Homing by released captive California sea lions, Zalophus californianus, following release on distant islands

1985 ◽  
Vol 63 (9) ◽  
pp. 2162-2164 ◽  
Author(s):  
S. H. Ridgway ◽  
C. C. Robison
Keyword(s):  
San Diego ◽  
Zalophus Californianus ◽  
Sea Lion ◽  
California Sea Lions ◽  
San Nicolas Island ◽  
Sea Lions ◽  
San Diego Bay ◽  
East West ◽  
San Clemente Island

Captive male California sea lions were twice flown to offshore breeding islands and released. Three animals returned to their pen in San Diego Bay after discharge on San Clemente Island, about 115 km away. Two of four returned to the same facility from San Nicolas Island, about 240 km away. The fastest sea lion returned in 2 days from San Clemente and in 4 days from San Nicolas. This is the first evidence for such specific east–west navigation by sea lions and suggests that these animals are good navigators.

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 Persistent Contaminants and Herpesvirus OtHV1 Are Positively Associated With Cancer in Wild California Sea Lions (Zalophus californianus)

2020 ◽  
Vol 7 ◽  
Author(s):  
Frances M. D. Gulland ◽  
Ailsa J. Hall ◽  
Gina M. Ylitalo ◽  
Kathleen M. Colegrove ◽  
Tenaya Norris ◽  
...  
Keyword(s):  
Zalophus Californianus ◽  
Relative Importance ◽  
Ethical Challenges ◽  
Sea Lion ◽  
California Sea Lions ◽  
Contaminant Exposure ◽  
Control Approach ◽  
Sea Lions ◽  
Cancer Occurrence ◽  
Urogenital Carcinoma

The prevalence of cancer in wild California sea lions (Zalophus californianus) is one of the highest amongst mammals, with 18–23% of adult animals examined post-mortem over the past 40 years having urogenital carcinoma. To date, organochlorines, genotype and infection with Otarine herpesvirus-1 (OtHV-1) have been identified in separate studies using distinct animals as associated with this carcinoma. Multi-year studies using large sample sizes to investigate the relative importance of multiple factors on marine mammal health are rare due to logistical and ethical challenges. The objective of this study was to use a case control approach with samples from 394 animals collected over 20 years in a multifactorial analysis to explore the relative importance of distinct factors identified to date as associated with sea lion cancer in the likelihood of sea lion carcinoma. Stepwise regression indicated that the best model to explain carcinoma occurrence included herpesvirus status, contaminant exposure, and blubber depth, but not genotype at a single microsatellite locus, PV11. The odds of carcinoma was 43.57 times higher in sea lions infected with OtHV-1 (95% CI 14.61, 129.96, p < 0.001), and 1.48 times higher for every unit increase in the loge[contaminant concentrations], ng g–1 (an approximate tripling of concentration), in their blubber (95% CI 1.11, 1.97, p < 0.007), after controlling for the effect of blubber depth. These findings demonstrate the importance of contaminant exposure combined with OtHV1 infection, in the potential for cancer occurrence in wild sea lions.

scholarly journals Can Sea Lions’ (Zalophus californianus) Use Mirrors to Locatean Object?

2015 ◽  
Vol 28 ◽  
Author(s):  
Heather M. Hill ◽  
Krista Webber ◽  
Alicia Kemery ◽  
Melissa Garcia ◽  
Stan A. Kuczaj II
Keyword(s):  
Three Dimensional ◽  
Zalophus Californianus ◽  
Sea Lion ◽  
California Sea Lions ◽  
Sea Lions ◽  
Self Recognition ◽  
Novel Objects ◽  
Dimensional Object ◽  
Physical Features ◽  
First Time

Although California sea lions (Zalophus californianus) are capable of forming complex mental concepts, they have failed to demonstrate mirror self-recognition, a skill that requires both a mental representation of one’s physical features and knowledge of a reflective surface. Many non-human species that do not recognize themselves in mirrors can nonetheless learn to use mirror reflections to locate and retrieve objects. A total of 7 sea lions housed at 2 separate facilities were tested on their ability to detect an object using a mirror. The results of a preliminary detection task in which sea lions were reinforced for looking at a mirror to locate an object suggested that 4 sea lions reliably learned to locate an object positioned below a mirror in one of three locations. A follow-up study was conducted to determine if 3 different sea lions could learn the task without training the animals to use the mirrors. Two of the 3 sea lions located a single object in 1 of the 3 locations statistically above chance when the mirrors were added to the task for the first time. With additional mirror exposure, 1 sea lion successfully achieved 100% accuracy in detecting familiar objects placed in 1 of 3 familiar locations. This sea lion also demonstrated her ability to detect an object via a mirror located in a novel, fourth position with 100% accuracy. When two novel objects were tested with four locations, the sea lion again performed well, detecting the objects 87.5%. The results suggest that sea lions have the ability to use mirrors to locate an object with minimal exposure to a mirror, but likely need additional experience with mirrors to efficiently use the properties of these reflective surfaces and understand that the image is a two-dimensional representation of a three-dimensional object.

Heavy Metal and Chlorinated Hydrocarbon Residues in California Sea Lions (Zalophus californianus californianus)

1975 ◽  
Vol 32 (12) ◽  
pp. 2391-2397 ◽  
Author(s):  
Donald R. Buhler ◽  
Robert R. Claeys ◽  
Bruce R. Mate
Keyword(s):  
Heavy Metal ◽  
Total Mercury ◽  
Chlorinated Hydrocarbons ◽  
Zalophus Californianus ◽  
Sea Lion ◽  
California Sea Lions ◽  
Oregon Coast ◽  
Chlorinated Hydrocarbon ◽  
Sea Lions

Samples of various tissues and organs from healthy California sea lions (Zalophus californianus californianus) and sick animals (apparently with leptospirosis) collected along the central Oregon coast in 1970, 1971, and 1973 were analyzed for total mercury, methylmercury, cadmium, and chlorinated hydrocarbons. Maximum mercury concentrations of 74–170 ppm occurred in sea lion liver, but only 1.6–3.7% of this was present as methylmercury. Cadmium was concentrated primarily in the kidney which contained 7.2–12.0 ppm of the metal. Chlorinated hydrocarbon residues in sea lion fat ranged between 253–475 ppm DDE, and 21.2 and 34.1 ppm PCB. Although mercury, cadmium, and chlorinated hydrocarbon residues in some of the sick sea lions were significantly higher than those present in healthy animals, it is not possible to relate these differences to the onset of leptospirosis.

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.

scholarly journals Molecular Epidemiology of Cryptosporidium spp. and Giardia spp. in Mussels (Mytilus californianus) and California Sea Lions (Zalophus californianus) from Central California

2014 ◽  
Vol 80 (24) ◽  
pp. 7732-7740 ◽  
Author(s):  
A. D. Adell ◽  
W. A. Smith ◽  
K. Shapiro ◽  
A. Melli ◽  
P. A. Conrad
Keyword(s):  
Fluorescent Antibody ◽  
Zalophus Californianus ◽  
Detection Methods ◽  
Coastal Environments ◽  
Sea Lion ◽  
California Sea Lions ◽  
Fecal Samples ◽  
Content Type ◽  
Sea Lions ◽  
Land Runoff

ABSTRACTCryptosporidiumandGiardiaare 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 ofCryptosporidiumandGiardiain 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 of California sea lions (CSL) (Zalophus californianus) by the use of direct fluorescent antibody (DFA) detection methods and PCR with sequence analysis. In this study, 961 individual mussel hemolymph samples, 54 aliquots of pooled mussel tissue, and 303 CSL fecal samples were screened.Giardia duodenalisassemblages B and D were detected in hemolymph from mussels collected near two land runoff plume sites (Santa Rosa Creek and Carmel River), and assemblages C and D were detected in hemolymph from mussels collected near a sea lion haul-out site (White Rock). These results suggest that mussels are being contaminated by protozoa carried in terrestrial runoff and/or shed in the feces of CSL. Furthermore, low numbers of oocysts and cysts morphologically similar toCryptosporidiumandGiardia, respectively, were detected in CSL fecal samples, suggesting that CSL could be a source and a host of protozoan parasites in coastal environments. The results of this study showed thatCryptosporidiumandGiardiaspp. from the feces of terrestrial animals and CSL can contaminate mussels and coastal environments.

New polymorphic microsatellite markers for California sea lions (Zalophus californianus)

2005 ◽  
Vol 5 (1) ◽  
pp. 140-142 ◽  
Author(s):  
F. D. HERNANDEZ-VELAZQUEZ ◽  
C. E. GALINDO-SANCHEZ ◽  
M. I. TAYLOR ◽  
J. DE LA ROSA-VELEZ ◽  
I. M. COTE ◽  
...  
Keyword(s):  
Microsatellite Markers ◽  
Zalophus Californianus ◽  
California Sea Lions ◽  
Sea Lions ◽  
Polymorphic Microsatellite
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