scholarly journals Social associations between California sea lions influence the use of a novel foraging ground

2017 ◽  
Vol 4 (5) ◽  
pp. 160820 ◽  
Author(s):  
Zachary A. Schakner ◽  
Matthew B. Petelle ◽  
Mathew J. Tennis ◽  
Bjorn K. Van der Leeuw ◽  
Robert T. Stansell ◽  
...  
Keyword(s):  
Social Network ◽  
Social Relationships ◽  
Columbia River ◽  
Foraging Success ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Sea Lions ◽  
Salmon Recovery ◽  
Network Position ◽  
Social Associations

Social relationships define an individual's position in its social network, which can influence the acquisition and spread of information and behavioural variants through the population. Thus, when nuisance behaviours spread through wildlife populations, identifying central individuals may provide valuable insights for problem-species management. We studied the effects of network position on California sea lion ( Zalophus californianus ) discovery and foraging success at a novel foraging ground—the salmonids that aggregate at the Bonneville Dam tail-race, 235 km up the Columbia River. We found that an individual's centrality in their social network influenced discovery of the Bonneville Dam and whether they returned the next year. Foraging success once at the dam was independent of network position. Extensive lethal and non-lethal removal efforts have been implemented at Bonneville Dam and focused on reducing the number of individual sea lions at the dam. Since social relationships forged at the opening of the Columbia River influence both the discovery and return to the Bonneville Dam, efforts to increase salmon recovery may be enhanced by breaking apart social networks at the opening of the river.

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.

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

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.

scholarly journals Social networks predict patch discovery in a wild population of songbirds

2012 ◽  
Vol 279 (1745) ◽  
pp. 4199-4205 ◽  
Author(s):  
L. M. Aplin ◽  
D. R. Farine ◽  
J. Morand-Ferron ◽  
B. C. Sheldon
Keyword(s):  
Social Network ◽  
Wild Population ◽  
Social Information ◽  
Social Connections ◽  
Novel Food ◽  
Network Position ◽  
Diffusion Analysis ◽  
The Social ◽  
Social Information Use ◽  
Social Associations

Animals use social information in a wide variety of contexts. Its extensive use by individuals to locate food patches has been documented in a number of species, and various mechanisms of discovery have been identified. However, less is known about whether individuals differ in their access to, and use of, social information to find food. We measured the social network of a wild population of three sympatric tit species (family Paridae) and then recorded individual discovery of novel food patches. By using recently developed methods for network-based diffusion analysis, we show that order of arrival at new food patches was predicted by social associations. Models based only on group searching did not explain this relationship. Furthermore, network position was correlated with likelihood of patch discovery, with central individuals more likely to locate and use novel foraging patches than those with limited social connections. These results demonstrate the utility of social network analysis as a method to investigate social information use, and suggest that the greater probability of receiving social information about new foraging patches confers a benefit on more socially connected individuals.

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.

Movements of Male California Sea Lions Captured in the Columbia River

2010 ◽  
Vol 84 (1) ◽  
pp. 60-72 ◽  
Author(s):  
Bryan E. Wright ◽  
Mathew J. Tennis ◽  
Robin F. Brown
Keyword(s):  
Columbia River ◽  
California Sea Lions ◽  
Sea Lions

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.

Extraverts Have Larger Social Network Layers

2011 ◽  
Vol 32 (3) ◽  
pp. 161-169 ◽  
Author(s):  
Thomas V. Pollet ◽  
Sam G. B. Roberts ◽  
Robin I. M. Dunbar
Keyword(s):  
Social Network ◽  
Social Relationships ◽  
Outer Layer ◽  
Network Size ◽  
Emotional Intensity ◽  
Emotional Closeness ◽  
Network Layer ◽  
Network Layers ◽  
Social Network Size

Previous studies showed that extraversion influences social network size. However, it is unclear how extraversion affects the size of different layers of the network, and how extraversion relates to the emotional intensity of social relationships. We examined the relationships between extraversion, network size, and emotional closeness for 117 individuals. The results demonstrated that extraverts had larger networks at every layer (support clique, sympathy group, outer layer). The results were robust and were not attributable to potential confounds such as sex, though they were modest in size (raw correlations between extraversion and size of network layer, .20 < r < .23). However, extraverts were not emotionally closer to individuals in their network, even after controlling for network size. These results highlight the importance of considering not just social network size in relation to personality, but also the quality of relationships with network members.

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