Functional classification of harbor seal (Phoca vitulina) dives using depth profiles, swimming velocity, and an index of foraging success

1999 ◽  
Vol 77 (1) ◽  
pp. 74-87 ◽  
Author(s):  
Véronique Lesage ◽  
Mike O Hammill ◽  
Kit M Kovacs
Keyword(s):  
Minimum Cost ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Swimming Velocity ◽  
Harbor Seals ◽  
Cost Of Transport ◽  
Lawrence Estuary ◽  
Stomach Temperature ◽  
St Lawrence Estuary

Time-depth-speed recorders and stomach-temperature sensors were deployed on 11 harbor seals (Phoca vitulina) in the St. Lawrence estuary to examine their diving and foraging behavior. Fifty-four percent of dives were to depths of <4 m. Dives that were [Formula: see text] 4 m deep were classified into five distinct types, using a combination of principal components analysis and hierarchical and nonhierarchical clustering analyses. Feeding, indicated by a sharp decline in stomach temperature, occurred during dives of all five types, four of which were U-shaped, while one was V-shaped. Seals swam at speeds near the minimum cost of transport (MCT) during descents and ascents. V-shaped dives had mean depths of 5.8 m, lasted an average of 40 s, and often preceded or followed periods of shallow-water (<4 m) activity. Seals invariably dove to the bottom when performing U-shaped dives. These dives were to an average depth of 20 m during daylight and occurred in shallower waters (~8 m) at twilight and during the night. Once on the bottom, seals (i) swam at MCT speeds with occasional bursts of speed, (ii) swam at speeds near MCT but not exceeding it, or (iii) remained stationary or swam slowly at about 0.15 m/s, occasionally swimming faster. It is unlikely that all dives to depths [Formula: see text] 4 m are dedicated to foraging. However, the temporal segregation of dive types suggests that all types are used during foraging, although they may represent different strategies.

Hormonal changes and enforced diving in the harbor seal Phoca vitulina. II. Plasma catecholamines

1982 ◽  
Vol 242 (5) ◽  
pp. R528-R532 ◽  
Author(s):  
A. J. Hance ◽  
E. D. Robin ◽  
J. B. Halter ◽  
N. Lewiston ◽  
D. A. Robin ◽  
...  
Keyword(s):  
Recovery Period ◽  
Control Period ◽  
Plasma Catecholamines ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Hormonal Changes ◽  
Inotropic Effects ◽  
Arterial Constriction

Plasma epinephrine and norepinephrine concentrations were measured in five harbor seals, Phoca vitulina, during a control period, during a 6-min dive, and during a 30-min postdiving recovery period. Measurements were performed with and without prior glucose administration. Control epinephrine concentrations [189 +/- 118 (SD) pg/ml] and norepinephrine concentrations (340 +/- 191 pg/ml) were similar to resting values in humans. During diving there are dramatic increases in both epinephrine and norepinephrine concentrations, which returned to control values by 30 min of the postdiving recovery period. A similar pattern was found after glucose infusion. The increased catecholamines were not the primary mechanism responsible for arterial constriction during the dive. Persistent diving bradycardia suggests obliteration of the chronotropic effects of catecholamines during the dive. An unchanged stroke volume suggests obliteration of the inotropic effects of catecholamines during the dive. Catecholamines do not appear to be involved in postdiving hyperglycemia and hyperglucogenemia. Neither the regulatory role of increased catecholamines nor the physiological function of increased catecholamines was apparent from the studies. However, dramatic increases in plasma catecholamines during diving appear to be an important component of the hormonal response to prolonged diving in aquatic mammals.

scholarly journals Morphological characteristics of harbor seal (Phoca vitulina) whiskers and their use in dietary reconstruction using stable isotope ratios

2018 ◽  
Vol 96 (11) ◽  
pp. 1255-1263 ◽  
Author(s):  
Justin Smith ◽  
Shawna Karpovich ◽  
Greg A. Breed ◽  
Diane M. O’Brien
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Whisker Growth ◽  
Morphological Characteristics ◽  
Isotope Ratios ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Dietary Reconstruction ◽  
Whisker Morphology

We investigated whether inferences about harbor seal (Phoca vitulina Linnaeus, 1758) whisker shed status and growth rates based on whisker morphology could improve dietary time series from whisker isotopic profiles. We identified morphometric characteristics of Alaskan harbor seal whiskers, including a smooth root section (SRS) and a bumpy section. The SRS was longer for spring versus fall-collected whiskers and matched the length of fully grown, shed whiskers. Thus, SRS length can differentiate whisker shed and growth status, and we used it to determine the sequence of whisker shedding by cohort in summer-captured harbor seals. The mean interbump length (IBL) correlated with whisker length, potentially providing a proxy for whisker growth rate. We compared carbon isotope ratios (expressed as δ13C values) along the three longest whiskers from 10 harbor seals, using two approaches for converting whisker position to date: (1) a standard growth rate constant based on captive studies and (2) individually adjusted growth rates based on whisker morphology. Intraindividual patterns of whisker δ13C values became more synchronous when expressed by deposition date rather than by position; however, adjusting growth rates based on IBL did not improve synchrony further. These findings suggest that whisker morphology can contribute whisker growth rate and shedding information for dietary reconstruction.

Influence of storms and maternal size on mother–pup separations and fostering in the harbor seal, Phoca vitulina

1992 ◽  
Vol 70 (8) ◽  
pp. 1640-1644 ◽  
Author(s):  
Daryl J. Boness ◽  
Don Bowen ◽  
Sara J. Iverson ◽  
Olav T. Oftedal
Keyword(s):  
Surface Current ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Frequency Of Occurrence ◽  
Lactation Period ◽  
Maternal Size ◽  
Proximate Causes ◽  
Previous Location

Fostering behavior has been documented in a large number of mammals and birds, but its frequency of occurrence and proximate causes are poorly understood in most species. Ten percent of a sample of 76 paint-marked female harbor seals (Phoca vitulina) fostered pups for some portion of the lactation period. Fostering appears to be associated with females having lost their own pup. In a subsample of 30 pairs that were followed closely, 3 of 16 females that lost their pups fostered, but none of 14 females that maintained continuous association with their pups throughout lactation did so. Smaller, and presumably younger, females were significantly more likely to become separated from their pups than were larger, and presumably older, females (73 vs. 33%). A high proportion (68%) of 35 separations observed occurred during the same day as, or within 1 day following, a storm. In 7 of 8 instances where we relocated pups after they were separated from their mothers during a storm, we found them in the direction of the surface current, 4.9 km from their previous location, on average. These data suggest that storms were the primary cause of separation of harbor seal mothers from their pups, and that younger mothers may be more likely to become separated from their pups. As fostering only occurs after a mother has lost her pup, we suggest that fostering, too, may be more likely among younger females.

Adaptations to diving in the harbor seal— gas exchange and ventilatory response to CO2

1963 ◽  
Vol 205 (6) ◽  
pp. 1175-1177 ◽  
Author(s):  
Eugene D. Robin ◽  
H. Victor Murdaugh ◽  
William Pyron ◽  
Edgar Weiss ◽  
Peter Soteres
Keyword(s):  
Gas Exchange ◽  
Ventilatory Response ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Pulmonary Gas Exchange ◽  
Respiratory Center ◽  
Harbor Seals ◽  
Response Curves ◽  
Ventilatory Response To Co2

Pulmonary gas exchange and the ventilatory response to CO2 were measured in six female harbor seals, Phoca vitulina. Mean Paco2 (48 ± 6 mm Hg) is higher in the seal and mean Pao2 (88 ± 9 mm Hg) is lower than the corresponding value in man. The seal shows a depressed ventilatory response to CO2 both in terms of slope and intercept of CO2 response curves. The depressed respiratory center sensitivity to CO2 presumably is an adaptative mechanism permitting prolonged diving in this species.

Swimming velocities, breathing patterns, and estimated costs of locomotion in migrating gray whales, Eschrichtius robustus

1983 ◽  
Vol 61 (3) ◽  
pp. 647-652 ◽  
Author(s):  
James L. Sumich
Keyword(s):  
Minimum Cost ◽  
San Diego County ◽  
Swimming Velocity ◽  
Eschrichtius Robustus ◽  
Breathing Patterns ◽  
Method Of Least Squares ◽  
Cost Of Transport ◽  
Total Drag ◽  
Gray Whales ◽  
Energy Expenditures

This study was conducted to determine the swimming velocities and breathing patterns of south-migrating gray whales (Eschrichtius robustus) and to estimate their minimum costs of transport during migration. Swimming velocities and breathing patterns were monitored with theodolite techniques from a coastal vantage point on Point Loma, San Diego County, CA. Estimates of energy expenditures were based on observed breathing rates and on extrapolations of tidal lung volume and oxygen uptake measurements made on unrestrained and on captive gray whales. The results of 74 whales monitored over 354 whale∙km yielded mean velocities of 2.0 m∙s−1 and mean breathing rates of 0.72 breaths∙min−1. The regression of breathing rates on swimming velocities (V) by the method of least squares is best described by the equation, breathing rate = 0.5 + 0.024 V3.0. The calculated minimum cost of transport for a 12-m, 15-t whale was 0.046 W∙s∙N−1∙m−1 at the observed mean swimming velocity of 2 m∙s−1 during the southward migration. The coefficient of total drag was estimated to be 0.06. Rates of lipid depletion approximate 6% of body weight per month if no supplementary food intake occurs for the 4- to 6-month period each year that gray whales are presumed to fast.

Stomach Temperature Telemetry Reveals that Harbor Seal (Phoca vitulina) Pups Primarily Nurse in the Water

2010 ◽  
Vol 36 (3) ◽  
pp. 270-277 ◽  
Author(s):  
Jason F. Schreer ◽  
Jennifer L. Lapierre ◽  
Michael O. Hammill
Keyword(s):  
Harbor Seal ◽  
Phoca Vitulina ◽  
Stomach Temperature ◽  
Temperature Telemetry

scholarly journals Distance Estimation in Reproduction Tasks in a Harbor Seal (Phoca vitulina)

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 938
Author(s):  
Eric Maaß ◽  
Frederike D. Hanke
Keyword(s):  
Visual Information ◽  
Path Integration ◽  
Visual Cues ◽  
Distance Estimation ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Experimental Paradigm ◽  
Feeding Grounds ◽  
Specific Distance

Harbor seals commute between haul-out places and feeding grounds close to the shore or in the open ocean, which is considered a low structured environment, at first sight not providing many cues for orientation/navigation. Nevertheless, seals are well-oriented. For returning to a specific location, seals may use both external and internal cues to, for example, perform path integration requiring the integration of distances traveled and angles steered. We herein assessed the seal’s ability to estimate distances, previously swum or unknown, in reproduction tasks. Reproduction tasks refer to an experimental paradigm in which the experimental animal is required to swim a specific distance first and subsequently reproduce this distance, with visual cues present or absent. The seal was able to estimate and then reproduce distances (0.5–18.5 m) with the smallest error below 10% of the actual distance, and its precision was higher with distances repeatedly swum compared to its performance with unfamiliar distances. In the absence of visual cues, the seal’s performance slightly dropped; however, it was still able to perform the task with an error of 21%. In conclusion, distance estimation may help seals to navigate precisely towards their goals, even if, for example, visual information is not available.

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