range of pupillary area of the species examined. Furthermore, the elephant seal's pupil was found to reach maximum size only under extremely dim conditions. Both the harbor seal and California sea lion exhibited maximum pupillary dilation in conditions several log units brighter. These results indicate that the elephant seal's visual system is designed to function in dimmer conditions and to respond to greater changes in light levels than those of the harbor seal and sea lion. Such findings support the hypothesis that the visual systems of these pinnipeds are adapted for use in their respective foraging environments, and thus suggest that the visual sense is probably an important sensory modality used to locate and capture prey while diving.

scholarly journals Evidence for a genetic basis of urogenital carcinoma in the wild California sea lion

2014 ◽  
Vol 281 (1796) ◽  
pp. 20140240 ◽  
Author(s):  
Helen M. Browning ◽  
Karina Acevedo-Whitehouse ◽  
Frances M. D. Gulland ◽  
Ailsa J. Hall ◽  
Jeanie Finlayson ◽  
...  
Keyword(s):  
California Sea Lions ◽  
California Sea Lion ◽  
Gene Encoding ◽  
Sea Lions ◽  
Wildlife Species ◽  
Large Gene ◽  
In The Wild ◽  
Urogenital Carcinoma ◽  
Control Study ◽  
Individual Locus

Although neoplasia is a major cause of mortality in humans and domestic animals, it has rarely been described in wildlife species. One of the few examples is a highly prevalent urogenital carcinoma in California sea lions (CSLs). Although the aetiology of this carcinoma is clearly multifactorial, inbreeding depression, as estimated using levels of microsatellite multilocus heterozygosity, is identified as predictive for this neoplasia. On further analysis, this relationship appears to be largely driven by one marker, suggesting that a single locus might be associated with the occurrence of this disease in CSLs. In a case–control study, carcinoma was significantly associated with homozygosity at the Pv11 microsatellite locus. Pv11 was mapped to intron 9 of the heparanase 2 gene ( HPSE2 ) locus, a very large gene encoding heparanase 2, which in humans is associated with multiple carcinomas. Correspondingly, immunohistochemical labelling in tissues was present in carcinoma cases within a single homozygous Pv11 genotype. To our knowledge, this is the first report of an individual locus being associated with cancer in any wildlife species. This adds emphasis to the study of HPSE2 in other species, including humans and will guide future studies on this sentinel species that shares much of its diet and environment with humans

scholarly journals Epidemiological models to control the spread of information in marine mammals

2016 ◽  
Vol 283 (1844) ◽  
pp. 20162037 ◽  
Author(s):  
Zachary A. Schakner ◽  
Michael G. Buhnerkempe ◽  
Mathew J. Tennis ◽  
Robert J. Stansell ◽  
Bjorn K. van der Leeuw ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Foraging Behaviour ◽  
Social Transmission ◽  
Sea Lion ◽  
California Sea Lions ◽  
Sea Lions ◽  
Promising Tool ◽  
Diffusion Analysis ◽  
And Control ◽  
The Impact

Socially transmitted wildlife behaviours that create human–wildlife conflict are an emerging problem for conservation efforts, but also provide a unique opportunity to apply principles of infectious disease control to wildlife management. As an example, California sea lions ( Zalophus californianus ) have learned to exploit concentrations of migratory adult salmonids below the fish ladders at Bonneville Dam, impeding endangered salmonid recovery. Proliferation of this foraging behaviour in the sea lion population has resulted in a controversial culling programme of individual sea lions at the dam, but the impact of such culling remains unclear. To evaluate the effectiveness of current and alternative culling strategies, we used network-based diffusion analysis on a long-term dataset to demonstrate that social transmission is implicated in the increase in dam-foraging behaviour and then studied different culling strategies within an epidemiological model of the behavioural transmission data. We show that current levels of lethal control have substantially reduced the rate of social transmission, but failed to effectively reduce overall sea lion recruitment. Earlier implementation of culling could have substantially reduced the extent of behavioural transmission and, ultimately, resulted in fewer animals being culled. Epidemiological analyses offer a promising tool to understand and control socially transmissible behaviours.

Phylogeography of California and Galápagos sea lions and population structure within the California sea lion

2009 ◽  
Vol 156 (7) ◽  
pp. 1375-1387 ◽  
Author(s):  
Yolanda Schramm ◽  
S. L. Mesnick ◽  
J. de la Rosa ◽  
D. M. Palacios ◽  
M. S. Lowry ◽  
...  
Keyword(s):  
Population Structure ◽  
Sea Lion ◽  
California Sea Lion ◽  
Sea Lions
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