| nodular suppurative cutaneous cellulitis in a galapagos sea lion. | necropsy was performed on a sea lion (zalophus californianus wollebaeki), sacrificed in an advanced (pre-terminal) stage of disease, possibly represenatative of the galapagos epizootic of 1970-71. predominant features of the disease were nonumbilicated multiple suppurative cutaneous nodules, debilitation and loss of motor power. histopathological studies of the skin lesions disclosed suppurative cellulitis, with leucocytic invasion extending, in some instances, to all layers of the epidermis. ps ... | 1975 | 807749 |
| impacts of the jessica oil spill on sea lion (zalophus wollebaeki) populations. | following the jessica oil spill, a total of 79 oiled galápagos sea lions (zalophus wollebaeki) were recorded around the islands of san cristóbal, santa fé, isabela and floreana. almost half of these animals required washing and other treatment. one sea lion death and a high incidence of conjunctivitis and burns were detected during the period of the oil spill. sea lion populations exhibited a tendency for decline in the first months following the spill at all three colonies monitored close to th ... | 2003 | 12810095 |
| first report of parasites from pinnipeds in the galapagos islands, ecuador, with a description of a new species of philophthalmus (digenea: philophthalmidae). | a new species of digenetic trematode and 2 species of ectoparasites from zalophus wollebaeki silvertsen, 1953 (carnivora: otariidae) in the galapagos islands, ecuador, are reported. these include an eye fluke of philophthalmus looss, 1899 (echinostomata: philophthalmidae) as well as, to our knowledge, the first report of antarctophthirus microchir (trouessart and neumann, 1888) enderlein, 1906 (arthropoda: anoplura) and orthohalarachne diminuata (doetschman, 1944) newell, 1947 (arthropoda: acari ... | 2005 | 16108555 |
| beyond habitat requirements: individual fine-scale site fidelity in a colony of the galapagos sea lion (zalophus wollebaeki) creates conditions for social structuring. | site fidelity has been widely discussed, but rarely been related explicitly to a species' social context. this is surprising, as fine-scale site fidelity constitutes an important structural component in animal societies by setting limits to an individual's social interaction space. the study of fine-scale site fidelity is complicated by the fact that it is inextricably linked to patterns of habitat use. we here document fine-scale site fidelity in the galapagos sea lion (zalophus wollebaeki) str ... | 2007 | 17505851 |
| tracing early stages of species differentiation: ecological, morphological and genetic divergence of galápagos sea lion populations. | oceans are high gene flow environments that are traditionally believed to hamper the build-up of genetic divergence. despite this, divergence appears to occur occasionally at surprisingly small scales. the galápagos archipelago provides an ideal opportunity to examine the evolutionary processes of local divergence in an isolated marine environment. galápagos sea lions (zalophus wollebaeki) are top predators in this unique setting and have an essentially unlimited dispersal capacity across the en ... | 2008 | 18485220 |
| rotavirus infections in galapagos sea lions. | group a rotaviruses infect and cause diarrhea in the young of a broad range of terrestrial mammals, but it is unknown, to our knowledge, whether they infect marine mammals. during february and march of 2002 and 2003, we collected 125 serum samples and 18 rectal swab samples from galapagos sea lion pups (gsl, zalophus wollebaeki), and 22 serum samples from galapagos fur seal pups (gfs, arctocephalus galapagoensis) from nine islands of the galapagos archipelago, ecuador. sera were tested for antib ... | 2009 | 19617482 |
| male reproductive success and its behavioural correlates in a polygynous mammal, the galápagos sea lion (zalophus wollebaeki). | sexual selection theory predicts competitive males and choosy females. nevertheless, since molecular marker-based studies, paternity outside the expected mating patterns has increasingly been described. even in highly polygynous systems, where paternity is expected to be strongly skewed towards large, dominant males, alternative mating tactics have been suggested. we examined reproductive success in the polygynous galápagos sea lion (zalophus wollebaeki). semiaquatic territoriality allows female ... | 2010 | 20497325 |
| ddt in endangered galapagos sea lions (zalophus wollebaeki). | we characterize for the first time the presence of ddt and its metabolites in tropical galapagos sea lions (zalophus wolleabeki). ?ddt concentrations in galapagos sea lion pups sampled in 2005 and 2008 ranged from 16 to 3070 µg/kg lipid. concentrations of ?ddt in pups in 2008 averaged 525 µg/kg lipid and were 1.9 times higher than that (281 µg/kg lipid) detected in pups in 2005. these concentrations are lower than those reported in many pinnipeds elsewhere, comparable to those in hawaiian monk s ... | 2011 | 21353257 |
| immobilisation of free-ranging galapagos sea lions (zalophus californianus wollebaeki). | nine free-ranging galápagos sea lions were immobilised for marking, using a combination of ketamine (3 to 5 mg per kg) and xylazine (0.5 to 1.0 mg per kg). the degree of effect depended largely on the animals' behavioural and physiological state before immobilisation (after parturition, high arousal, subject to aggression, etc.) all nine animals survived. overheating in the immobilised state may quickly result in heart and circulatory failures. | 2004 | 516341 |
| pup mortality and evidence for pathogen exposure in galapagos sea lions (zalophus wollebaeki) on san cristobal island, galapagos, ecuador. | the galapagos sea lion ( zalophus wollebaeki ), an endangered species, experiences high pup mortality (up to 100%) in years when el niño events reduce food supply in the galapagos islands. mortality of pups in non-el niño years is estimated to be 5% in undisturbed colonies. from 2009 to 2012 we observed high pup mortality (up to 66%) in colonies close to the galapagos capital, puerto baquerizo moreno, where contact with humans, domestic animals, and rats is frequent. gross postmortem findings fr ... | 2017 | 28318380 |
| individual foraging strategies reveal niche overlap between endangered galapagos pinnipeds. | most competition studies between species are conducted from a population-level approach. few studies have examined inter-specific competition in conjunction with intra-specific competition, with an individual-based approach. to our knowledge, none has been conducted on marine top predators. sympatric galapagos fur seals (arctocephalus galapagoensis) and sea lions (zalophus wollebaeki) share similar geographic habitats and potentially compete. we studied their foraging niche overlap at cabo dougl ... | 2013 | 23967096 |
| same size--same niche? foraging niche separation between sympatric juvenile galapagos sea lions and adult galapagos fur seals. | 1. in vertebrates, patterns of resource utilization change throughout development according to age- and or size-specific abilities and requirements. thus, interspecific competition affects different age classes differently. 2. adults of sympatric species often show distinct foraging niche segregation, but juvenile resource use might overlap with adult competitors of similar body size. resultant negative effects on juveniles can have important consequences for population dynamics, yet such intera ... | 2013 | 23351022 |
| drastic effects of el niño on galapagos pinnipeds. | population dynamics of pinnipeds living in the tropical upwelling ecosystem of the galapagos were strongly influenced by the 1982-83 southern oscillation-el niño (en) event which was the strongest recorded in this century. the galapagos fur seal (arctocephalus galapagoensis) population lost the four youngest year classes (1980-1983) almost entirely and approximately 30% of the adult females and non-territorial males. mortality of large territorial males was almost 100%. most of the 1982 year cla ... | 1985 | 28309839 |
| accuracy of argos locations of pinnipeds at-sea estimated using fastloc gps. | argos satellite telemetry is one of the most widely used methods to track the movements of free-ranging marine and terrestrial animals and is fundamental to studies of foraging ecology, migratory behavior and habitat-use. argos location estimates do not include complete error estimations, and for many marine organisms, the most commonly acquired locations (location class 0, a, b, or z) are provided with no declared error estimate. | 2010 | 20090942 |
| population abundance of the endangered galapagos sea lion zalophus wollebaeki in the southeastern galapagos archipelago. | there is great concern regarding the population status of the endangered galapagos sea lion (gsl) because it has drastically decreased over the last 30 years. we determined the population size and growth trend of the gsl in the galapagos southeastern region (ser) at three population levels based on the available census data: 1) ser (2011-2015), including 13 rookeries on the four islands san cristóbal (sc), española, floreana, and santa fe, comprising 58% of the archipelago's population; 2) sc (2 ... | 2017 | 28052081 |
| on the challenge of interpreting census data: insights from a study of an endangered pinniped. | population monitoring is vital for conservation and management. however, simple counts of animals can be misleading and this problem is exacerbated in seals (pinnipeds) where individuals spend much time foraging away from colonies. we analyzed a 13-year-series of census data of galapagos sea lions (zalophus wollebaeki) from the colony of caamaño, an islet in the center of the galapagos archipelago where a large proportion of animals was individually marked. based on regular resighting efforts du ... | 2016 | 27148735 |
| stable isotopes reveal long-term fidelity to foraging grounds in the galapagos sea lion (zalophus wollebaeki). | most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. however, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. here, stable isotope ratios in the skull bone of adult galapagos sea lions (zalophus wollebaeki) were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the galapagos archipe ... | 2016 | 26808381 |
| context-dependent associations between heterozygosity and immune variation in a wild carnivore. | a multitude of correlations between heterozygosity and fitness proxies associated with disease have been reported from wild populations, but the genetic basis of these associations is unresolved. we used a longitudinal dataset on wild galapagos sea lions (zalophus wollebaeki) to develop a relatively new perspective on this problem, by testing for associations between heterozygosity and immune variation across age classes and between ecological contexts. | 2015 | 26537228 |
| health status of galápagos sea lions (zalophus wollebaeki) on san cristóbal island rookeries determined by hematology, biochemistry, blood gases, and physical examination. | the galápagos sea lion, zalophus wollebaeki, is an endemic and endangered species subject to population decline associated with environmental variability, such as el niño events, constant feeding stress, and exposure to diseases through contact with introduced species. reference blood parameter intervals have been published for some pinniped species, but baseline biochemical and blood gas values are lacking from z. wollebaeki. we analyzed blood samples from 30 juvenile galápagos sea lions (19 fe ... | 2016 | 26528574 |
| differences in foraging ecology align with genetically divergent ecotypes of a highly mobile marine top predator. | foraging differentiation within a species can contribute to restricted gene flow between ecologically different groups, promoting ecological speciation. galapagos sea lions (zalophus wollebaeki) show genetic and morphological divergence between the western and central archipelago, possibly as a result of an ecologically mediated contrast in the marine habitat. we use global positioning system (gps) data, time-depth recordings (tdr), stable isotope and scat data to compare foraging habitat charac ... | 2015 | 26307593 |
| competition influence in the segregation of the trophic niche of otariids: a case study using isotopic bayesian mixing models in galapagos pinnipeds. | the feeding success of predators is associated with the competition level for resources, and, thus, sympatric species are exposed to a potential trophic overlap. isotopic bayesian mixing models should provide a better understanding of the contribution of preys to the diet of predators and the feeding behavior of a species over time. | 2014 | 25366402 |
| applicability of single-camera photogrammetry to determine body dimensions of pinnipeds: galapagos sea lions as an example. | morphological features correlate with many life history traits and are therefore of high interest to behavioral and evolutionary biologists. photogrammetry provides a useful tool to collect morphological data from species for which measurements are otherwise difficult to obtain. this method reduces disturbance and avoids capture stress. using the galapagos sea lion (zalophus wollebaeki) as a model system, we tested the applicability of single-camera photogrammetry in combination with laser dista ... | 2014 | 24987983 |
| immune activity, body condition and human-associated environmental impacts in a wild marine mammal. | within individuals, immunity may compete with other life history traits for resources, such as energy and protein, and the damage caused by immunopathology can sometimes outweigh the protective benefits that immune responses confer. however, our understanding of the costs of immunity in the wild and how they relate to the myriad energetic demands on free-ranging organisms is limited. the endangered galapagos sea lion (zalophus wollebaeki) is threatened simultaneously by disease from domestic ani ... | 2013 | 23840603 |
| divergent allele advantage at mhc-drb through direct and maternal genotypic effects and its consequences for allele pool composition and mating. | it is still debated whether main individual fitness differences in natural populations can be attributed to genome-wide effects or to particular loci of outstanding functional importance such as the major histocompatibility complex (mhc). in a long-term monitoring project on galápagos sea lions (zalophus wollebaeki), we collected comprehensive fitness and mating data for a total of 506 individuals. controlling for genome-wide inbreeding, we find strong associations between the mhc locus and near ... | 2013 | 23677346 |
| mama's boy: sex differences in juvenile survival in a highly dimorphic large mammal, the galapagos sea lion. | in many mammals, early survival differs between the sexes, with males proving the more fragile sex ["fragile male (fm) hypothesis"], especially in sexually dimorphic species where males are the larger sex. male-biased allocation (mba) by females may offset this difference. here, we evaluate support for the fm and mba hypotheses using a dataset on galapagos sea lions (zalophus wollebaeki). we statistically model sex-specific survival as it depends on body mass and environmental conditions (sea su ... | 2013 | 23053230 |
| 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 |
| ddt strikes back: galapagos sea lions face increasing health risks. | | 2011 | 21809785 |
| polychlorinated biphenyls and polybrominated diphenyl ethers in galapagos sea lions (zalophus wollebaeki). | concentrations of polychlorinated biphenyls (pcbs), polybrominated diphenyl ethers (pbdes), polychlorinated dibenzo-p-dioxins (pcdds), and polychlorinated dibenzofurans (pcdfs) were measured in muscle-blubber biopsy samples from 21 galapagos sea lion (zalophus wollebaeki) pups that were live captured in the galapagos islands (ecuador) using gas chromatography/high-resolution mass spectrometry. only traces of pbdes were detected in one male pup, whereas pcdds and pcdfs were not detected in any sa ... | 2009 | 19499971 |
| kin in space: social viscosity in a spatially and genetically substructured network. | population substructuring is a fundamental aspect of animal societies. a growing number of theoretical studies recognize that who-meets-whom is not random, but rather determined by spatial relationships or illustrated by social networks. structural properties of large highly dynamic social systems are notoriously difficult to unravel. network approaches provide powerful ways to analyse the intricate relationships between social behaviour, dispersal strategies and genetic structure. applying netw ... | 2008 | 18522913 |
| galápagos and californian sea lions are separate species: genetic analysis of the genus zalophus and its implications for conservation management. | accurate formal taxonomic designations are thought to be of critical importance for the conservation of endangered taxa. the galápagos sea lion (gsl), being appreciated as a key element of the galápagos marine ecosystem, has lately been listed as 'vulnerable' by the iucn. to date there is, however, hardly any scientific evidence, whether it constitutes a separate entity from its abundant californian neighbour (csl). in this paper, we delineate the taxonomic relationships within the genus zalophu ... | 2007 | 17868473 |
| ketamine xylazine combination for the immobilisation of galapagos sea lions and fur seals. | | 1983 | 6845605 |
| a paternal role in galapagos sea lions? | | 1974 | 28564845 |
| galapagos sea lions are paternal. | | 1974 | 28564839 |
| evaluation of the ophthalmic disease and histopathologic effects due to the ocular trematode philophthalmus zalophi on juvenile galapagos sea lions ( zalophus wollebaeki). | the galapagos sea lion ( zalophus wollebaeki) is an otariid species endemic to the galapagos archipelago and is currently listed as endangered. the ocular trematode philophthalmus zalophi was recently reported to affect the survival of juvenile galapagos sea lions on santa cruz island, resulting in marked ophthalmic changes. this study evaluated the ophthalmic disease and histopathologic effects of p. zalophi on juvenile galapagos sea lions in the largest rookery located on san cristóbal island. ... | 2018 | 30212353 |
| intestinal parasites in galapagos sea lions (zalophus wollebaeki) sivertsen, 1953 on san cristóbal island, galápagos, ecuador. | knowledge regarding endoparasites of galapagos sea lions, zalophus wollebaeki sivertsen, 1953, is limited to 1 report. herein, we examined feces extracted from the lower gastro-intestinal tract of 15 galapagos sea lions (gsl) plus 14 fecal mounds nearby gsl at 4 locations on san cristobal island, galapagos beginning in may continuing through june 2016. using standard fecal flotation and sedimentation techniques, lungworm larvae, suggestive of parafilaroides and otostrongylus sp., eggs of pseudop ... | 2018 | 30141720 |
| intraspecific variation in feeding strategies of galapagos sea lions: a case of trophic specialization. | the trophic behavior of marine predators varies according to the level of competition to which they are exposed. in general, populations that inhabit lower productivity systems face a strong intraspecific competition, which contributes to the development of different foraging strategies to maximize nutritional efficiency. given the high trophic flexibility of zalophus wollebaeki, this species is considered appropriate for the analysis of such behavior. furthermore, this trophic flexibility has a ... | 2017 | 29059188 |