Multifocal Necrotizing Myopathy in Northern Elephant Seal (Mirounga angustirostris) Pups, San Miguel Island, California

2018 ◽  
Vol 56 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Terry R. Spraker ◽  
Tetiana A. Kuzmina ◽  
Eugene T. Lyons ◽  
Robert L. DeLong ◽  
Claire Simeone ◽  
...  
Keyword(s):  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Vacuolar Degeneration ◽  
Necrotizing Myopathy ◽  
Eosinophilic Cytoplasm ◽  
Northern Elephant Seals ◽  
San Miguel Island ◽  
System Degeneration ◽  
Causes Of Mortality

A field study addressing causes of mortality in freshly dead northern elephant seals ( Mirounga angustirostris, Gill, 1866) was conducted on San Miguel Island, California, in February 2015. Necropsies were performed on 18 pups ranging in age from stillbirths to approximately 7 to 8 weeks. The primary gross diagnoses in these pups included trauma, myopathy, starvation/emaciation, infections, congenital anomalies, and perinatal mortality. However, 6 (33%) had a previously unrecognized myopathy characterized by multiple white streaks that were most obvious within the inner layer of the abdominal wall and the small innermost ventral intercostal muscles. Following histological examination, 2 more pups from San Miguel Island and 6 pups from The Marine Mammal Center (Sausalito, California) were found to have similar lesions. Histologically, the lesions within the skeletal muscles were characterized by a multifocal polyphasic, mild to severe, acute to subacute necrotizing myopathy with mineralization. Acute necrosis and degeneration characterized by pyknotic nuclei, eosinophilic cytoplasm and cytoplasmic vacuolization were found in smooth muscle myocytes within the urinary bladder and digestive system. Degeneration of myocytes was present in the tunica media of a few small- to medium-sized vessels and was characterized by a vacuolar degeneration and occasionally necrosis. This condition has been termed multifocal necrotizing myopathy. A cause of this myopathy was not identified.

scholarly journals Causes of mortality in northern elephant seal pups on San Miguel Island, California

2020 ◽  
Vol 32 (2) ◽  
pp. 312-316
Author(s):  
Terry R. Spraker ◽  
Tetiana A. Kuzmina ◽  
Robert L. DeLong
Keyword(s):  
Congenital Anomalies ◽  
Bacterial Infections ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Hemolytic Streptococcus ◽  
E Coli ◽  
Necrotizing Myopathy ◽  
San Miguel Island ◽  
Causes Of Mortality

In February 2015, we conducted a field study of causes of mortality of northern elephant seal ( Mirounga angustirostris) pups on San Miguel Island, California. Autopsies were performed on 18 freshly dead pups. Ages of pups ranged from stillborn to 6–8 wk. Gross and histologic lesions included trauma (9 of 18 pups), multifocal necrotizing myopathy (8 of 18), starvation with emaciation (7 of 18), congenital anomalies (3 of 18), bacterial infections (3 of 18), and perinatal mortality (stillbirths and neonates; 2 of 18). Trauma and emaciation or starvation were the most significant contributors to death. Bacterial infections included hemolytic Escherichia coli isolated from the lungs of 2 pups with pneumonia. Additionally, non-hemolytic Streptococcus sp. and hemolytic E. coli were isolated from the liver of an emaciated pup that had mild multifocal suppurative hepatitis. Other lesions, including a previously described necrotizing myopathy, congenital anomalies, and bacterial infections, were detected concurrently in cases with starvation and/or emaciation or trauma.

Aggression in the Female Northern Elephant Seal, Mirounga Angustirostris

Behaviour ◽  
1978 ◽  
Vol 64 (1-2) ◽  
pp. 158-171 ◽  
Author(s):  
T.E. Christenson ◽  
B.J. Le Boeuf
Keyword(s):  
Reproductive Success ◽  
Aggressive Behavior ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Advantages And Disadvantages ◽  
Northern Elephant Seals ◽  
Pup Survival ◽  
Male Activity

AbstractMaternal aggressive behavior of northern elephant seals enhances reproductive success by increasing the likelihood of pup survival. Detailed observations of marked mother-pup pairs revealed that female aggressiveness increased dramatically after giving birth. Maternal aggressiveness also correlated negatively with the number of times the pup was bitten by alien females. Mothers of these pups were less aggressive than the 17 whose pups survived. Pup behavior was not directly related to mortality. Frequencies of interfemale aggressive encounters were compared for different beach areas. Aggression was most frequent on the smallest area, where interfemale distance was the shortest, and tidal action extreme. Aggression was least frequent on the sparcely populated beach, affected little by tide or male activity. Interfemale distance was greatest here. Reproductive advantages and disadvantages of pupping on each area are noted.

Diving behavior in relation to ambient water temperature in northern elephant seals

1994 ◽  
Vol 72 (4) ◽  
pp. 643-651 ◽  
Author(s):  
Hiroshi Hakoyama ◽  
Burney J. Le Boeuf ◽  
Yasuhiko Naito ◽  
Wataru Sakamoto
Keyword(s):  
Water Temperature ◽  
Elephant Seal ◽  
Diving Behavior ◽  
Mirounga Angustirostris ◽  
Ambient Water ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Northern Elephant Seals ◽  
Abrupt Changes ◽  
Ambient Water Temperature

Our aim was to describe changes in ambient water temperature during the course of migration by northern elephant seals (Mirounga angustirostris) and to examine evidence for the seal using abrupt temperature gradients for locating prey. During migration in the post breeding season, the diving patterns of 10 adult females and 7 breeding-age males from Año Nuevo, California, were recorded with time–depth recorders in 1989–1991. Recorded sea surface temperatures declined from 11–13 °C to a low of 3–9 °C as the seals moved north and increased as they returned. Depth of diving was not closely linked to sharp thermal gradients. A thermocline was evident only at the beginning and end of the migration in less than 100 m of water, where less than 2% of diving takes place. There were sex differences in the temperature range at the depths where 75% of diving and foraging occurred, owing in part to habitat separation. The temperatures were lower and the range narrower for females (4.2–5.2 °C at 388–622 m) than for males (5.3–6.0 °C at 179–439 m). We conclude that the northern elephant seal habitat does not provide abrupt changes in temperature that might serve as important cues for locating prey.

scholarly journals Parasitological examination of northern elephant seal (Mirounga angustirostris) pups for presence of hookworms (Uncinaria spp.) on San Miguel Island, California

2016 ◽  
Vol 53 (2) ◽  
pp. 191-194
Author(s):  
E. T. Lyons ◽  
T. A. Kuzmina ◽  
T. R. Spraker ◽  
R. L. Delong
Keyword(s):  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
California Sea Lions ◽  
Northern Elephant Seal ◽  
Parasitological Examination ◽  
Sea Lions ◽  
Fur Seals ◽  
Third Stage ◽  
Northern Fur Seals ◽  
San Miguel Island

SummaryNecropsy and extensive parasitological examination of dead northern elephant seal (NES) pups was done on San Miguel Island, California, in February, 2015. The main interest in the current study was to determine if hookworms were present in NESs on San Miguel Island where two hookworm species of the genus Uncinaria are known to be present - Uncinaria lyonsi in California sea lions and Uncinaria lucasi in northern fur seals. Hookworms were not detected in any of the NESs examined: stomachs or intestines of 16 pups, blubber of 13 pups and blubber of one bull. The results obtained in the present study of NESs on San Miguel Island plus similar finding on Año Nuevo State Reserve and The Marine Mammal Center provide strong indication that NES are not appropriate hosts for Uncinaria spp. Hookworm free-living third stage larvae, developed from eggs of California sea lions and northern fur seals, were recovered from sand. It seems that at this time, further search for hookworms in NESs would be nonproductive.

scholarly journals Treatment of Canine Tooth Fractures in the Northern Elephant Seal (Mirounga angustirostris): Three Cases

2019 ◽  
Vol 36 (1) ◽  
pp. 52-61
Author(s):  
Deborah L. Hodesson ◽  
Judy Force ◽  
Sophie Whoriskey ◽  
Cara Field
Keyword(s):  
Maternal Separation ◽  
Case Series ◽  
Elephant Seal ◽  
Anthropogenic Factors ◽  
Mirounga Angustirostris ◽  
Canine Tooth ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Northern Elephant Seals ◽  
Pulp Exposure

The Marine Mammal Center (TMMC) in Sausalito, California, rescues, rehabilitates, and releases hundreds of stranded northern elephant seals ( Mirounga angustirostris) each year. Common causes for stranding include maternal separation, malnutrition, and trauma. Causes of trauma include shark bites, conspecific interactions, and anthropogenic factors. Several cases of fractured teeth, secondary to presumed trauma, are presented to the center each year. This case series describes surgical approach and treatment of 3 young northern elephant seals that were admitted to TMMC for rehabilitation with tooth fractures with pulp exposure of maxillary or mandibular canine teeth. All 3 seals were successfully released into their natural environment.

scholarly journals Creation Nerves of the Lumbar and Sacral Plexus in California Sea Lions (Zalophus Californianus) and Northern Elephant Seals (Mirounga Angustirostris)/Formiranje Nerava Iz Lumbalnog I Sakralnog Pleksusa Kod Kalifornijskog Morskog Lava (Zalophus Californianus) I Severnomorskog Slona (Mirounga Angustirostris)

2014 ◽  
Vol 64 (3) ◽  
pp. 293-306 ◽  
Author(s):  
Mihelić Damir ◽  
Smodlaka Hrvoje ◽  
Tkalčić Suzana ◽  
Palmer Lauren ◽  
Mršić Gordan ◽  
...  
Keyword(s):  
Femoral Nerve ◽  
Elephant Seal ◽  
Zalophus Californianus ◽  
Mirounga Angustirostris ◽  
California Sea Lions ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Sea Lions ◽  
Northern Elephant Seals ◽  
Sacral Nerves

Abstract The lumbosacral plexus was investigated in the California sea lion and Northern elephant seal. In 9 California sea lions and 2 Northern elephant seals the femoral nerve rises from the ventral branches of the 3rd and 4th lumbar nerves, whilst in one male and two specimens of the Northern elephant seal the 5th lumbar nerve was also involved. Ventral branches of the 3rd and 4th lumbar nerves comprised the obturatorius nerve in 7 specimens; in 3 specimens the 5th lumbar nerve additionally supplements the obturatorius nerve. In Northern elephant seals the obturatorius nerve originates from the ventral branches of the 3rd, 4th and 5th lumbar nerves. The ischiadic nerve originates from the ventral branches of the 4th, 5th lumbar and 1st sacral nerves in 8 specimens California sea lions and in 2 North elephant seals. In 2 specimens of both species the 2nd sacral nerve also participates. The gluteal nerve created ventral branches of the 5th lumbar and 1st sacral nerves in three specimens; however in one specimen the 4th and 5th lumbar nerves gave rise to the same nerve in the Northern elephant seal. In California sea lions the gluteal nerve originates from the ventral branches of the 5th lumbar nerve in seven specimens, nonetheless in 3 specimens the 4th lumbar nerve also participates in its formation.

Mother-Offspring Separation and Acoustic Stereotypy: a Comparison of Call Morphology in Two Species of Pinnipeds

Behaviour ◽  
1992 ◽  
Vol 120 (1-2) ◽  
pp. 103-122 ◽  
Author(s):  
Stephen J. Insley
Keyword(s):  
Individual Variation ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Northern Fur Seal ◽  
Northern Elephant Seal ◽  
Fur Seals ◽  
Fur Seal ◽  
Species Analysis ◽  
Northern Elephant Seals ◽  
Discriminant Analyses

AbstractI have compared structural variation of the primary vocalizations used between mother-offspring pairs in two species of pinnipeds that differ fundamentally in their breeding behaviour: northern elephant seal (Mirounga angustirostris) mothers and offspring normally are together throughout the nursing period; northern fur seal (Callorhinus ursinus) females regularly separate from their offspring while nursing. Two predictions were tested: (1) these vocalizations should be individually-distinct (stereotyped) in females and pups of both species if they serve to function for recognition, and (2) because individuality should be more pronounced in a species where separations and reunions are common, the vocalizations used between northern fur seal mother-offspring pairs should be more individually-stereotyped than those of the northern elephant seal. Principal components analyses revealed structural differences between the calls of females and pups in both species. Analysis of variance showed the calls of individual seals to be acoustically distinct in all cases. The calls used between mother-offspring pairs of northern fur seals were more stereotyped than those of northern elephant seals. These calls had less within-individual variation, greater among-individual variation and were more often correctly predicted in discriminant analyses. The results indicate that selective pressure to develop vocal recognition exists in both species but is greater in the northern fur seal.

scholarly journals Where were the northern elephant seals? Holocene archaeology and biogeography of Mirounga angustirostris

The Holocene ◽  
2011 ◽  
Vol 21 (7) ◽  
pp. 1159-1166 ◽  
Author(s):  
Torben C. Rick ◽  
Robert L. DeLong ◽  
Jon M. Erlandson ◽  
Todd J. Braje ◽  
Terry L. Jones ◽  
...  
Keyword(s):  
Nineteenth Century ◽  
Elephant Seal ◽  
Archaeological Sites ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
The Holocene ◽  
Archaeological Data ◽  
Large Numbers ◽  
Northern Elephant Seals

Driven to the brink of extinction during the nineteenth century commercial fur and oil trade, northern elephant seal (NES, Mirounga angustirostris) populations now exceed 100 000 animals in the northeast Pacific from Alaska to Baja California. Because little is known about the biogeography and ecology of NES prior to the mid-nineteenth century, we synthesize and analyze the occurrence of NES remains in North American archaeological sites. Comparing these archaeological data with modern biogeographical, genetic, and behavioral data, we provide a trans-Holocene perspective on NES distribution and abundance. Compared with other pinnipeds, NES bones are relatively rare throughout the Holocene, even in California where they currently breed in large numbers. Low numbers of NES north of California match contemporary NES distribution, but extremely low occurrences in California suggest their abundance in this area was very different during the Holocene than today. We propose four hypotheses to explain this discrepancy, concluding that ancient human settlement and other activities may have displaced NES from many of their preferred modern habitats during much of the Holocene.

scholarly journals In-air hearing in Hawaiian monk seals: implications for understanding the auditory biology of Monachinae seals

2021 ◽  
Author(s):  
Brandi Ruscher ◽  
Jillian M. Sills ◽  
Beau P. Richter ◽  
Colleen Reichmuth
Keyword(s):  
Marine Mammals ◽  
Elephant Seal ◽  
Critical Ratio ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Hearing Ability ◽  
Highly Sensitive ◽  
Monk Seals ◽  
Management And Conservation ◽  
Hearing Abilities

AbstractThe auditory biology of Monachinae seals is poorly understood. Limited audiometric data and certain anatomical features suggest that these seals may have reduced sensitivity to airborne sounds compared to related species. Here, we describe the in-air hearing abilities of a Hawaiian monk seal (Neomonachus schauinslandi) trained to participate in a psychophysical paradigm. We report absolute (unmasked) thresholds for narrowband signals measured in quiet conditions across the range of hearing and masked thresholds measured in the presence of octave-band noise at two frequencies. The behavioral audiogram indicates a functional hearing range from 0.1 to 33 kHz and poor sensitivity, with detection thresholds above 40 dB re 20 µPa. Critical ratio measurements are elevated compared to those of other seals. The apparently reduced terrestrial hearing ability of this individual—considered with available auditory data for a northern elephant seal (Mirounga angustirostris)—suggests that hearing in Monachinae seals differs from that of the highly sensitive Phocinae seals. Exploration of phylogenetic relationships and anatomical traits support this claim. This work advances understanding of the evolution of hearing in amphibious marine mammals and provides updated information that can be used for management and conservation of endangered Hawaiian monk seals.

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